Multilayer sintered ceramic body

Abstract

The invention relates to a multilayer sintered ceramic body. Disclosed herein is a multilayer sintered ceramic body comprising: at least one first layer comprising polycrystalline YAG, where the at least one first layer comprising polycrystalline YAG comprises pores, where the pores have a maximum size of 0.1 [mu] m to 5 [mu] m; at least one second layer comprising alumina and zirconia, wherein the zirconia comprises at least one of stabilized zirconia and partially stabilized zirconia; and at least one third layer comprising at least one of YAG, aluminum oxide, and zirconium oxide wherein the absolute value of the difference in coefficient of thermal expansion (CTE) between the at least one first layer, the at least one second layer, and the at least one third layer is 0 to 0.75 x 10-6 / DEG C, as measured according to ASTM E228-17, and the absolute value of the difference in coefficient of thermal expansion (CTE) between the at least one first layer, the at least one second layer, and the at least one third layer is 0 to 0.75 x 10-6 / DEG C, wherein the at least one first layer, the at least one second layer and the at least one third layer form a monolithic multilayer sintered ceramic body. The invention also discloses a preparation method.

Description

[0001] This application is a divisional application of the invention patent application with the application date of December 17, 2021, application number 202180083025.0, and invention name “Multi-layer sintered ceramic body”. Technical Field

[0002] The present disclosure relates to corrosion-resistant multilayer sintered ceramics and components formed therefrom, methods of producing the ceramics, and use within semiconductor plasma processing chambers. Background Art

[0003] Semiconductor processing requires the use of halogen-based gases in combination with high electric and magnetic fields to create a plasma environment. This plasma environment is generated within a vacuum chamber for etching or depositing materials on semiconductor substrates. These vacuum chambers include component parts such as disks or windows, liners, injectors, rings, and cylinders. During semiconductor plasma processing, the substrate is typically supported within the vacuum chamber by a substrate holder, as disclosed, for example, in US 5,262,029 and US 5,838,529. The process gas used to create the plasma processing environment can be supplied to the chamber by various gas supply systems. Some processes involve the use of radio frequency (RF) fields, and the process gas is introduced into the processing chamber while the RF field is applied to the process gas to generate a plasma of the process gas. The ceramic materials used to form these components, especially those used for RF applications, need to have a relative humidity of approximately 1×10 -3 and a lower dielectric loss tangent. Dielectric losses higher than this cause overheating and hot spots within the component during use, leading to process variability and yield loss. The use of components made from high purity starting powders and manufacturing processes that maintain initial purity will provide sintered ceramics that meet these low loss requirements. The harsh plasma processing environment requires the use of highly corrosion and erosion resistant materials for chamber components. These components have been formed from materials that provide corrosion and erosion resistance in plasma environments and have been described, for example, in US 5,798,016, US 5,911,852, US 6,123,791 and US 6,352,611. In addition, plasma processing chambers have been designed to include components such as disks, rings and cylinders that confine the plasma to the wafer being processed. However, these parts used in plasma processing chambers are constantly attacked by the plasma and therefore eventually corrode, erode or accumulate contaminants and polymer buildup. Plasma etching and deposition conditions lead to corrosion and roughening of the surfaces of chamber parts that are exposed to the plasma. This corrosion is caused by

[0004] The release of particles from component surfaces into the chamber contributes to wafer-level contamination, leading to yield loss in semiconductor devices.

[0005] To address this issue, chamber components typically have a surface layer that is resistant to corrosion and erosion when exposed to process gases. The surface layer can be formed on a substrate or base that may have excellent mechanical properties, electrical properties, or other preferred properties. It is known that corrosion-resistant films or coatings such as yttrium oxide or yttrium aluminum garnet (YAG) can be deposited on a substrate or base formed from a different material. Corrosion-resistant films or coatings are cheaper and stronger than most corrosion-resistant materials. Such films or coatings have been made by several methods. Vapor deposition has been used to deposit corrosion-resistant films on substrates, but due to internal film stresses, vapor deposition is limited to relatively thin layers and often has small pores in the film. These internal film stresses produce poor interlayer adhesion and lead to delamination, usually at the interface between the corrosion-resistant film and the substrate, making these layers susceptible to cracking and flaking, thereby leading to undesirable particulate contamination. Corrosion-resistant coatings or films made by aerosol or plasma spraying techniques typically exhibit a high level of porosity of 3% to about 50%, and a corresponding low density. Furthermore, these thin films produced by aerosol or spray coating methods exhibit poor interfacial adhesion between the substrate material and the corrosion-resistant layer, leading to chipping and flaking and subsequent chamber contamination. Figure 1 Schematic illustration of delamination and cracking of a thin film deposited on a ceramic substrate.

[0006] Commercially available methods for depositing thin films on sintered substrates limit film thickness to less than about 0.45 mm and less. Such film thicknesses often have pores resulting from inhomogeneities in the underlying substrate, and the presence of pores and limited film thickness make the film surface layer susceptible to cracking, exposing the underlying substrate to corrosive process gases and particle generation during processing.

[0007] Other methods of forming corrosion-resistant, high-strength sintered bodies and / or components include laminating preformed films, applying pressure to the films to form a laminate, and then co-sintering the laminate. These methods typically use pressureless sintering, and the flatness of the sintered body depends on closely matching the sintering rates of the individual films. Figure 2As schematically depicted in , if the sintering rate of the top film (Film A) is greater than the sintering rate of the bottom film (Film B), the sintered ceramic laminate will have a concave curvature, while if the sintering rate of the bottom film (Film B) is greater than the sintering rate of the top film (Film A), the sintered ceramic laminate will have a convex curvature (both are configured with the top film Film A facing up). The change in sintering rate produces residual stresses in the sintered laminate, making it prone to breakage, microcracking and subsequent particle release, especially in large sizes. Therefore, the materials selected for co-sintering are limited to those with the same or very similar sintering time, temperature and duration profiles as known to those skilled in the art. In addition, these sintered laminates typically exhibit poor interfacial adhesion between layers, resulting in peeling and flaking of the top layer, as well as low density, making them prone to breakage, delamination and cracking.

[0008] The machining of holes and features to form parts from ceramic bodies can create small, visually undetectable microcracks below (subsurface) and above the surface of these brittle, non-metallic materials. This surface and subsurface damage can lead to particle contamination due to corrosion or spalling and / or fracture of the brittle material. The machinability of parts formed from brittle materials becomes increasingly challenging to prevent particle release into the plasma processing chamber and / or to prevent fracture and cracking (especially at large part sizes).

[0009] Therefore, there is a need in the art for a multilayer sintered ceramic body for use in plasma processing chambers that has a combination of plasma resistance, high interlayer adhesion, high mechanical strength, and improved machinability. In particular, there is a need for a corrosion-resistant, high-strength sintered ceramic body of large size (greater than 100 mm, e.g., from 100 mm to 625 mm) to enable large-scale manufacturing of semiconductor devices. Summary of the Invention

[0010] To meet these and other needs, and in view of its purposes, the present disclosure provides embodiments of multilayer sintered ceramic bodies and methods for making large multilayer sintered ceramic bodies having improved mechanical, electrical, and thermal properties and capable of being handled.

[0011] Sintered ceramic bodies (also referred to herein as multilayer sintered ceramic bodies or corrosion-resistant bodies) and methods of making them are described herein. These ceramic bodies offer high corrosion resistance to chlorine- and fluorine-based process gases, low dielectric loss, high thermal conductivity, and enhanced machinability, and are therefore desirable for use as components in semiconductor processing chambers utilizing halogen-based process gases. The ceramic bodies are particularly suitable for use as components in large chambers having dimensions of 100 mm and larger.

[0012] Embodiment 1. A multilayer sintered ceramic body comprising: at least one first layer comprising polycrystalline YAG, wherein the at least one first layer comprising polycrystalline YAG comprises pores, wherein the pores have a maximum dimension of 0.1 μm to 5 μm; at least one second layer comprising aluminum oxide and zirconium oxide, wherein the zirconium oxide comprises at least one of stabilized zirconium oxide and partially stabilized zirconium oxide; and at least one third layer comprising at least one selected from the group consisting of YAG, aluminum oxide, and zirconium oxide, wherein the at least one second layer is disposed between the at least one first layer and the at least one third layer, wherein the absolute value of the difference in coefficient of thermal expansion (CTE) between any of the at least one first layer, the at least one second layer, and the at least one third layer, as measured in accordance with ASTM E228-17, is 0 to 0.75×10 -6 / °C, and wherein the at least one first layer, the at least one second layer and the at least one third layer form an integrally sintered ceramic body.

[0013] Embodiment 2. The multilayer sintered ceramic body according to Embodiment 1, wherein the absolute value of the difference in thermal expansion coefficient between any of the layers is 0 to 0.7×10 −6 / ° C.

[0014] Embodiment 3. A multilayer sintered ceramic body according to any of the preceding embodiments, wherein the absolute value of the difference in coefficient of thermal expansion (CTE) between any of the at least one first layer, the at least one second layer, and the at least one third layer is maintained over the entire temperature range of 200°C to 1400°C.

[0015] Embodiment 4. The multi-layer sintered ceramic body according to any of the preceding embodiments, wherein the at least one first layer has a density of 4.47 g / cc to 4.56 g / cc as measured according to ASTM B962-17.

[0016] Embodiment 5. The multilayer sintered ceramic body according to any of the preceding embodiments, wherein the at least one first layer has an Sa of 0.0005 μm to 2 μm as measured according to ISO Standard 25178-2-2012 or an Sz of 0.3 μm to 5 μm as measured according to ISO Standard 25178-2-2012.

[0017] Embodiment 6. The multilayer sintered ceramic body according to any one of the preceding embodiments, wherein the at least one second layer comprises zirconium oxide in an amount of 10% to 30% by volume relative to the volume of the at least one second layer.

[0018] Embodiment 7. The multi-layer sintered ceramic body of any of the preceding embodiments, wherein the at least one second layer comprises partially stabilized zirconia.

[0019] Embodiment 8. The multi-layer sintered ceramic body according to any of the preceding embodiments, having a maximum dimension of 100 mm to about 625 mm.

[0020] Embodiment 9. A multi-layer sintered ceramic body according to any of the preceding embodiments, wherein the at least one second layer comprises about 16 volume % zirconium oxide relative to the volume of the at least one second layer.

[0021] Embodiment 10. A multilayer sintered ceramic body according to any one of the preceding embodiments, wherein the at least one first layer comprises 98% to 99.9% polycrystalline YAG by volume, as measured using XRD, SEM and image processing methods, and the balance comprises at least one crystalline phase selected from the group consisting of aluminum oxide, yttrium oxide, YAM and YAP, and combinations thereof.

[0022] Embodiment 11. The multilayer sintered ceramic body of any preceding embodiment, wherein the at least one first layer comprising polycrystalline YAG comprises pores, wherein the pores have a maximum dimension of 0.1 μm to 1 μm as measured using a SEM.

[0023] Embodiment 12. The multilayer sintered ceramic body of any one of the preceding embodiments, wherein the at least one first layer comprising polycrystalline YAG has a thickness of about 2 μm as measured using SEM. 2 / mm 2 to about 800 μm 2 / mm 2 Cumulative pore distribution.

[0024] Embodiment 13. The multilayer sintered ceramic body of any preceding embodiment, wherein the at least one first layer comprising polycrystalline YAG has a porosity of 0.0005% to 2% by surface area as measured using a SEM.

[0025] Embodiment 14. A multilayer sintered ceramic body according to any one of the preceding embodiments, wherein the at least one first layer comprising polycrystalline YAG has a total impurity content of less than 5 ppm to 50 ppm relative to the mass of the at least one first layer as measured using an ICPMS method.

[0026] Embodiment 15. The multi-layer sintered ceramic body of any preceding embodiment, wherein the at least one second layer has a density of 4.19 g / cc to 4.46 g / cc as measured according to ASTM B962-17.

[0027] Embodiment 16. A multi-layer sintered ceramic body according to any of the preceding embodiments, wherein the at least one second layer comprises zirconium oxide in an amount of 16 volume % and has a density of approximately 4.32 g / cc as measured according to ASTM B962-17.

[0028] Embodiment 17. The multilayer sintered ceramic body of Embodiment 20, wherein the at least one second layer has a thermal conductivity of 6.98×10 -6 / ℃ to 9.26×10 -6 / ℃ coefficient of thermal expansion (CTE).

[0029] Embodiment 18. The multilayer sintered ceramic body of any one of Embodiments 19 to 21, wherein the at least one second layer has a sintering resistance of 7×10 -4 and smaller dielectric loss.

[0030] Embodiment 19. The multilayer sintered ceramic body according to any one of the preceding embodiments, wherein the at least one second layer has a total impurity content of 5 ppm to 200 ppm relative to the mass of the at least one second layer as measured using an ICPMS method.

[0031] Embodiment 20. A multilayer sintered ceramic body according to any one of the preceding embodiments, wherein the at least one first layer has a thickness d1, the at least one second layer has a thickness d2, and the at least one third layer has a thickness d3, wherein the thickness d2 of the at least one second layer is 60% to 85% of the total thickness of the at least one first layer, the at least one second layer and the at least one third layer.

[0032] Embodiment 21. A method for preparing a multilayer sintered ceramic body, the method comprising the steps of: a) combining powders comprising yttrium oxide and aluminum oxide to prepare a first powder mixture; b) combining aluminum oxide powder with at least one of partially stabilized zirconium oxide powder and stabilized zirconium oxide powder to prepare a second powder mixture; c) combining aluminum oxide powder, yttrium oxide powder and at least one of unstabilized zirconium oxide powder, partially stabilized zirconium oxide powder and stabilized zirconium oxide powder to prepare at least one third powder mixture; d) applying heat to raise the temperature of at least one of the first powder mixture, the second powder mixture and the third powder mixture to a calcination temperature and maintaining the calcination temperature to perform calcination. calcining at least one of the powder mixtures to form at least one of a first calcined powder mixture, a second calcined powder mixture, and a third calcined powder mixture; e) separately arranging the first powder mixture, the second powder mixture, and the third powder mixture in an interior volume defined by a tool set of a sintering apparatus to form at least one layer of the first powder mixture, at least one layer of the second powder mixture, and at least one layer of the third powder mixture, and creating a vacuum condition within the volume, wherein the tool set includes a mold, the mold includes a sidewall, the sidewall includes an inner wall and an outer wall, wherein the inner wall has a diameter defining the interior volume capable of receiving the powder and an upper punch and a lower punch operably coupled to the die, wherein each of the upper punch and the lower punch has an outer wall defining a diameter that is smaller than the diameter of the inner wall of the die, thereby defining a gap between each of the upper punch and the lower punch and the inner wall of the die when at least one of the upper punch and the lower punch moves within the interior volume of the die, wherein the gap is 10 μm to 100 μm wide; f) applying pressure to the layers of the first powder mixture, the second powder mixture, and the third powder mixture while heating to a sintering temperature and sintering to form the multilayer sintered ceramic body, wherein the layers of the first powder mixture said at least one layer forming at least one first layer, said at least one layer of the second powder mixture forming at least one second layer, and said at least one layer of the third powder mixture forming at least one third layer; and g) lowering the temperature of the multilayer sintered ceramic body, wherein the at least one first layer comprises polycrystalline YAG, and the at least one second layer comprises aluminum oxide, wherein the aluminum oxide comprises at least one of stabilized zirconium oxide and partially stabilized zirconium oxide, and the at least one third layer comprises yttrium oxide, aluminum oxide, and at least one of unstabilized zirconium oxide, stabilized zirconium oxide, and partially stabilized zirconium oxide, wherein the at least one second layer is disposed between the at least one first layer and the at least one third layer.

[0033] Embodiment 22. The method of embodiment 21, wherein the first powder mixture, the second powder mixture, and the third powder mixture have a combined total impurity content of 200 ppm and less as measured using ICPMS.

[0034] Embodiment 23. A method according to embodiment 21 or 22, wherein the second powder mixture comprises partially stabilized zirconia or stabilized zirconia in an amount of not less than 15% and not more than 34% by weight relative to the weight of the second powder mixture.

[0035] Embodiment 24. The method of any one of Embodiments 21 to 23, wherein the first powder mixture, the second powder mixture, and the third powder mixture are crystalline as determined by x-ray diffraction.

[0036] Embodiment 25. The method of any one of Embodiments 21 to 24, wherein the second powder mixture comprises partially stabilized zirconia.

[0037] Embodiment 26. The method of any one of Embodiments 21 to 25, wherein the second powder mixture comprises yttria partially stabilized zirconia.

[0038] Embodiment 27. The method of any one of Embodiments 21 to 26, wherein the second powder mixture comprises 3 mol% yttria partially stabilized zirconia.

[0039] Embodiment 28. A method according to any one of Embodiments 21 to 27, wherein the pressure applied to the at least one first layer, the at least one second layer and the at least one third layer of the first powder mixture, the second powder mixture and the third powder mixture is 5 MPa to 100 MPa.

[0040] Embodiment 29. The method of any one of Embodiments 21 to 28, wherein the temperature of the calcining step is 600°C to 1200°C.

[0041] Embodiment 30. The method of any one of Embodiments 21 to 29, wherein the sintering temperature is from 1000°C to 1700°C.

[0042] Embodiment 31. A method according to any one of Embodiments 21 to 30, further comprising the steps of: h) optionally annealing the multilayer sintered ceramic body by applying heat to raise the temperature of the multilayer sintered ceramic body to an annealing temperature for annealing; and i) reducing the temperature of the annealed multilayer sintered ceramic body.

[0043] Embodiment 32. A method according to any one of Embodiments 21 to 31, further comprising the step of: j) machining the multilayer sintered ceramic body to form a multilayer sintered ceramic part in the shape of a window, a cover, a dielectric window, an RF window, a ring, a focusing ring, a processing ring, a deposition ring, a nozzle, an injector, a gas injector, a showerhead, a gas distribution plate, a diffuser, an ion suppressor element, a suction cup, an electrostatic wafer suction cup (ESC) and a positioning plate.

[0044] Embodiment 33. A multi-layer sintered ceramic body prepared by the method according to any one of Embodiments 21 to 32.

[0045] Embodiment 34. The multi-layer sintered ceramic body of Embodiment 33, wherein the multi-layer sintered ceramic body has a maximum dimension of 100 mm to about 625 mm.

[0046] The embodiments of the present invention may be used alone or in combination with each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The present disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not to scale. Instead, the dimensions of the various features are arbitrarily expanded or reduced for clarity. The drawings include the following figures:

[0048] Figure 1 A laminated structure as known in the art is shown;

[0049] Figure 2 A laminated structure as known in the art is shown;

[0050] Figure 3 showing the CTE difference between at least one phase of YAG, spinel, and yttria / zirconia (depicted as Y / Zr) compared to alumina over a range of temperatures;

[0051] Figure 4 An overall multilayer structure having mismatched CTE values ​​between at least one first layer and at least one second layer is shown;

[0052] Figure 5 SEM micrographs depicting interfaces of laminate structures as known in the art;

[0053] Figure 6 depicts an exemplary schematic diagram of a multilayer sintered ceramic body according to embodiments as disclosed herein;

[0054] Figure 7 shows a change in CTE of at least one second layer 102 comprising zirconium oxide in alumina according to embodiments as disclosed herein;

[0055] Figure 8 shows x-ray diffraction results of at least one second layer 102 according to embodiments as disclosed herein;

[0056] Figure 9a ), Figure 9b )and Figure 9c ) depicts the change in CTE of a multilayer sintered ceramic body comprising a composition comprising at least one first layer and at least one second layer comprising YAG according to embodiments as disclosed herein;

[0057] Figure 10 The yttria / alumina two-component phase diagram is depicted;

[0058] Figure 11 a) depicts a SEM micrograph of the surface of at least one first layer 100 comprising polycrystalline YAG, obtained using the backscatter detection (BSD) method, and Figure 11 b) depicts an SEM image of the same area from the surface after threshold switching to reveal porosity and an alumina phase, according to embodiments as disclosed herein;

[0059] Figure 12 a) depicts Figure 11 a topographical SEM micrograph (using a topography imaging method) of a surface of at least one first layer comprising YAG and Figure 12 b) depicts a topographic SEM image of the same area from the surface after threshold switching to reveal porosity and an alumina phase according to embodiments as disclosed herein;

[0060] Figure 13 shows x-ray diffraction results of at least one first layer 100 comprising YAG according to embodiments as disclosed herein;

[0061] Figure 14 The relationship between pore area and pore size is shown for a monolithic multi-layer sintered ceramic body comprising: at least one first layer 100 comprising YAG and at least one second layer 102 comprising about 16 volume % zirconia;

[0062] Figure 15 shows cumulative pore area versus pore size for a multilayer sintered ceramic body comprising: at least one first layer 100 comprising YAG and at least one second layer 102 comprising about 16 volume percent zirconium oxide with the balance being aluminum oxide, according to embodiments as disclosed herein;

[0063] Figure 16 a) depicts an SEM micrograph of a surface of at least one layer comprising YAG of a multilayer sintered ceramic body, and Figure 16 b) shows the Figure 14 and Figure 15 Total % of surface area containing porosity within the 7 images.

[0064] Figure 17a ), Figure 17b )and Figure 17c ) depicts the change in CTE of a multilayer sintered ceramic body comprising at least one first layer 100 and at least one second layer 102 comprising spinel according to embodiments as disclosed herein.

[0065] Figure 18 shows x-ray diffraction results of a calcined powder mixture of a composition forming at least one first layer 100 comprising magnesium aluminate spinel;

[0066] Figure 19 depicts an SEM micrograph of a surface of at least one first layer 100 comprising magnesium aluminate spinel according to embodiments as disclosed herein;

[0067] Figure 20a ), Figure 20b )and Figure 20c ) depicts the change in CTE of a monolithic multilayer sintered ceramic body according to an embodiment as disclosed herein, the monolithic multilayer sintered ceramic body comprising an embodiment of at least one first layer 100 and at least one second layer 102, the at least one first layer comprising at least one crystalline phase of a ceramic material comprising yttria and zirconia.

[0068] Figure 21 a) shows the nonlinear interface 104 of the monolithic multilayer sintered ceramic body, and Figure 21 b) depicts a 500x SEM image of a surface of at least one first layer 100 comprising about 20 mol% zirconium oxide and about 80 mol% yttrium oxide according to embodiments as disclosed herein;

[0069] Figure 22 a) depicts a schematic diagram of a multilayer sintered ceramic body 98, and Figure 22 b) shows an enlarged schematic diagram illustrating the nonlinear interface 104 and the second interface 105 according to an embodiment as disclosed herein;

[0070] Figure 23 a) shows the tortuosity (T) and Figure 23 b) depicting an average interface line (IL) characterizing the nonlinear interface 104 according to embodiments as disclosed herein;

[0071] Figure 24a) depicts a 5000x SEM micrograph of a nonlinear interface 104 of a multilayer sintered ceramic body, and Figure 24 b) shows the measurement results of the tortuosity (T) of the nonlinear interface 104 according to embodiments as disclosed herein;

[0072] Figure 25 a) shows the number of grains per unit interface length (in μm) of the nonlinear interface 104, and Figure 25 b) depicts the tortuosity (T) of the nonlinear interface 104 according to embodiments as disclosed herein;

[0073] Figure 26 a) and Figure 26 b) SEM micrographs at 1000x (and 5000x) showing at least one third layer of a multi-layer sintered ceramic body as disclosed herein;

[0074] Figure 27 a) Figure 27 b) and Figure 27 c) illustrates an exemplary cross-sectional view of an embodiment of a multilayer sintered ceramic body as disclosed herein before and after a machining process to form a multilayer sintered component including through-holes 112 according to an embodiment as disclosed herein;

[0075] Figure 28 depicts a schematic diagram of a tool set of a pressure-assisted sintering apparatus according to embodiments as disclosed herein;

[0076] Figure 29 shows a cross-sectional view of an SPS sintering apparatus having a tool set located in a vacuum chamber (not shown), the SPS sintering apparatus having a simple arrangement for sintering ceramic material;

[0077] Figure 30A Shown Figure 29 embodi ment, showing a foil layer;

[0078] Figure 30B Shown Figure 29 An alternative embodiment showing two foil layers;

[0079] Figure 30C Shown Figure 29 Another alternative embodiment of , showing three foil layers;

[0080] Figure 31A and Figure 31B yes Figure 29 Top view of the SPS sintering equipment;

[0081] Figure 32is a graph depicting radial variation of the average coefficient of thermal expansion (CTE) of graphite materials A and B at 1200° C.; and

[0082] Figures 33 to 34 Semiconductor plasma processing systems 9500 and 9600 are depicted. DETAILED DESCRIPTION

[0083] The following detailed description assumes that the present disclosure is implemented in equipment (such as an etching chamber or a deposition chamber) that is necessary as part of manufacturing a device on a semiconductor wafer substrate. However, the present invention is not limited to this. The workpiece can have various shapes, sizes, and materials. In addition to semiconductor wafer processing, other workpieces that can utilize embodiments of the present invention include various articles, such as fine feature size inorganic circuit boards, magnetic recording media, magnetic recording sensors, mirrors, optical elements, micromechanical devices, etc.

[0084] Corrosion-resistant ceramics, particularly multilayer sintered ceramic bodies having more than one layer, and their preparation are described herein for use as components in semiconductor reaction chambers. Semiconductor etching and deposition reactors require reactor components having surfaces that are highly resistant to corrosion and erosion by the halogen-containing plasmas necessary for processing. These surfaces preferably minimize the release of particles from the component surfaces into the chamber. In addition, the chamber components must have sufficient mechanical strength for handling and use, especially when the component sizes are large (e.g., >100 mm in diameter). Sintered ceramic bodies can be machined into sintered components and, therefore, must be capable of being handled and machined in large sizes while providing corrosion resistance, low particle generation, and high mechanical strength. The sintered ceramic body as disclosed herein comprises at least one first layer having at least one polycrystalline ceramic material comprising a garnet structure having a composition comprising yttrium oxide and aluminum oxide in a ratio of about 3:5 of the formula Y3Al5O 12 YAG (yttrium aluminum oxide or yttrium aluminate), spinel (magnesium aluminate spinel, MgAl2O4), and yttrium oxide and zirconium oxide, wherein the zirconium oxide is present in the yttrium oxide in an amount of not less than 10 mol% ZrO2 and not more than 25 mol% ZrO2. These materials have excellent corrosion and erosion resistance. The use of these materials produces semiconductor plasma processing chamber components having surfaces that provide improved plasma resistance compared to other materials when subjected to halogen-based plasma etching and deposition conditions.

[0085] In one embodiment, a multilayer sintered ceramic body is described herein, comprising: at least one first layer comprising a polycrystalline ceramic material selected from the group consisting of YAG, magnesium aluminate spinel, and yttria and zirconia, wherein the zirconia is present in an amount not less than 10 mol% and not more than 25 mol%; at least one second layer comprising alumina and zirconia, wherein the zirconia comprises at least one of stabilized zirconia and partially stabilized zirconia; and at least one third layer comprising at least one selected from the group consisting of YAG, alumina, and zirconia, wherein the at least one second layer is disposed between the at least one first layer and the at least one third layer, wherein the absolute value of the difference in coefficient of thermal expansion (CTE) between the at least one first layer, the at least one second layer, and the at least one third layer, as measured according to ASTM E228-17, is from 0 to 0.75×10 -6 / °C, and wherein the at least one first layer, the at least one second layer and the at least one third layer form an integrally sintered ceramic body.

[0086] As the semiconductor manufacturing industry moves toward larger semiconductor substrate diameters, larger chamber components (approximately 100 mm to approximately 625 mm in diameter) are required. Therefore, the multilayer sintered ceramic bodies disclosed herein must possess sufficient strength to avoid breakage during use and handling. The multilayer sintered ceramic bodies disclosed herein also include at least one second layer comprising zirconium oxide and aluminum oxide, the at least one second layer having high mechanical strength and also having preferred electrical and material properties as disclosed below.

[0087] refer to Figure 6 , discloses a multilayer sintered ceramic body 98 having at least one first layer 100, the at least one first layer being the outermost layer, having a plasma-facing surface 106 that provides resistance to the corrosive and erosive effects of halogen-based plasmas and ion bombardment, a controlled porosity distribution at small pore sizes, high purity, high density, and low surface roughness. Preferably, the at least one first layer 100 has a coefficient of thermal expansion (CTE) that differs from the CTE of the at least one second layer 102 and the at least one third layer 103 by an amount of 0 to 0.75×10 -6 / °C (in absolute terms). In some embodiments, the CTE of at least one first layer and at least one second layer are substantially the same. In addition, the multilayer sintered ceramic body 98 according to embodiments of the present disclosure includes a nonlinear interface 104 defined by at least one first layer 100 and at least one second layer 102 (see Figure 21 ), whereby the nonlinear interface 104 can provide enhanced adhesion between these layers.

[0088] Embodiments of the present disclosure also relate to specific multi-layer sintered ceramic bodies comprising at least one second layer 102 having a composition range comprising zirconium oxide and aluminum oxide. Within the composition range of yttria and zirconium oxide, the at least one second layer 102 exhibits high mechanical strength, enhanced hardness (Young's modulus), high thermal conductivity, low dielectric loss, a high dielectric constant, and a coefficient of thermal expansion (CTE) that matches the at least one first layer 100 and the at least one third layer 103 within the disclosed range.

[0089] The at least one third layer 103 comprises multiple phases of at least one of YAG, alumina, and zirconia, thereby providing improved machinability. The at least one third layer 103 can provide a sintering profile similar to that of the at least one first layer 100, thereby providing greater uniformity within these layers during sintering. The CTE of the at least one third layer 103 matches the CTE of the at least one first layer and the at least one second layer within the ranges disclosed herein.

[0090] At least one first layer, at least one second layer, and at least one third layer having CTE values ​​within the ranges disclosed herein provide for the preparation of large-sized (100 mm to about 625 mm) monolithic multilayer sintered bodies and chamber components made therefrom. Furthermore, methods for preparing such corrosion-resistant multilayer sintered ceramics and their use in plasma processing chambers are disclosed.

[0091] Definitions—As used herein, the following terms are defined as follows: “alumina” shall be understood to mean aluminum oxide comprising Al 2 O 3 , “zirconia” shall be understood to mean zirconium oxide comprising ZrO 2 , and “yttria” shall be understood to mean yttria comprising Y 2 O 3 .

[0092] As used herein, the terms "semiconductor wafer," "wafer," "substrate," and "wafer substrate" may be used interchangeably. Wafers or substrates used in the semiconductor device industry typically have a diameter of 200 mm, or 300 mm, or 450 mm.

[0093] As used herein, the term "sintered ceramic body" is synonymous with "multilayer sintered ceramic body," "multilayer corrosion-resistant ceramic," "corrosion-resistant body," "sintered ceramic," "multilayer monolith," and similar terms, and refers to a monolithic, unitary sintered ceramic article formed by co-compacting more than one powder mixture by applying pressure and heat, which produces a monolithic, dense, multilayer sintered ceramic body. The monolithic, multilayer sintered ceramic body can be machined into a monolithic, multilayer sintered ceramic component that can be used as a chamber component in plasma processing applications. Thus, the multilayer sintered ceramic bodies disclosed herein are not formed by laminating preformed layers together, i.e., the multilayer sintered ceramic bodies disclosed herein are not laminated materials.

[0094] As used herein, the term "co-compacting" or "co-compaction" refers to a process in which at least two loose powder materials are placed in a mold and subjected to pressure to form a powder compact. The powder compact is free of binders, dispersants, and other similar organic substances commonly used in the art to form green or shaped bodies or tapes.

[0095] "Integral" or "unitary" means a single piece or single-piece part that is complete in itself without additional parts, ie, the part is a single piece that is formed as a unit with another part.

[0096] The term "substantially" as used in this document is a descriptive term indicating approximation and means "to a considerable extent" or "to a large extent but not entirely as specified" and is intended to avoid strict numerical boundaries of specified parameters.

[0097] As used herein, the term "sintered ceramic component" or "multilayer sintered ceramic component" refers to a sintered ceramic body, a multilayer sintered ceramic body, or a corrosion-resistant ceramic after a machining step to form the ceramic into a specific shape for a desired component in a semiconductor processing chamber as disclosed herein.

[0098] As used herein, the term "powder mixture" means one or more starting powders that are mixed together prior to the sintering process, from which these powders form at least one layer of a multilayer sintered ceramic body after the sintering step.

[0099] The term "annealing," as applied to heat treatment of ceramics, is understood herein to mean heat treating the disclosed multi-layer sintered ceramic bodies in air to relieve stress and / or normalize stoichiometry.

[0100] As used herein, the term "tool set" is a tool set that may include at least a die and at least two punches. When fully assembled, the tool set defines a volume for placing the disclosed powder mixture.

[0101] As used herein, the term "phase" is understood to mean a distinct crystalline region, portion, or layer of a sintered ceramic body having a particular crystal structure.

[0102] As used herein, a "solid solution" is defined as a mixture of different elements having the same crystal lattice structure. The mixture within the lattice can be substitutional, where atoms from one starting crystal replace atoms from another starting crystal, or interstitial, where atoms occupy positions that are normally vacant in the lattice.

[0103] As used herein, the term "nanopowder" is intended to encompass nanopowders with a specific surface area greater than 20 m 2 / g of those powders.

[0104] As used herein, the term "phase" is understood to mean a distinct crystalline region, portion, or layer of a sintered ceramic body having a particular crystal structure.

[0105] As used herein, the term "layer" is understood to mean a thickness of material, typically one of several. The material may be, for example, a ceramic powder, a powder mixture, a calcined powder mixture, or a sintered region or portion.

[0106] As used herein, "ambient temperature" refers to a temperature range of about 22°C to 25°C.

[0107] As used herein, the term "purity" refers to the absence of various contaminants a) in the starting materials from which the powder mixture may be formed, b) in the processed powder mixture (or calcined powder mixture), and c) in the multilayer sintered ceramic body or component as disclosed herein. Higher purities (approaching 100%) indicate a material that is substantially free of contaminants or impurities, or has very low amounts of contaminants or impurities, and that substantially comprises the composition of materials present in the disclosed starting powders.

[0108] As used herein, the term "impurities" refers to compounds / contaminants present in a powder or sintered ceramic other than the intended compounds themselves (starting powders of magnesium oxide, aluminum oxide, yttrium oxide, and zirconium oxide, stabilizing compounds (if applicable), powder mixtures formed therefrom, and ceramics). Impurities can be present in the starting powders, powder mixtures, processed powder mixtures, and sintered ceramic bodies. The impurity content of the powders, powder mixtures, and first and second layers of the sintered bodies disclosed herein was determined using ICPMS.

[0109] As used herein, the term "dopant" is a substance added to a bulk material to produce desired properties in a ceramic material (e.g., to alter electrical properties). Typically, if used, dopants are present in low concentrations, i.e., >0.002 wt% to <0.05 wt%.

[0110] Impurities differ from dopants in that dopants, as defined herein, are compounds that are intentionally added to the starting powder or powder mixture to achieve certain electrical, mechanical, optical, or other properties, such as particle size modification, in the multilayer sintered ceramic body. The term "dopant" as used herein does not include Hf and Y, as included in the zirconia starting material, as long as they can be retained in the multilayer sintered ceramic body.

[0111] As used herein, the term "sintering aid" refers to compounds that enhance densification and thereby reduce porosity during sintering, such as silicon dioxide (SiO2), lithium oxide (Li2O), lithium fluoride (LiF), magnesium oxide (MgO), and / or calcium oxide (CaO). The Hf and Y present in the starting powder, and the extent to which they remain in the sintered ceramic, do not include sintering aids, impurities, or dopants as defined herein.

[0112] As used herein, the terms "about" and "approximately" used in connection with numbers or features as disclosed herein allow for a variance of plus or minus 10%.

[0113] As used herein, the term "coefficient of thermal expansion (CTE)" is measured in accordance with ASTM E228-17 over a temperature range of 25°C to 200°C to 25°C to 1400°C, preferably 25°C to 1200°C, more preferably 25°C to 1000°C, more preferably 25°C to 800°C, more preferably 25°C to 600°C, more preferably 25°C to 400°C, and more preferably 25°C to 200°C. CTE describes how the size of an object changes as temperature changes. Specifically, CTE measures the fractional size change per degree of temperature change at constant pressure. To determine this coefficient at a certain temperature, the volume of the material is measured at a reference temperature and the volume of the material is measured at the temperature for which the CTE is desired to be determined. The fractional change is then determined based on the difference in volume and temperature.

[0114] All CTE values ​​disclosed herein are derived according to ASTM E228-17. In particular, the reference temperature used is ambient temperature, in particular 25°C. Thus, if a CTE is disclosed for a given temperature (i.e., 200°C), the CTE has been determined by comparing the volume (or linear expansion of an isotropic material) at that temperature with the volume (or linear expansion of an isotropic material) at ambient temperature (in particular, 25°C). In any case of conflicting information regarding the CTE, ASTM E228-17 always governs the disclosure. In the examples disclosed, the CTE is measured using a vertical dilatometer, in particular the model L75 available from Linseis Messgeraete GmbH of Selb, Germany.

[0115] During semiconductor device processing, corrosion-resistant chamber components are used within etch and / or deposition chambers and are exposed to harsh corrosive and erosive environments that cause particle release into the chamber, leading to yield loss due to wafer-level contamination. The multilayer sintered ceramic bodies disclosed herein and related components fabricated therefrom provide improved plasma tolerance, thermal conductivity, and enhanced mechanical strength for use within semiconductor processing chambers through specific material properties and characteristics described below.

[0116] According to one embodiment, disclosed herein is a multilayer sintered ceramic body comprising at least one first layer comprising a polycrystalline phase of a ceramic material selected from the group consisting of YAG, magnesium aluminate spinel, and yttria and zirconia, wherein the zirconia is present in an amount of not less than 10 mol% and not more than 25 mol%; at least one second layer comprising alumina, wherein the alumina comprises at least one of stabilized zirconia (SZ) and partially stabilized zirconia (PSZ); and at least one third layer comprising multiple phases of at least YAG, alumina, and zirconia, wherein the absolute value of the difference in coefficient of thermal expansion (CTE) between the at least one first layer, the at least one second layer, and the at least one third layer is 0 to 0.75×10-6 / °C (as measured according to ASTM E228-17), wherein the at least one first layer, the at least one second layer, and the at least one third layer form an integral multilayer sintered ceramic body.

[0117] In one embodiment, the layers exhibit a certain absolute value of the CTE difference between the at least one first layer, the at least one second layer and the at least one third layer, such as in the temperature range of 25°C to 1700°C or in the temperature range of 200°C to 1400°C according to ASTM E228-17, the absolute value is 0 to 0.75×10-6 / °C, preferably 0 to 0.7×10-6 / °C, preferably 0 to 0.6×10-6 / °C, preferably 0 to 0.5×10-6 / °C, preferably 0 to 0.45×10-6 / °C, preferably 0 to 0.4×10-6 / °C, preferably 0 to 0.35×10-6 / °C, preferably 0 to 0.3×10-6 / °C, preferably 0 to 0.25×10-6 / °C, preferably 0 to 0.2×10-6 / °C, preferably 0 to 0.15×10-6 / °C, preferably 0 to 0.1×10-6 / °C, preferably 0 to 0.08×10-6 / °C, preferably 0 to 0.04×10-6 / °C, and preferably 0 to 0.02×10-6 / °C. These ranges of absolute values ​​of the CTE differences between the at least one first layer, the at least one second layer, and the at least one third layer correspond to CTE differences of about 10% and less, preferably 9% and less, preferably 8% and less, preferably 6% and less, preferably 4% and less, preferably 3% and less, preferably 2.5% and less, preferably 2% and less, preferably 1.5% and less, preferably 1% and less, preferably 0.5% and less, and preferably 0.25% and less between any of the at least one first layer, the at least one second layer, and the at least one third layer, as a percentage (as measured relative to the at least one first layer 100). When the CTE between the at least one first layer 100, the at least one second layer 102, and the at least one third layer 103 varies within these ranges, and more specifically, when the CTE between the at least one first layer, the at least one second layer, and the at least one third layer varies within these ranges, as measured according to ASTM E228-17, across a temperature range from ambient temperature to about 1700°C (or, as depicted in the accompanying figures, from about 200°C to about 1400°C), the pressure-assisted method disclosed herein can be used to form a monolithic, multi-layer sintered ceramic body, particularly one having large dimensions (>100 mm to about 625 mm), high strength, and high interlayer adhesion. Due to the isotropic nature of the ceramic materials comprising the at least one first layer, the at least one second layer, and the at least one third layer disclosed herein, the coefficient of thermal expansion (CTE) as used herein may refer interchangeably to linear or volume CTE. It is preferred that the CTE difference between the at least one first layer, the at least one second layer, and the at least one third layer be minimized to reduce interlayer interfacial stress.CTE differences between the at least one first layer, the at least one second layer, and the at least one third layer that are greater than the CTE differences disclosed herein may result in fracture and / or cracking of the multilayer sintered ceramic body.

[0118] refer to Figure 6 , depicts a schematic diagram of a multilayer sintered ceramic body 98 as disclosed herein, wherein 100 represents at least one first layer having a thickness d1, 102 shows at least one second layer 102 having a thickness d2, and 103 shows at least one third layer 103 having a thickness d3. The multilayer sintered ceramic body 98 produced according to the method as disclosed herein (depicting at least one first layer 100, wherein the first layer has a thickness; a second layer 102, wherein the second layer has a thickness; and a third layer 103, wherein the third layer has a thickness) preferably has a thickness of the second layer 102 that is 70% to 95%, preferably 70% to 90%, preferably 70% to 85%, preferably 80% to 95%, preferably 85% to 95%, of the total thickness of the three layers 100, 102, and 103.

[0119] The at least one second layer 102 provides mechanical strength as well as electrical properties of a low dielectric loss tangent (less than 7×10-4 at 1 MHz) and a high dielectric constant of about 12. Therefore, in some embodiments, it may be preferred to maximize the thickness d2. In order to provide a combination of high mechanical strength and stiffness with machinability to form a sintered ceramic component from a multilayer sintered body as disclosed herein, as Figure 6The thickness d2 of the at least one second layer 102 depicted in the figure is preferably greater than each of the thickness d1 of the at least one first layer 100 and / or the thickness d3 of the at least one third layer 103. The thickness d1 of the at least one first layer 100 and / or the thickness d3 of the at least one third layer 103 can each be 0.5 mm to 5 mm, preferably 0.5 mm to 4 mm, preferably 0.5 mm to 3 mm, preferably 0.5 mm to 2 mm, preferably 0.5 mm to 1 mm, preferably 0.75 mm to 5 mm, preferably 0.75 mm to 3 mm, preferably 1 mm to 5 mm, preferably 1 mm to 4 mm, preferably 1 mm to 3 mm. The total thickness (d1+d2+d3) of the multilayer sintered ceramic body as disclosed herein can be from about 5 mm to about 50 mm, preferably from about 5 mm to about 40 mm, preferably from about 5 mm to about 35 mm, preferably from about 5 mm to about 33 mm, preferably from about 5 mm to about 30 mm, preferably from about 8 mm to about 25 mm, and preferably from about 10 mm to about 20 mm. In certain embodiments where it may be desirable to minimize the thickness d1 of at least one first layer 100 and / or the thickness (d3) of at least one third layer 103, the multilayer sintered ceramic body may be machined after sintering and / or after annealing to reduce the thickness d1 and / or d3 of layers 100 and / or 103, thereby changing the electrical properties of the multilayer sintered ceramic body 98 or a component formed therefrom, such as dielectric loss, dielectric constant, thermal conductivity, or other properties.

[0120] The multi-layer sintered ceramic body disclosed herein has at least one first layer 100, wherein the at least one first layer has a thickness; at least one second layer 102, wherein the at least one second layer has a thickness; and at least one third layer 103, wherein the at least one third layer has a thickness, wherein the thickness of the at least one second layer 102 is 70% to 95%, preferably 70% to 90%, preferably 70% to 85%, preferably 80% to 95%, preferably 85% to 95% of the total thickness of the three layers 100, 102 and 103, respectively.

[0121] In certain embodiments, the thickness d2 of the at least one second layer is 60% to 85%, preferably 60% to 80%, preferably 60% to 75%, preferably 60% to 70%, preferably 70% to 85%, preferably 75% to 85%, preferably 70% to 80%, preferably 70% to 75%, of the total thickness (d1 + d2 + d3) of the at least one first layer, the at least one second layer, and the at least one third layer. The at least one first layer having a thickness d1 includes a plasma-facing surface 106 that provides corrosion and erosion resistance to halogen-based plasmas. In embodiments, the thickness d1 of the at least one first layer is 0.75% to 20%, preferably 0.75% to 15%, preferably 0.75% to 12%, preferably 3% to 20%, preferably 5% to 20%, preferably 3% to 15%, preferably 5% to 12%, of the total thickness (d1 + d2 + d3) of the at least one first layer, the at least one second layer, and the at least one third layer.

[0122] The stresses generated by layers comprising materials with mismatched CTEs can affect the mechanical strength and integrity of the multilayer sintered ceramic body. Thus, if the difference in absolute CTE values ​​between the at least one first layer 100, the at least one second layer 102, and the at least one third layer 103 of the sintered ceramic body is too great, at least one layer of the multilayer sintered ceramic body may crack, warp, and / or break when performing the steps of the method disclosed herein. This CTE difference is important at all process temperatures, especially at high temperatures, such as those experienced during sintering, annealing, and cooling, where the CTE difference can generate significant interfacial stresses between the layers of the sintered body. Therefore, in order to form a multilayer monolithic sintered ceramic body having high mechanical strength, high adhesion strength between the layers, and sufficient handleability (without cracking or breakage), the CTE difference between the at least one first layer 100, the at least one second layer 102, and the at least one third layer 103 of the multilayer sintered ceramic body is preferably within the disclosed ranges and further matched as closely as possible. In a preferred embodiment, at least one first layer, at least one second layer, and at least one third layer may have respective CTEs that are the same or substantially the same in absolute value over a temperature range from ambient temperature (or about 200° C. as disclosed in the accompanying drawings) to about 1700° C. (or at least to 1400° C. as depicted in the accompanying drawings) according to the disclosed methods. As used herein, the term “CTE matching” refers to a combination of at least one first layer 100, at least one second layer 102, and at least one third layer 103, whose CTEs differ by a value within the disclosed preferred range (an absolute value of 0 to about 0.75×10 -6According to one embodiment, the at least one first layer 100 may comprise a polycrystalline phase of a ceramic material selected from the group consisting of YAG, magnesium aluminate spinel, and yttria and zirconia, wherein the zirconia is present in an amount of not less than 10 mol% ZrO2 and not more than 25 mol% ZrO2, whereby the at least one first layer 100 is CTE matched with the at least one second layer 102 (comprising alumina and at least one of stabilized zirconia and partially stabilized zirconia) and the at least one third layer 103 (comprising a combination of the at least one first layer and the at least one second layer) to form a unitary multi-layer sintered ceramic body. On a percentage basis, the combination of at least one first layer 100, at least one second layer 102, and at least one third layer 103 may have CTE values ​​(within the temperature range as disclosed herein) that match each other by a percentage (as measured relative to the at least one first layer 100) of about 10% and less, preferably 9% and less, preferably 8% and less, preferably 6% and less, preferably 4% and less, preferably 3% and less, preferably 2.5% and less, preferably 2% and less, preferably 1.5% and less, preferably 1% and less, preferably 0.5% and less, and preferably 0.25% and less of the at least one first layer, at least one second layer, and at least one third layer.

[0123] Can be based on Figure 7 The composition of the at least one second layer 102 is selected to produce a specific CTE characteristic based on the volume % of zirconium oxide in aluminum oxide depicted, Figure 7 Exemplary CTE results are shown for at least one second layer 102 as disclosed herein, wherein the second layer comprises zirconium oxide in an amount of 10% to 30% by volume, with the balance comprising Al 2 O 3. The amount of zirconium oxide and the resulting CTE value of the at least one second layer 102 are preferably CTE-matched to the at least one first layer and the at least one third layer over a temperature range corresponding to the process from ambient temperature (or 200° C. according to the accompanying drawings) to about 1700° C. (or 1400° C. according to the accompanying drawings) to produce a monolithic multi-layer sintered body as disclosed herein.

[0124] According to one embodiment, the at least one second layer 102 comprises aluminum oxide and zirconium oxide, wherein the zirconium oxide comprises at least one of stabilized zirconium oxide and partially stabilized zirconium oxide in an amount by volume of 5% to 30%, preferably 5% to 25%, preferably 5% to 20%, preferably 5% to 16%, preferably 10% to 30%, preferably 16% to 30%, preferably 10% to 25%, and preferably 15% to 20% relative to the volume of the at least one second layer (and the balance comprises Al2O3). These volume percentages of the at least one second layer 102 correspond to a weight percentage of the second powder mixture comprising zirconium oxide (and the balance being aluminum oxide) of about 7% to about 40%, preferably about 7% to about 35%, preferably about 7% to about 28%, preferably about 7% to about 23%, preferably about 15% to about 40%, preferably about 23% to about 40%, preferably about 15% to about 34%, preferably about 21% to about 28%, and preferably about 23%. Within this composition and temperature range, the coefficient of thermal expansion (CTE) of the at least one second layer 102 can vary between the at least one second layer 102 comprising 5 volume percent zirconia and having a CTE of 6.8×10-6 / ° C. measured at 200° C. and the at least one second layer 102 comprising approximately 30 volume percent zirconia and having a CTE of approximately 9.75×10-6 / ° C. measured at 1400° C. The volumetric amount of at least one of stabilized zirconia or partially stabilized zirconia in the at least one second layer 102 provides the ability to modify the CTE to be the same or substantially the same as the CTE of the at least one first layer 100 and the at least one third layer 103 and within the disclosed CTE matching range.

[0125] refer to Figure 7 The coefficient of thermal expansion (CTE) of the at least one second layer 102 was measured using experimental data using dilatometry according to ASTM E228-17 for compositions of 10 volume %, 16 volume %, and 20 volume % ZrO2 (and the balance being alumina). As measured according to ASTM E228-17, the exemplary at least one second layer 102 comprising approximately 16 volume % zirconium oxide was measured to have a CTE of 6.98×10 -6 / ℃ to 9.26×10 -6 / ℃ coefficient of thermal expansion (CTE). Figure 8 As shown by the X-ray diffraction results of , at least one second layer 102 comprises at least two separate crystalline phases of zirconium oxide and aluminum oxide (referred to herein as a composite oxide or particulate composite material or zirconium oxide toughened alumina ZTA). Therefore, the CTE values ​​(e.g., 5 vol.%, 25 vol.%, and 30 vol.% zirconium oxide) were calculated using the volume mixing rule as known to those skilled in the art. Figure 7). The CTE value of at least one second layer (not shown) comprising 5 volume % zirconia as a function of temperature is generally between the range of pure alumina and the at least one second layer comprising 10 volume % zirconia. The ability to vary the CTE characteristics of the at least one second layer 102 provides CTE matching between the at least one second layer 102, the at least one third layer 103, and the at least one first layer 100, particularly within a temperature range consistent with the methods and sintering temperatures disclosed herein. The selection of the composition of the at least one second layer 102 and the at least one third layer 103 enables the use of a variety of materials for the at least one first layer 100 having the same or substantially the same CTE as the second layer 102 and the third layer 103 within the ranges disclosed herein, but is not limited thereto. In some embodiments, the CTE of the at least one second layer 102 may be greater than and less than the CTE of the at least one first layer within the disclosed temperature range from ambient temperature to about 1700°C (or from 200°C to 1400°C, as shown in the figures), such that the CTE difference is zero within this temperature range. In other embodiments, the CTE of the at least one second layer 102 may be greater than or less than the CTE of the at least one first layer 100 within the disclosed temperature range (as shown in the figures, from ambient temperature to about 1700° C., or from 200° C. to 1400° C.), and thus, the CTE of the at least one second layer 102 may be greater than or less than the CTE of the at least one first layer 100 within the disclosed temperature range, ... such as within the temperature range of 25° C. to 1700° C. or within the temperature range of 200° C. to 1400° C. according to ASTM The absolute value of the difference in coefficient of thermal expansion (CTE) between the at least one first layer 100 and the at least one second layer 102 measured by E228-17 may be 0.003×10-6 / °C to 0.75×10-6 / °C, preferably 0.003×10-6 / °C to 0.7×10-6 / °C, preferably 0.003×10-6 / °C to 0.6×10-6 / °C, preferably 0.003×10-6 / °C to 0.5×10-6 / °C, preferably 0.003×10-6 / °C to 0.45×10-6 / °C, preferably 0.003×10-6 / °C to 0.4×10-6 / °C, preferably 0.003×10-6 / °C to 0.35×10-6 / °C, preferably 0.003×10-6 / °C to 0. 3×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.25×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.2×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.15×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.1×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.08×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.06×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.04×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.02×10-6 / ℃, and preferably 0.003×10-6 / ℃ to 0.01×10-6 / ℃.

[0126] In other embodiments, the at least one second layer 102 may have a CTE greater than that of the at least one first layer 100 within a temperature range of from about 600° C. to about 1700° C. (or to at least 1400° C. as depicted in the figures), and a CTE less than that of the at least one first layer 100 within a temperature range of from ambient temperature (or to at least 200° C. as depicted in the figures) to about 600° C. The temperature at which the magnitude of the CTE change between the at least one first layer and the at least one second layer may occur at any temperature between about 200° C. and about 800° C. Without being bound by a particular theory, the lower CTE of the at least one second layer 102 relative to the at least one first layer 100 at lower temperatures (e.g., 800° C. to ambient temperature) serves to provide compression of the at least one first layer 100, thereby reducing the likelihood of crack propagation, fracture, and spalling, which may lead to particle generation during use as a component in a semiconductor plasma processing chamber.

[0127] The at least one third layer 103 typically has a CTE within the ranges disclosed for the at least one first layer and the at least one second layer. The CTE of the at least one third layer 103 can be adjusted to match the CTE of the at least one first layer and the at least one second layer by varying the amount of zirconium oxide. Thus, as measured in accordance with ASTM E228-17 over a temperature range of 25°C to 1700°C or over a temperature range of 200°C to 1400°C, the absolute value of the difference in coefficient of thermal expansion (CTE) between the at least one first layer 100, the at least one second layer 102, and the at least one third layer 103 may be, in some embodiments, 0 to 0.75×10-6 / °C, preferably 0 to 0.7×10-6 / °C, preferably 0 to 0.6×10-6 / °C, preferably 0 to 0.5×10-6 / °C, preferably 0 to 0.45×10-6 / °C, preferably 0 to 0.4×10-6 / °C, preferably 0 to 0.3 5×10-6 / ℃, preferably 0 to 0.3×10-6 / ℃, preferably 0 to 0.25×10-6 / ℃, preferably 0 to 0.2×10-6 / ℃, preferably 0 to 0.15×10-6 / ℃, preferably 0 to 0.1×10-6 / ℃, preferably 0 to 0.08×10-6 / ℃, preferably 0 to 0.06×10-6 / ℃, preferably 0 to 0.04×10-6 / ℃, preferably 0 to 0.02×10-6 / ℃, and preferably 0 to 0.01×10-6 / ℃.

[0128] In other embodiments, such as in the temperature range of 25°C to 1700°C or in the temperature range of 200°C to 1400°C according to ASTM The absolute value of the difference in coefficient of thermal expansion (CTE) between the at least one first layer 100, the at least one second layer 102 and the at least one third layer 103 measured by E228-17 may be 0.003×10-6 / °C to 0.75×10-6 / °C, preferably 0.003×10-6 / °C to 0.7×10-6 / °C, preferably 0.003×10-6 / °C to 0.6×10-6 / °C, preferably 0.003×10-6 / °C to 0.5×10-6 / °C, preferably 0.003×10-6 / °C to 0.45×10-6 / °C, preferably 0.003×10-6 / °C to 0.4×10-6 / °C, preferably 0.003×10-6 / °C to 0.35×10-6 / °C, preferably 0.003×10-6 / °C to 0.35×10-6 / °C, preferably 0.003×10-6 / °C to 0.6×10-6 / °C 6 / ℃ to 0.3×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.25×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.2×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.15×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.1×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.1×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0. 10-6 / ℃ to 0.08×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.06×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.04×10-6 / ℃, preferably 0.003×10-6 / ℃ to 0.02×10-6 / ℃, and preferably 0.003×10-6 / ℃ to 0.01×10-6 / ℃.

[0129] In contrast, Figure 4 A material combination prepared by the same method but not meeting the CTE matching requirements (and therefore the absolute value mismatch of the CTE difference) as disclosed herein is shown in FIG, which depicts a sintered ceramic body formed from a YAG first layer and an alumina substrate (second layer) (according to the "Comparative Example" in the Examples section). Figure 3As shown, alumina is shown to have a lower CTE than any of YAG, spinel, and 80% yttria / 20% zirconia. The sintered ceramic body fractures within the alumina substrate near the interface between the layers during annealing. Fracture will occur at the weakest area in the sintered body, and fracture occurring within the bulk alumina may indicate an interface strength that is approximately the same as or greater than the interface strength of the bulk alumina substrate. The location of the fracture (within the alumina) represents the extremely high interface strength (which may exceed the interface strength of the bulk first layer and the bulk second layer) achieved by using materials and methods as disclosed herein. The CTE difference between YAG and alumina is sufficient to cause fracture within the bulk sintered body while maintaining integrity at the interface between the two layers. Thin film deposition and / or thin film lamination methods used to form laminates typically exhibit much lower interface strength, and accordingly fracture and / or cracking occurs at the interface between the thin film layers (such as Figure 1 interlaminar fracture or delamination as depicted in the schematic diagram of FIG. Figure 3 As shown, YAG is most closely CTE-matched to alumina, and therefore it is expected that using a ceramic material having a coefficient of thermal expansion that varies by a greater amount relative to alumina for at least one first layer 100 (such as, for example, a combination of spinel as the first layer and an alumina substrate layer) will similarly produce a multilayer sintered body that is susceptible to fracture after sintering when alumina is used as the substrate material. Thus, the coefficient of thermal expansion (CTE) of alumina within the temperature range disclosed herein differs from the CTE of many corrosion-resistant materials by an amount sufficient to prevent the formation of an integral multilayer sintered body when alumina is used as the substrate material.

[0130] In addition to CTE matching, the multilayer sintered ceramic body preferably has high thermal conductivity for use as a component in a semiconductor plasma processing chamber. The zirconium oxide toughened alumina (ZTA) composition selected for use as the at least one second layer 102 (and at least a portion of the at least one third layer 103) will significantly affect the properties of the overall multilayer sintered body. The high thermal conductivity of the at least one second layer 102 is an important material property for effectively distributing heat and thereby avoiding local overheating within the at least one second layer during use (especially when used as a dielectric window component or an RF window component). Such local overheating can cause cracking or fracture of the overall multilayer sintered body. It is reported in the literature that zirconium oxide has a lower thermal conductivity than alumina, so the amount of zirconium oxide will affect the thermal conductivity of the at least one second layer 102. Although pure alumina is known to have high thermal conductivity, the CTE mismatch precludes its use in combination with the material for use as the at least one first layer 100 disclosed herein. While there may be no practical lower limit to the minimum amount of zirconia in the at least one second layer 102 for reasons of thermal conductivity, in order to provide CTE matching with the at least one first layer 100 and high thermal conductivity (approximately the same as the thermal conductivity of alumina), at least one second layer 102 comprising at least one of stabilized zirconia and partially stabilized zirconia in an amount of about 5 volume % and greater, up to and including 30 volume %, with the balance comprising about 70 volume % to 95 volume % of the second crystalline phase of alumina is preferred.

[0131] In order to provide at least one second layer 102 with sufficient thermal conductivity for use in, for example, high frequency applications (such as RF or dielectric window or cover components), at least one second layer 102 having up to and including about 30 volume % zirconium oxide, and in some embodiments preferably not greater than 25 volume % may be preferred. A second layer 102 having greater than 30 volume % zirconium oxide may not provide sufficient thermal conductivity for use as a component in a semiconductor plasma processing chamber requiring high thermal conductivity. Compositions of at least one second layer 102 having greater than 30 volume % zirconium oxide may produce high thermal gradients within the at least one second layer 102 and may result in fracture and / or cracking.

[0132] Figure 7 The results for the coefficient of thermal expansion from 200°C to 1400°C are shown for at least one second layer 102 having zirconium oxide present in an amount of 10% to 30% by volume as disclosed herein. The CTE value as a function of temperature for at least one second layer (not shown) comprising 5% by volume zirconium oxide is generally between the range for pure alumina and at least one second layer comprising 10% by volume zirconium oxide. Figure 8The at least two separate crystalline phases of zirconium oxide and aluminum oxide are shown, so the volume mixing rule known to those skilled in the art is used to calculate the CTE values ​​for 5 volume %, 25 volume % and 30 volume % zirconium oxide. The CTE is shown to increase with increasing amount of zirconium oxide by volume, as shown in FIG. Figure 7 As shown. Depending on the volume of zirconium oxide in the ZTA (zirconia toughened alumina) of the at least one second layer 102, the CTE of the at least one second layer may be greater than, substantially equal to, equal to, or less than (varying by amounts within the ranges disclosed herein) the CTE of the at least one first layer 100 (comprising YAG, spinel, or yttria and zirconia) comprising the monolithic multi-layer sintered ceramic body. Therefore, as used herein, the CTE difference generally refers to the absolute value of the CTE difference, unless otherwise specifically stated.

[0133] High toughness values ​​for the at least one second layer 102 are preferred for improved handling and prevention of fracture and / or cracking in the multilayer sintered ceramic body. To enhance the toughness of the at least one second layer 102 comprising alumina and zirconia, toughening and / or stabilization of the at least one second layer is preferred. Without wishing to be bound by any particular theory, the toughening and stabilization mechanisms disclosed herein may serve to stabilize the tetragonal phase of zirconia, thereby limiting its transformation (at lower temperatures) to the monoclinic phase, which is associated with a large volume change of approximately 4.5%, making the phase stability of the tetragonal zirconia preferred. Stabilization of the tetragonal zirconia may be achieved by any stabilization method known to those skilled in the art, but is not limited thereto.

[0134] The combination of zirconia and alumina in the at least one second layer can provide phase change toughening by dispersing tetragonal zirconia particles, at least a portion of which convert to a monoclinic crystalline form upon crack propagation. As known to those skilled in the art, the volume expansion from tetragonal zirconia to monoclinic zirconia provides phase change or dispersion toughening in the at least one second layer 102. In an embodiment, the at least one second layer 102 may comprise a composite of particles of crystalline phases of zirconium oxide and alumina (also referred to herein as composite oxide or ZTA, which stands for dispersion or phase change toughened ceramic) in the disclosed volumetric amounts. This toughening method can be affected by the powder particle size, shape, and location of the tetragonal and monoclinic, dispersed zirconia phases in the alumina medium.

[0135] Another stabilization method utilizes varying molar amounts of stabilizing compounds comprising yttrium oxide, calcium oxide, lanthanum oxide (La2O3), cerium oxide (CeO2), samarium oxide (Sm2O3), and magnesium oxide, and combinations thereof, to stabilize zirconium oxide, preferably in a tetragonal or cubic phase (the monoclinic phase of zirconium oxide is stable at room temperature; therefore, the tetragonal and cubic phases are considered metastable phases when present at room temperature). The relative amounts and types of these stabilizing compounds can result in at least one second layer 102 comprising zirconium oxide comprising at least one of fully stabilized zirconium oxide (SZ) and partially stabilized zirconium oxide (PSZ). Generally, the stabilizing compounds can be selected for their valence and atomic radius relative to zirconium (Zr). Those stabilizing compounds having a larger atomic radius than zirconium favor the stabilization of the tetragonal and / or cubic phases. In some embodiments, yttrium oxide may be selected as a tetragonal phase stabilizing compound having a lower valence (+3) and a larger atomic radius (180 pm) than zirconium oxide (having an atomic radius of 160 picometers (pm)). Generally, those stabilizing compounds having a lower valence (coordination number) than zirconium oxide are preferred. Without being bound by a particular theory, the use of those stabilizing compounds having a lower valence than zirconium oxide (+4) may result in the introduction of oxygen vacancies, which may increase dielectric losses at high frequencies (such as RF or microwave frequencies). Thus, in some embodiments, a stabilizing compound such as cerium oxide (CeO 2 ) having the same valence as zirconium oxide (+4) and a larger atomic radius (185 pm) may stabilize the tetragonal and / or cubic phases without introducing oxygen vacancies. In some embodiments, a combination of at least two of these stabilizing compounds may be preferred and may be combined in any combination in the amounts disclosed herein to stabilize the zirconium oxide comprising at least one second layer 102 and / or at least one third layer 103. Stabilizing compounds can be added to at least one of the second and / or third powder mixtures according to the disclosed methods. Table 1 lists stabilizing compounds that produce stabilized zirconia (SZ) and / or partially stabilized zirconia (PSZ) and their molar amounts and weight percentages. Stabilizing zirconia with the disclosed stabilizing compounds can alter the CTE of at least one third layer, and the amount of zirconia can be adjusted accordingly.

[0136] Table 1

[0137]

[0138] In an embodiment, the at least one second layer 102 may comprise particles or grains of zirconium oxide (PSZ, SZ, and combinations thereof) dispersed in a host medium of aluminum oxide, wherein the at least one second layer comprises a particle composite (composite oxide) having two separate crystalline phases of aluminum oxide and zirconium oxide. Preferably, the at least one second layer 102 does not form a solid solution. The formation of a solid solution may reduce thermal conductivity, and therefore the at least one second layer 102 comprises separate crystalline phases of zirconium oxide and aluminum oxide. Figure 8 The x-ray diffraction results depicted separate crystalline phases of zirconium oxide and aluminum oxide, confirming that the at least one second layer 102 comprises separate crystalline phases without forming a solid solution. X-ray diffraction was performed for all measurements disclosed herein using a PANanlytical Aeris XRD model capable of identifying crystalline phases to approximately + / - 5%. According to embodiments of the at least one second layer, the presence of Figure 8 The small amount of yttria in the X-ray diffraction pattern of may be caused by partial stabilization of zirconia (yttria partially stabilized zirconia, PYSZ).

[0139] In addition, the use of compounds known to form glass, such as magnesium oxide, silicon dioxide, and calcium oxide, as sintering aids in the at least one second layer 102 can produce a glassy phase with low thermal conductivity that exists between the grains, thereby adversely affecting thermal conductivity. Therefore, in some embodiments, it is preferred that the at least one second layer 102 contain magnesium oxide and / or calcium oxide in a range of about 2 ppm to 100 ppm, preferably about 2 ppm to 75 ppm, preferably about 2 ppm to 50 ppm, preferably about 2 ppm to 25 ppm, preferably about 2 ppm to 20 ppm, preferably about 2 ppm to 10 ppm, preferably about 8 ppm, preferably about 2 ppm, and less, relative to the mass of the at least one second layer, as measured using ICPMS. In another embodiment, the at least one second layer 102 may contain silicon dioxide in an amount of about 14 ppm to 100 ppm, preferably about 14 ppm to about 75 ppm, more preferably about 14 ppm to about 50 ppm, preferably about 14 ppm to about 30 ppm, preferably about 14 ppm and less (as measured using ICPMS) relative to the mass of the at least one second layer 102. The second layer 102 containing a sintering aid within the disclosed range can provide a multilayer sintered ceramic body that is free of or substantially free of a glass phase, thereby providing high thermal conductivity of the multilayer sintered ceramic body. Disclosed herein are multilayer sintered ceramic bodies comprising at least one second layer 102 that is free of or substantially free of dopants and / or sintering aids as disclosed herein.

[0140] Thermal conductivity (as the product of diffusivity, density, and known heat capacity) was calculated by performing thermal diffusivity measurements (at ambient temperature and at 200° C.) on at least one second layer 102 comprising approximately 16% by volume of yttria-partially stabilized zirconia (3 mol%) and the balance being alumina according to ASTM E1461-13. In an embodiment, the at least one second layer 102 comprising approximately 16% by volume of yttria-partially stabilized zirconia was calculated to have a thermal conductivity of approximately 25 W / mK at ambient temperature and a thermal conductivity of approximately 14 W / mK at 200° C. Thus, the at least one second layer 102 preferably comprises zirconia in an amount by volume of from about 5% to about 30%, preferably from about 5% to about 20%, preferably from about 10% to about 20%, and preferably from about 15% to about 20%, relative to the volume of the at least one second layer 102. The at least one second layer 102 having a composition within the ranges as disclosed herein provides thermal conductivity sufficient for use as, for example, dielectric windows, RF windows, lids, and other components requiring high thermal conductivity in plasma processing chambers as disclosed herein.

[0141] To prevent local hot spots and overheating during use, particularly for RF applications, low dielectric loss is preferred. For example, dielectric loss can be affected by material properties such as particle size and the presence of impurities, sintering aids, and / or dopants. The presence of impurities and / or sintering aids and / or dopants, such as silicon dioxide in particular, in the at least one second layer 102 can lead to higher dielectric loss. The use of a high-purity / low-impurity starting powder and methods for maintaining that purity result in at least one second layer 102 having a high overall purity and a correspondingly low overall impurity content. Thus, in embodiments, the at least one second layer 102 as disclosed can have a total impurity content of 5 ppm to 200 ppm, preferably 5 ppm to 150 ppm, preferably less than 100 ppm, preferably less than 50 ppm, preferably less than 25 ppm, preferably less than 15 ppm, preferably 10 ppm to 100 ppm, preferably 10 ppm to 80 ppm, preferably 10 ppm to 60 ppm, preferably 10 ppm to 40 ppm, preferably 20 ppm to 80 ppm, and preferably 30 ppm to 60 ppm, relative to the mass of the at least one second layer, as measured using ICPMS. In embodiments, the at least one second layer 102 is formed from a powder mixture comprising silicon dioxide in an amount of about 14 ppm to 100 ppm, preferably about 14 ppm to 75 ppm, preferably about 14 ppm to 50 ppm, preferably about 14 ppm to 25 ppm, preferably about 14 ppm, relative to the total mass of the calcined powder mixture. In an embodiment, the at least one second layer 102 may contain magnesium oxide (MgO) in an amount of about 2 ppm to 100 ppm, preferably about 2 ppm to 75 ppm, preferably about 2 ppm to 50 ppm, preferably about 2 ppm to 25 ppm, preferably about 2 ppm to 20 ppm, preferably about 2 ppm to 10 ppm, preferably about 8 ppm and less, and preferably about 2 ppm, relative to the mass of the at least one second layer 102, as measured using an ICPMS method.

[0142] For use in plasma processing chambers, particularly those operating in the RF range, a multilayer sintered ceramic body 98 having a low dielectric loss (tangent δ) is preferred. In embodiments, the at least one second layer 102 may have the largest thickness (and correspondingly the largest volume) of the multilayer sintered ceramic body 98, and thus the properties associated with the at least one second layer may significantly affect the electrical and other properties of the sintered body, such as thermal conductivity. The dielectric loss of the sintered body may be affected by the purity of the at least one second layer 102, particularly the silicon dioxide content. Thus, the at least one second layer 102 may contain magnesium oxide and / or calcium oxide in an amount of about 2 ppm to 100 ppm, preferably about 2 ppm to 75 ppm, preferably about 2 ppm to 50 ppm, preferably about 2 ppm to 25 ppm, preferably about 2 ppm to 20 ppm, preferably about 2 ppm to 10 ppm, and preferably about 2 ppm, each relative to the mass of the composite oxide second layer 102. In further embodiments, at least one second layer 102 as disclosed herein may be formed from at least one powder mixture having a Si content of about 14 ppm and greater, preferably 14 ppm to 100 ppm, preferably 14 ppm to 75 ppm, preferably 14 ppm to 50 ppm, preferably 14 ppm to 25 ppm, preferably 14 ppm to 20 ppm, preferably about 14 ppm, relative to the total mass of the second layer 102. In embodiments, the second layer may have a total impurity content of 5 ppm to 200 ppm, preferably 5 ppm to 150 ppm, preferably less than 100 ppm, preferably less than 50 ppm, preferably less than 25 ppm, preferably less than 15 ppm, preferably 10 ppm to 100 ppm, preferably 10 ppm to 80 ppm, preferably 10 ppm to 60 ppm, preferably 10 ppm to 40 ppm, preferably 20 ppm to 80 ppm, preferably 30 ppm to 60 ppm, relative to the total mass of the second layer.

[0143] The total impurity content of the at least one second layer 102 comprising calcia, silica, and magnesia in amounts as disclosed herein provides a total impurity content of less than 7×10 0- ... -4 In one embodiment, the at least one second layer 102 is free (0 ppm or at or below the detection limit) or substantially free (2 ppm to 5 ppm) of dopants and / or sintering aids as disclosed herein. The at least one second layer 102 as disclosed herein provides a multilayer sintered ceramic body or a component made therefrom having low dielectric loss and suitable for use as a chamber component, particularly as a window or cover component for use in a high frequency, RF plasma processing chamber.

[0144] Plasma processing chambers used to manufacture semiconductor devices are designed to accommodate substrates with ever-increasing diameters, which in turn requires larger chamber components. These chamber components manufactured from the multilayer sintered ceramic bodies disclosed herein can have a maximum dimension of, for example, 100 mm to about 625 mm, preferably 100 mm to 622 mm, preferably 200 mm to about 625 mm, preferably 300 mm to about 625 mm, preferably 400 mm to about 625 mm, preferably 500 mm to about 625 mm, preferably 300 mm to 622 mm, preferably 400 mm to 622 mm, and preferably 500 mm to 622 mm.

[0145] Many materials known to provide corrosion and erosion resistance are difficult to sinter, resulting in low density and corresponding low sintered strength, which can lead to fracture or cracking. This makes it challenging to manufacture large, monolithic, solid components from these corrosion-resistant materials. A high-strength material (which matches the CTE of the corrosion-resistant material as disclosed herein) is required to constitute the at least one second layer 102 to enable the manufacture of large-sized chamber components. The at least one second layer 102 provides mechanical strength and hardness to the monolithic, multi-layer, corrosion-resistant sintered body (and components manufactured therefrom) as disclosed herein. At least one second layer 102 can be sintered to a very high density, and in embodiments, to a fully dense body, which provides the mechanical strength and hardness necessary to manufacture large-scale multilayer sintered bodies, for example, having a maximum dimension of 100 mm to about 625 mm, preferably 100 mm to 622 mm, preferably 200 mm to about 625 mm, preferably 300 mm to about 625 mm, preferably 400 mm to about 625 mm, preferably 500 mm to about 625 mm, preferably 300 mm to 622 mm, preferably 400 mm to 622 mm, and preferably 500 mm to 622 mm. Density measurements were performed according to ASTM B962-17 for sintered bodies having 10% to 16% by volume of zirconium oxide (with the balance comprising alumina), and the density of at least one second layer having 5%, 20%, 25%, and 30% zirconium oxide was calculated using the volume mixing rule. A theoretical density of 99% was assumed in the calculated density. Table 2 lists the density of at least one second layer comprising zirconium oxide and aluminum oxide crystalline phases as disclosed herein.

[0146] Table 2

[0147] Volume% ZrO2 Volume%Al2O3 Average density (g / cc) %Theoretical Density % Volume Porosity 5 95 4.04 >99 <1 10 90 4.19 100 0 12 88 4.23 99.9 0.12 12 88 4.22 99.8 0.21 12 88 4.20 99.2 0.83 16 84 4.32 100 0 20 80 4.36 >99 <1 25 75 4.46 >99 <1 30 70 4.57 >99 <1

[0148] The theoretical density of zirconium oxide is reported to be 6.09 g / cc, while the theoretical density of aluminum oxide is reported to be 3.98 g / cc. The theoretical density of the at least one second layer 102 is calculated according to volume mixing rules known to those skilled in the art (using these density values ​​and the volume fractions of the respective crystalline phases of zirconium oxide and aluminum oxide). For the embodiments of the at least one second layer 102 as disclosed in Table 2, very high densities (99% to 100% of the theoretical density) were measured. As measured according to ASTM B962-17, the at least one second layer 102 disclosed herein, comprising zirconium oxide in an amount of about 16 volume % (and the balance being aluminum oxide), was measured to have a density of about 4.32 g / cc. These high densities provide sufficient mechanical strength and hardness (Young's modulus) to form a monolithic multilayer sintered body of large size (up to and including a maximum dimension of about 625 mm).

[0149] At least one second layer 102 as disclosed herein, comprising zirconium oxide in an amount of about 16 volume percent (and the balance alumina), was tested in a four-point flexural test to determine flexural strength according to ASTM Standard C 1161-3, “Standard Test Method for Flexural Strength of Advanced Ceramics at Ambient Temperature.” The four-point bend test is superior to the three-point bend test because it exposes a larger volume of the sample to a uniform maximum stress and, therefore, produces a strength that is more representative of the material being tested. The three-point bend test exposes a relatively smaller volume of the sample to the maximum stress, and, therefore, reported strength values ​​for the three-point flexural test tend to be higher. Therefore, comparisons between the three-point and four-point flexural tests present challenges due to significant variations in their measurement setups and methods. Using ASTM Standard C 1161-3, extremely high strength values ​​were achieved in a four-point bend configuration for the at least one second layer 102 comprising 16 volume percent zirconium oxide. Table 3 lists the flexural strength (modulus of rupture, MOR) and other material properties of at least one layer 102 comprising approximately 16% partially stabilized ZrO2 with the balance being alumina.

[0150] During use in a semiconductor reactor under vacuum conditions, corrosion-resistant multi-layer components made from the multi-layer sintered ceramic bodies as disclosed herein can withstand bending stresses exceeding 500 mm across the component dimensions. The properties of high strength and increased hardness / Young's modulus may be necessary for the application of materials used as components as disclosed herein in large-scale etching and / or deposition chambers. The flexural strength of 98% dense alumina is reported to be approximately 375 MPa, and the hardness (elastic modulus / Young's modulus) is reported to be approximately 350 GPa (Coorstek Advanced Alumina Data Sheet, available online). The at least one second layer 102 as disclosed herein can provide mechanical strength and hardness / Young's modulus that is approximately the same as or exceeds that of alumina while providing the desired CTE match with the at least one first layer 100 and the at least one third layer 103. The use of at least one second layer 102 as disclosed herein can significantly enhance the flexural strength and stiffness of integral multi-layer components fabricated from multi-layer sintered ceramic bodies, enabling the fabrication of large (>100 mm to about 625 mm and larger in size) components having high strength, high hardness, and resistance to halogen-based corrosion and erosion, such as are necessary for use as components in semiconductor plasma processing chambers.

[0151] At least one first layer 100 provides a chemically inert, plasma-facing surface 106 that is resistant to the corrosive effects of halogen process gases and the erosive effects of plasma ion bombardment (inert gases such as argon and other process gases known in the art can generally be used), while at least one second layer 102 provides mechanical strength to the multi-layer corrosion-resistant sintered body disclosed herein. At least one second layer 102 can be sintered to a very high density, and in embodiments, is sintered to a fully dense body, which provides the mechanical strength necessary to manufacture large-sized multi-layer sintered bodies, such as 100 mm to about 625 mm in diameter, preferably between 200 mm and 625 mm, preferably between 250 mm and about 625 mm, preferably between 300 mm and about 625 mm, more preferably between 350 mm and about 625 mm, more preferably between 400 mm and about 625 mm, more preferably between 450 mm and about 625 mm, more preferably between 500 mm and about 625 mm. Table 3 lists the properties of the at least one second layer 102 comprising 16 volume percent partially stabilized zirconia with the balance being alumina.

[0152] Table 3

[0153]

[0154] Now refer to Figure 6In an embodiment, a multilayer sintered ceramic body 98 is disclosed that includes at least one third layer 103. The at least one third layer 103 includes a polycrystalline phase having at least one of YAG, alumina, and zirconia. The zirconia may include at least one of unstabilized zirconia, partially stabilized zirconia, and stabilized zirconia.

[0155] In embodiments, the at least one third layer 103 comprises YAG, measured by area, relative to the area of ​​an exemplary polished surface of the at least one third layer, at least 50% to 90%, preferably at least 50% to 80%, preferably at least 50% to 60%, and more preferably at about 51% to 55%. Area measurements are performed using backscattered detection images from a SEM, which are imported into ImageJ software, after which the respective phases of YAG and alumina / zirconia are measured based on their surface area percentages within the entire exemplary image area. The at least one third layer 103 of the multilayer sintered ceramic body may constitute a unitary body and thus contain crystalline phases of at least YAG, zirconia, and alumina throughout, produced according to the processes disclosed herein. In other words, the structure measured on the surface represents the structure within the volume of the at least one third layer of the body. Thus, the at least one third layer of the multilayer sintered ceramic body may contain the same relative amounts of YAG, zirconia, and alumina crystalline phases on the surface and throughout the entire volume of the sintered body.

[0156] exist Figure 26 a) and Figure 26 The multiphase structure of the at least one third layer 103 is depicted in the 1000× SEM micrograph of b). Figure 26 a) shows the microstructure of at least one third layer 103 comprising large (maximum dimension of about 80 μm to about 200 μm) regions of YAG phase (white / light grey regions) and an alumina phase (black regions throughout) with zirconium oxide phase (smaller, about 10 μm diameter white regions within the alumina phase) dispersed therein. This can be achieved by Figure 26 a) Microstructure of: Powders of alumina, yttrium oxide, and at least one of unstabilized zirconia, partially stabilized zirconia, and stabilized zirconia are dry mixed for about 16 hours without using grinding / mixing media to form a third powder mixture according to embodiments as disclosed herein. The absence of grinding media and dry mixing conditions can promote the following: Figure 26 The microstructure depicted in a).

[0157] Figure 26b) shows the microstructure of at least one third layer 103 at 1000× and 5000× (insert), which comprises a finely dispersed (maximum size of about 5 μm to about 20 μm) YAG phase (white / light gray areas) and an alumina phase (black areas) with a zirconium oxide phase (small size, about 3 μm diameter white areas within the alumina phase) dispersed therein. It can be formed by the following Figure 26 b) Microstructure: A 40 wt% ethanol slurry of a powder comprising alumina, yttria, and at least one of unstabilized zirconia, partially stabilized zirconia, and stabilized zirconia is formed to form a third powder mixture according to embodiments as disclosed herein. Alumina media is added at about 100% loading relative to the weight of the powder, and the powder is tumble milled for 20 hours. The high media loading and extended milling time can facilitate Figure 26 b) shows a finely dispersed, highly uniform microstructure.

[0158] The at least one third layer 103 also provides improved machinability and CTE matching (within the ranges disclosed herein) to the at least one first layer 100 and the at least one second layer 102. Figure 22 a), light grey / white regions (containing YAG) and alumina / zirconia regions (depicted as dark grey or black with white regions therein) each form regions approximately 100 μm and larger in size, as shown in the SEM depicting the multiphase third layer 103. Multiple SEM images were analyzed using ImageJ to determine the area percentage of each phase making up the multiphase layer 103. Figure 26 As shown in the SEM image of a) (and other images taken at the same magnification of 500×), the multi-layer sintered body includes at least one third layer 103, comprising a YAG phase with an area ratio of approximately 51% to 63%, preferably approximately 51% to 60%, preferably approximately 55% to 60%, and preferably approximately 60%, based on an alumina-rich phase (containing YAG) with the balance consisting of alumina and zirconia (wherein the zirconia comprises at least one of unstabilized zirconia, partially stabilized zirconia, and stabilized zirconia). This multi-phase structure comprising regions containing YAG and regions containing alumina and zirconia can provide improved fracture toughness and crack growth resistance by deflecting cracks along the interface between these regions, thereby increasing crack length. Furthermore, the at least one third layer 103 can reduce the size and frequency of defects that may form during machining, thereby maintaining mechanical strength and toughness by absorbing the energy generated during machining within the multi-phase, at least one third layer 103.

[0159] In embodiments, the at least one third phase comprises a zirconia-toughened alumina (ZTA) phase comprising at least one of unstabilized zirconia, partially stabilized zirconia, or stabilized zirconia in an amount of about 16 volume percent with the balance being alumina.

[0160] In some embodiments (e.g. Figure 26 ), at least one third layer 103 comprises a YAG phase (white / light gray areas) in an amount greater than 50% to about 55% by area (and thus by volume), an alumina phase (black / gray) in an amount from about 45% to less than 50% and a zirconia phase (white areas within the black / gray) dispersed within the alumina phase, wherein the zirconia comprises about 16 volume percent 3 mol% yttria partially stabilized zirconia.

[0161] The at least one third layer 103 also provides improved uniformity during sintering by combining the yttria, zirconium oxide, and aluminum oxide powders to form a third powder mixture having similar sintering characteristics as the at least one first powder mixture. The third powder mixture can provide more uniform heat transfer within the powder mixture during sintering according to the methods disclosed herein, thereby providing more uniform sintering characteristics (such as sintering temperature and densification rate of the corresponding layers).

[0162] exist Figure 22 a) and Figure 22 b) depicts a second interface 105 between at least one third layer 103 and at least one second layer 102. As shown, the second interface 105 (described in greater detail herein) can provide enhanced toughness between the at least one third layer 103 and the at least one second layer 102. This improved toughness can be achieved through a number of factors, such as the multiphase nature of the second interface 105 (which can provide increased area between the phases to deflect crack propagation) and the interlocking effect provided by the morphology and nonlinearity of the multiple phases at the second interface 105. The mixing between the powder mixtures forming the at least one third layer 103 and the at least one second layer 102 provides the second interface 105, which, in some embodiments, may not have a clearly defined boundary between the third layer 103 and the second layer 102. The second interface 105 can, in some embodiments, comprise a diffusion boundary, and thus, properties such as composition, strength, fracture toughness, etc., can have gradients across the second interface 105. In other embodiments, the second interface 105 provides a different nonlinear boundary between the at least one second layer 102 and the at least one third layer 103. Various powder combining methods as disclosed herein for at least one third powder mixture can produce Figure 22b) at least one second interface 105 depicted in FIG. In an embodiment, the at least one second layer and the at least one third layer may be in contact, thereby forming the second interface 105, and thus the second and third layers are contiguous. In other embodiments, circuitry, heating elements, RF coils / antennas, etc. may be disposed between the second and third layers as required for a particular component application, and regardless of these features, the first and second layers may be contiguous or substantially contiguous.

[0163] In a preferred embodiment, the compositions of the at least one third layer 103, the at least one first layer 100, and the at least one second layer 102 are selected such that the absolute value of the difference in coefficient of thermal expansion (CTE) of the at least one first layer, the at least one second layer, and the at least one third layer, as measured in the temperature range of 25°C to 1700°C or in the temperature range of 200°C to 1400°C according to ASTM E228-17, is 0 to 0.75×10-6 / °C, preferably 0 to 0.7×10-6 / °C, preferably 0 to 0.6×10-6 / °C, preferably 0 to 0.5×10-6 / °C, preferably 0 to 0.45×10-6 / °C, preferably 0 to 0.4×10-6 / °C, preferably 0 to 0.6×10-6 / °C, preferably 0 to 0.5×10-6 / °C, preferably 0 to 0.45×10-6 / °C, preferably 0 to 0.6 ... The CTE matching between the at least one first layer 100, the at least one second layer 102, and the at least one third layer 103 can be provided in a temperature range from ambient temperature to about 1700° C. according to the methods disclosed herein. The selection of these materials that provide this CTE difference can reduce the interfacial stress at the nonlinear interface 104 and the second interface 105, thereby improving the adhesion between the layers of the multilayer sintered ceramic body and the components formed therefrom.

[0164] According to one embodiment, a monolithic multi-layer sintered ceramic body is disclosed herein, comprising at least one first layer 100 comprising at least one ceramic material comprising polycrystalline YAG; at least one second layer 102 comprising alumina and zirconia, wherein the zirconia comprises at least one of stabilized zirconia and partially stabilized zirconia; and at least one third layer 103 comprising a plurality of phases selected from at least one of the group consisting of YAG, alumina, and zirconia, wherein the zirconia comprises at least one of unstabilized zirconia, partially stabilized zirconia, and stabilized zirconia, wherein the ceramic body is preferably sintered at a temperature in the range of 25° C. to 1700° C. or in the range of 200° C. to 1400° C. according to ASTM D 1477. The absolute value of the difference in coefficient of thermal expansion (CTE) between at least one first layer, at least one second layer and at least one third layer measured by E228-17 is 0 to 0.75×10-6 / °C, preferably 0 to 0.7×10-6 / °C, preferably 0 to 0.6×10-6 / °C, preferably 0 to 0.5×10-6 / °C, preferably 0 to 0.45×10-6 / °C, preferably 0 to 0.4×10-6 / °C, preferably 0 to 0.35×10-6 / °C, preferably 0 to 0.3×10-6 / °C, preferably 0 to 0.25×10-6 / °C, preferably 0 to 0.2×10-6 / °C, preferably 0 to 0.15×10-6 / °C, preferably 0 to 0.1×10-6 / °C, preferably 0 to 0.08×10-6 / °C, preferably 0 to 0.04×10-6 / °C, and preferably 0 to 0.02×10-6 / °C, wherein the at least one first layer, the at least one second layer and the at least one third layer form an integral multilayer sintered ceramic body. These ranges of absolute values ​​of the CTE differences between the at least one first layer comprising polycrystalline YAG and the at least one second layer and the at least one third layer correspond to CTE differences of approximately 10% and less, preferably 9% and less, preferably 8% and less, preferably 6% and less, preferably 4% and less, preferably 3% and less, preferably 2.5% and less, preferably 2% and less, preferably 1.5% and less, preferably 1% and less, preferably 0.5% and less, and preferably 0.25% and less between any of the at least one first layer, the at least one second layer, and the at least one third layer as a percentage (as measured relative to the at least one first layer 100 comprising polycrystalline YAG).

[0165] In the temperature range from ambient temperature (or at least from 200° C. as depicted in the accompanying drawings) to about 1700° C. (or at least to 1400° C. as depicted in the accompanying drawings), the at least one first layer, the at least one second layer, and the at least one third layer are CTE matched within the disclosed range to form a monolithic multilayer sintered ceramic body. In an embodiment, the at least one first layer 100 may further comprise at least one crystalline phase selected from the group consisting of YAP (yttrium aluminum perovskite), YAM (yttrium aluminum monoclinic phase), yttrium oxide, aluminum oxide, and combinations thereof, the at least one crystalline phase being present in an amount of less than 5%, preferably less than 3%, and more preferably less than 1%, each by volume of the at least one first layer 100, as determined by x-ray diffraction, SEM imaging, and ImageJ analysis. Each crystalline phase of YAG, YAP, and YAM is preferably polycrystalline. Figure 9a ), Figure 9b )and Figure 9c ) shows CTE measurements of exemplary materials for forming at least one first layer and at least one second layer of a monolithic multi-layer sintered ceramic body according to embodiments over a temperature range from ambient temperature (or at least from 200° C. as depicted in the figures) to about 1700° C. (or at least to 1400° C. as depicted in the figures). All CTE measurements as disclosed herein were performed in accordance with ASTM E228-17 over a temperature range from 25° C. to 1700° C. or over a temperature range from 200° C. to 1400° C. The CTE measurements were performed on exemplary bulk materials. Figure 9a ) depicts a polycrystalline YAG first layer 100 (solid line) and a second layer (ZTA, dashed line) 102, the second layer comprising approximately 10 volume percent of at least one of stabilized zirconia and partially stabilized zirconia, with the remainder (90 volume percent) being alumina, relative to the total volume of the at least one second layer 102. Figure 9b ) depicts a polycrystalline YAG first layer 100 (solid line) and a second layer (ZTA, dashed line) 102, the second layer comprising approximately 20 volume % zirconium oxide and the balance (80 volume %) aluminum oxide, relative to the total volume of the at least one second layer. Figure 9c ) depicts at least one first layer 100 comprising polycrystalline YAG and at least one second layer 102 comprising approximately 16 volume percent zirconium oxide (with the balance being aluminum oxide) relative to the total volume of the at least one second layer.

[0166] In one embodiment, the composition range of the at least one second layer 102 (about 5% by volume to about 30% by volume zirconium oxide with the balance being aluminum oxide) can be suitable for CTE matching within a range of CTE matching and percentages with at least one first layer 100 comprising polycrystalline YAG. Thus, disclosed herein is a multilayer sintered ceramic body 98 comprising at least one second layer 102 and at least one first layer 100 comprising polycrystalline YAG, the at least one second layer comprising aluminum oxide and at least one of stabilized zirconium oxide and partially stabilized zirconium oxide in an amount of about 5% by volume to about 30% by volume, preferably about 10% by volume to about 30% by volume, preferably about 5% by volume to about 20% by volume, preferably about 10% by volume to about 20% by volume, relative to the volume of the at least one second layer. In a preferred embodiment, to more closely match the CTE of the polycrystalline at least one YAG first layer 100, the at least one second layer 102 may include at least one of partially stabilized zirconia and stabilized zirconia in an amount by volume of about 13% to about 19%, preferably about 14% to about 18%, preferably about 15% to about 17%, and more preferably about 16% by volume of each relative to the volume of the at least one second layer 102 (with the balance being alumina). These compositional ranges for the at least one second layer 102 are measured in accordance with ASTM E228-17 over a temperature range of about 0.4×10 -6 / ℃ and less, preferably 0.3×10 -6 / ℃ and less, preferably 0.25×10 -6 / ℃ and less, preferably about 0.2×10 -6 / ℃ and less, preferably 0.15×10 -6 / ℃ and less, preferably 0.1×10 -6 / °C and less, preferably 0.08×10-6 / °C and less, preferably 0.06×10-6 / °C and less, preferably 0.04×10-6 / °C and less, preferably 0.02×10-6 / °C and less, and preferably 0.01×10-6 / °C and less provide CTE matching with the YAG at least one first layer 100. As a percentage relative to the at least one first layer, the CTE difference (according to one embodiment, between any of the first, second, and third layers) may be 5% and less, preferably 4% and less, preferably 3% and less, preferably 2.5% and less, preferably 2% and less, preferably 1.5% and less, preferably 1% and less, preferably 0.5% and less, preferably 0.25% and less, and preferably 0.1% and less, for the at least one first layer, the at least one second layer, and the at least one third layer (as measured relative to the at least one first layer 100). According to the methods and stabilizing compounds disclosed herein, at least one second layer of zirconia may comprise at least one of stabilized zirconia and partially stabilized zirconia. A monolithic multi-layer sintered body having a maximum dimension of about 100 mm to about 625 mm has been formed, the monolithic multi-layer sintered body having at least one first layer 100 comprising polycrystalline YAG and at least one second layer 102 comprising approximately 16% by volume of partially stabilized zirconia.

[0167] In order to provide corrosion and erosion resistance suitable for use as a component in a plasma processing chamber, a polycrystalline, monolithic multilayer ceramic body having at least one first layer 100 comprising highly phase-pure polycrystalline YAG (>90 vol%) is preferred. However, the formation of substantially phase-pure YAG requires careful compositional and processing control in order to maintain stoichiometry and thereby form a sintered ceramic body comprising phase-pure YAG (composition of 37.5 + / - 0.1 mol % yttrium oxide and 62.5 + / - 0.1 mol % aluminum oxide). Other crystalline phases may typically be present, such as aluminum oxide, yttrium oxide, YAP, (YAlO3; yttrium aluminum perovskite phase) and YAM (Y4Al2O9; yttrium aluminum monoclinic phase) and combinations of these. As a guide, Figure 10 A yttrium oxide / aluminum oxide binary phase diagram is depicted. The horizontal axis corresponds to the mixture ratio of yttrium oxide and aluminum oxide in mole percent, while the vertical axis is the temperature in degrees Celsius. The left side of the horizontal axis corresponds to 100% aluminum oxide, while the right side corresponds to 100% yttrium oxide. Figure 10 The phase diagram shows the regions where the yttrium aluminum oxide phases of YAG, YAP, and YAM form and the conditions of molar composition and temperature necessary to produce these forms.

[0168] The crystalline phase and image-based porosity of at least one first layer 100 comprising YAG of a multilayer ceramic sintered body according to embodiments disclosed herein were measured using a combination of x-ray diffraction (XRD), SEM imaging, and image processing software (ImageJ). XRD was performed using a PANanlytical Aeris XRD model capable of identifying crystalline phases up to approximately + / - 5 volume %. Figure 13 X-ray diffraction results are depicted, confirming the formation of highly phase-pure polycrystalline YAG constituting at least one first layer 100. No other phases were identified within the detection limits of XRD. According to the known phase diagram, YAG exists as a linear compound, so the formation of phase-pure YAG presents a challenge and requires careful composition and process control. Such phase-pure YAG is disclosed in International Patent Application No. PCT / US20 / 60918, filed on November 17, 2020, which is incorporated herein by reference. At least one first layer 100 of YAG according to one embodiment may, in some embodiments, contain an excess of aluminum oxide and / or an excess of yttrium oxide, and may be substantially free of or free of dopants and / or substantially free of or free of sintering aids as disclosed herein. In other embodiments, the first layer comprising YAG may contain sintering aids and / or dopants in amounts as disclosed herein. In an embodiment, the polycrystalline YAG first layer 100 is substantially free of or free of dopants and may contain sintering aids in amounts as disclosed herein. The XRD of at least one first layer 100 of the multilayer ceramic sintered body disclosed herein may measure up to and including about 95% by volume phase purity. Figure 13 In the embodiment depicted by the XRD results, at least one first layer 100 of the monolithic multi-layer sintered ceramic body comprises at least about 95 volume % of the YAG phase.

[0169] To more accurately determine the phase purity, for example, up to and including about 99.8% by volume, SEM images are taken using a backscattered detection (BSD) method known to those skilled in the art. Using BSD, the YAG phase appears gray, the aluminum oxide phase appears black, the yttrium oxide phase appears white, and the porous portion (if present) also appears black. For polycrystalline YAG sintered ceramic bodies according to embodiments as disclosed herein, images are taken using the BSD method at 5000× to identify the YAG, aluminum oxide, and yttrium oxide phases, as well as any porous portions present, such as Figure 11 as described in a).

[0170] In order to distinguish the black area containing aluminum oxide from the black area containing porous parts, the BSD image was thresholded to black and white when using ImageJ processing software to highlight the black area that may contain porous parts or aluminum oxide in the BSD image, such as Figure 11b) for the same area. ImageJ, developed by the National Institutes of Health (NIH), is a Java-based public domain image processing and analysis program used for image processing of scientific multidimensional images. The BSD detector used for the measurements disclosed herein also has the ability to measure topographic features, thereby highlighting any deviations in the surface topography, such as porous portions of the surface. Using the topographic mode of the BSD detector, such as Figure 11 A topographic image was taken at 5000× across the surface of the same region of the polycrystalline YAG sintered ceramic body according to Example 7 as depicted in a), and Figure 12 The topographic image is shown in a). After thresholding the topographic image in ImageJ, Figure 12 The area containing the porous part of the surface is highlighted in b). Figure 12 a) The area containing aluminum oxide and / or porous parts is subtracted from the BSD image Figure 12 b) contains the area of ​​the surface porous portion, resulting in the area % of the alumina phase in the polycrystalline YAG sintered ceramic body according to the embodiments disclosed herein, thereby obtaining the volume %. At least one first layer 100 of the multilayer sintered ceramic body 98 disclosed herein may have porous portions and / or alumina phases on the surface and throughout the body. Therefore, in an embodiment, the multilayer sintered ceramic body may include a unitary body that includes YAG made according to the process disclosed herein and also includes alumina phases and porous portions distributed throughout the body. In other words, the structure measured on the surface (e.g., the plasma-facing surface 106) represents the structure within the volume of the bulk multilayer sintered ceramic body that includes YAG and, in an embodiment, also includes alumina. The combination of these analytical tools of multiple SEM imaging modes and ImageJ analysis can provide a determination of phase purity with a confidence level of approximately + / - 0.1 volume %. Using the disclosed method, the polycrystalline YAG sintered ceramic body according to Example 7 was measured to include about 0.1 volume % to about 0.2 volume % of an aluminum oxide phase, about 0.1 volume % to about 0.2 volume % of a porous portion, and about 99.6 volume % to about 99.8 volume % of a YAG phase. Taking into account measurement differences, the polycrystalline YAG sintered ceramic body may include the YAG phase in an amount of 99.4 volume % to 99.8 volume %, and may also include a porous portion in an amount of 0.1 volume % to 0.3 volume % and aluminum oxide in an amount of 0.1 volume % to about 0.3 volume %.

[0171] Thus, a multi-layer sintered ceramic body having at least one first layer 100 can be formed using the materials and methods disclosed herein, wherein the at least one first layer 100 comprises a YAG phase in an amount of 90% to 99.9% by volume, preferably 90% to 99.8% by volume, preferably 90% to 99.7% by volume, preferably 90% to 99.6% by volume, preferably 93% to 99.8% by volume, preferably 93% to 99.7% by volume, and preferably 93% to 99.6% by volume, each based on the volume of the at least one first layer 100.

[0172] To evaluate the grain size of the at least one first layer 100 comprising polycrystalline YAG, linear intercept grain size measurements were performed according to the Heyn linear intercept procedure described in ASTM Standard E112-2010 "Standard Test Method for Determining Average Grain Size". Grain size measurements were performed on an exemplary plasma-facing surface 106 (as listed in Table 4), and an average grain size of 1.1 μm to 6.3 μm was measured over 25 repetitions. Maximum and minimum grain sizes of 2 μm to 7.7 μm were also measured on an exemplary plasma-facing surface 106 of the at least one first layer 100 comprising YAG. The monolithic multilayer sintered ceramic body may have a plasma-facing surface 106 with a grain size, for example, of about 8 μm and less, preferably a maximum grain size of 6 μm and less. In some embodiments, the monolithic multilayer sintered ceramic body may have a plasma-facing surface 106 having an average grain size of 0.4 μm to 6.5 μm, preferably 0.4 μm to 5 μm, preferably 0.4 μm to 3 μm, preferably 0.8 μm to 6.5 μm, preferably 0.8 μm to 5 μm, preferably 0.8 μm to 3 μm, preferably 1 μm to 7 μm, preferably 1 μm to 6.5 μm.

[0173] Table 4

[0174]

[0175] To meet the corrosion and erosion resistance requirements for use as a component in a semiconductor processing chamber, a multilayer sintered ceramic body comprising at least one first layer 100 is preferably one having low porosity on the plasma-facing surface 106 and / or within the layer 100. Porous portions can serve as sites for the initiation of corrosion and erosion, and therefore, it is preferred that there be virtually no porous portions, pores, or voids within the at least one first layer 100 and / or on the plasma-facing surface 106 of the first layer 100 of the multilayer sintered body. The at least one first layer disclosed herein can have very small pores on the surface and throughout. Preferably, the at least one first layer 100 prepared according to the methods disclosed herein and comprising at least one crystalline phase of a ceramic material selected from the group consisting of YAG, magnesium aluminate spinel, and yttrium oxide and zirconium oxide is thus a unitary layer having uniformly distributed porosity throughout. In other words, the pores, voids, or porosity measured on the plasma-facing surface 106 can be representative of the pores, voids, or porosity within the bulk of the at least one first layer 100.

[0176] The porosity level on the sample surface was measured using SEM images acquired at 5000x magnification using a Phenom XL scanning electron microscope. The images were analyzed using ImageJ software. ImageJ, developed by the National Institutes of Health (NIH), is a Java-based, public domain image processing and analysis program used for image processing of scientific multidimensional images.

[0177] The pore size and the total area containing the porous portion were measured on seven SEM images using ImageJ software methods as disclosed herein. Images were taken at 5000× and each image had a total area of ​​approximately 53.7 μm × 53.7 μm, corresponding to approximately 2885 μm 2 Measure area of ​​a single image.

[0178] Figure 14 The porosity results measured on an exemplary plasma-facing surface 106 of at least one first layer 100 comprising YAG are shown, with total pore area (μm) plotted on the vertical axis. 2 ), and the horizontal axis represents the pore size in micrometers. The measurement was performed on 7 images taken at 5000×, each with an area of ​​53.7 μm × 53.7 μm, for a total measurement area of ​​approximately 2885 μm 2 The total area including the porous portion in any of the 7 images was measured to be approximately 0.015 μm 2 to about 0.3 μm 2 , preferably about 0.015 μm 2 to about 0.2 μm 2 , and preferably about 0.015 μm 2 to about 0.15 μm2 The maximum pore size on the plasma-facing surface 106 of the at least one first layer 100 comprising YAG was measured to be 0.7 μm and less, and the maximum area comprising the porous portion was found to be about 0.3 μm. 2 No pores with a pore size greater than 0.7 μm were measured in the seven images analyzed within the plasma-facing surface 106 of the at least one first layer 100 of polycrystalline YAG.

[0179] Figure 15 Depicted are included in mm 2 The area measured in μm 2 The cumulative fractional area of ​​the porosity (cumulative pore area) is expressed as Figure 14 Cumulative pore area (in μm) of a given pore size for the seven images referenced in 2 / mm 2 Using SEM images and ImageJ image processing methods as disclosed herein, the porosity (in μm) within each image was measured. 2 ) and across the total image area measured in mm 2 The at least one first layer 100 comprising YAG as disclosed herein comprises about 2 μm 2 / mm 2 to about 800 μm 2 / mm 2 , preferably about 2 μm 2 / mm 2 to about 600 μm 2 / mm 2 , preferably about 2 μm 2 / mm 2 to about 400 μm 2 / mm 2 , preferably about 2 μm 2 / mm 2 to about 300 μm 2 / mm 2The cumulative pore area, as measured using the SEM and image processing methods disclosed herein, was 0.6 μm. No pores with a pore size greater than 0.6 μm were measured in the seven images analyzed within the plasma-facing surface 106 of the at least one first layer 100 of the YAG multilayer sintered ceramic body. Thus, in the seven images, each having an area of ​​approximately 54 μm x 54 μm, the multilayer sintered ceramic body disclosed herein has at least one first layer 100 having a plasma-facing surface 106 containing an extremely low (<0.1% by area) area percentage porosity corresponding to pore sizes less than 1 μm, thereby providing a corrosion- and erosion-resistant plasma-facing surface 106 of the multilayer sintered ceramic body for use in a plasma processing chamber.

[0180] Figure 16 a) shows a 5000× SEM image showing the high-density sintered microstructure after a thermal etching process of the plasma-facing surface 106 of at least one first layer 100 comprising a polycrystalline YAG phase. Very fine-scale porosity with few pores is depicted on the plasma-facing surface 106 of the at least one first layer 100 of YAG. A nearly completely dense microstructure is depicted, with minimal porosity and pore sizes of approximately 1 μm and smaller visible. A multilayer sintered ceramic body according to one embodiment comprises at least one first layer 100 comprising polycrystalline YAG, the at least one first layer having a plasma-facing surface 106 comprising pores, wherein the pores have pore sizes of approximately 5 μm and smaller, down to submicron pore sizes of about 0.1 μm to about 5 μm, preferably about 0.1 μm to about 4 μm, preferably about 0.1 μm to about 3 μm, preferably about 0.1 μm to about 2 μm, and preferably about 0.1 μm to about 1 μm. In this embodiment, the at least one first layer 100 comprising YAG of the multi-layer sintered ceramic body 98 formed from the materials and processes described may comprise pores having a maximum dimension of 0.1 μm to 5 μm, preferably 0.1 μm to 4 μm, preferably 0.1 μm to 3 μm, preferably 0.1 μm to 2 μm, and 0.1 μm to 1 μm, as measured using the SEM and image processing methods disclosed herein. Approximately 22 pores were counted on a 54 μm x 54 μm plasma-facing surface 106.

[0181] Figure 16 b) For Figure 15 For each of the seven SEM images measured, the sum of the total surface area containing pores or porosity (in % of surface area) is depicted on the vertical axis, and the horizontal axis represents the corresponding pore size for a given % pore area in microns. Within a given image, the total area containing porosity and the total image measurement area are used to calculate the % pore area. Figure 16As depicted, the measurements in the seven SEM images correspond to at least one first layer 100 having a plasma-facing surface 106 comprising YAG, the plasma-facing surface comprising, as a percentage of the total area, an amount of 0.0005% to 2%, preferably 0.0005% to 1%, preferably 0.0005% to 0.5%, preferably 0.0005% to 0.05%, as measured from the SEM images and using ImageJ software and methods as disclosed herein. %, preferably 0.0005% to 0.03%, preferably 0.0005% to 0.005%, preferably 0.0005% to 0.003%, preferably 0.0005% to 0.001%, preferably 0.005% to 2%, preferably 0.05% to 2%, preferably 0.5% to 2%, preferably 0.005% to 2%, preferably 0.005% to 1%, preferably 0.05% to 2%, preferably 0.05% to 1%, and preferably 0.5% to 2%. Thus, in an image having an area of ​​approximately 54 μm×54 μm, the multilayer sintered ceramic body as disclosed herein includes a plasma-facing surface 106 that contains a very low (<1% by total area) percentage of porosity, thereby providing a corrosion- and erosion-resistant surface for the multilayer sintered ceramic body 98 for a plasma processing chamber.

[0182] The small maximum pore / void size and minimal porosity % area of ​​the at least one first layer 100 of the multilayer sintered body can achieve particle generation and corrosion and erosion reduction as required for use in semiconductor reactors. This minimal porosity corresponds to a high density, which also provides corrosion and erosion resistance, enabling their use as components in semiconductor etching and deposition applications.

[0183] Due to the difference in density of the layers, density measurement of multilayer bodies has proven to be challenging. Density measurements were performed on multilayer sintered ceramic bodies (as disclosed in Example 4) by dividing a sample cut from the full thickness of the multilayer sintered body into its first and second layers and measuring the density of these layers individually. Measurements were made according to the Archimedean impregnation method of ASTM B962-17, and a density of 4.55 g / cc to 4.57 g / cc, preferably about 4.56 g / cc, was measured for at least one first layer 100 of polycrystalline YAG. The reported density value is the average of 5 measurements, and the standard deviation of the measurements (using a known standard) was about 0.002. The density of a commercially available bulk YAG single crystal sample was measured using the method disclosed herein. An Archimedean density of 4.56 g / cc was obtained in 5 measurements, and this value was taken as the theoretical density of YAG as used herein. Thus, the theoretical density of the at least one first layer 100 comprising YAG of the monolithic multi-layer sintered ceramic body according to one embodiment is 98.5% to 100%, preferably 99% to 100%, preferably 99.5% to 100%, preferably 99.7% to 100%, and preferably approximately 100% of the theoretical density of YAG. The density of the at least one second layer 102 comprising approximately 16% by volume of at least one of stabilized zirconia and partially stabilized zirconia (with the balance being alumina) was measured according to the Archimedean impregnation method of ASTM B962-17 and calculated to be approximately 4.32 g / cc. The theoretical density of the at least one second layer comprising alumina and approximately 16% by volume of at least one of stabilized zirconia and partially stabilized zirconia was calculated using the volume mixing rule known in the art and was determined to be 4.31 g / cc to 4.33 g / cc, preferably approximately 4.32 g / cc, and was taken as the theoretical density of the at least one second layer 102. Thus, the at least one second layer 102 of the multi-layer sintered ceramic body (comprising approximately 16 volume % zirconium oxide and the balance aluminum oxide) has a percent theoretical density of 98% to 100%, preferably 99% to 100%, preferably 99.5% to 100%, and preferably approximately 100%. The monolithic multi-layer sintered ceramic body disclosed in accordance with this embodiment has at least one first layer and at least one second layer, each having a percent theoretical density (also expressed as relative density, RD) greater than 98%, preferably 98% to 100%, preferably 99% to 100%, preferably 99.5% to 100%, and preferably approximately 100% of the theoretical density of the monolithic multi-layer sintered ceramic body.

[0184] The relative density (RD) of a given material is defined as the ratio of the measured density of the sample to the theoretical density of the same material, as shown in the following formula. The volume porosity (Vp) is calculated from the density measurement as follows:

[0185]

[0186] Wherein p sample is the (Archimedean) density measured according to ASTM B962-17, r theory is the theoretical density as disclosed herein, and RD is the relative fractional density. Using this calculation, the volume porosity (Vp) level, as a percentage, is calculated from the measured density values ​​of each of the at least one first layer comprising YAG and the at least one second layer comprising alumina and approximately 16% by volume of partially stabilized zirconia of the multilayer ceramic sintered body according to Example 4 and embodiments as disclosed herein to be 0.04% to 2%, preferably 0.04% to 1%, preferably 0.04% to 0.8%, preferably 0.04% to 0.6%, preferably 0.04% to 0.5%, and preferably 0.04% to 0.4%.

[0187] The extremely high density of the at least one first layer comprising polycrystalline YAG (see, for example, Example 4) enables polishing of the at least one plasma-facing surface 106 to extremely low surface roughness Sa and low peak-to-valley Sz. Polishing was performed using methods known to those skilled in the art, and the plasma-facing surface 106 of the at least one first layer comprising polycrystalline YAG was measured to have an average surface roughness Sa of 8 nm and an average peak-to-valley Sz of 0.14 μm using a measurement method according to ISO Standard 25178-2-2012 as disclosed herein. The measurements were averaged over 10 repetitions. The plasma-facing surface 106 of the at least one first layer comprising polycrystalline YAG was measured to have a maximum surface roughness Sa of 10 nm and a maximum peak-to-valley Sz of 0.21 μm. The plasma-facing surface 106 of the at least one first layer comprising polycrystalline YAG was measured to have a minimum surface roughness Sa of 5 nm and a minimum peak-to-valley Sz of 0.057 μm. The disclosed surface features comprising the highly dense at least one first layer of YAG provide enhanced resistance to corrosion and erosion, thereby providing reduced particle generation during use as a component in a semiconductor plasma processing chamber.

[0188] Laminates as are common in the art (including, for example, cast and spray-dried layers) typically have laminates or layers exposed to plasma processing that have a lower density than that disclosed herein and, therefore, may not be polished to the very low surface roughness disclosed herein. Consequently, these laminates or layers may not provide adequate resistance to the corrosive and erosive effects of the harsh plasmas used during semiconductor processing, resulting in the release of particles into the plasma chamber during use.

[0189] The high density of at least one first layer of polycrystalline YAG can achieve high hardness values ​​for the plasma-facing surface 106 of the at least one first layer, which can provide resistance to the corrosive effects of ion bombardment used during typical plasma processes. Erosion or spalling can be caused by ion bombardment of the surface of the component or layer using an inert plasma gas such as Ar. Those materials with high hardness values ​​can be preferably used as materials for the component because their increased hardness values ​​provide greater resistance to ion bombardment and, thereby, greater resistance to erosion. Therefore, Vickers hardness measurements were performed on an exemplary plasma-facing surface 106 of at least one first layer 100 comprising polycrystalline YAG in accordance with ASTM Standard C1327 "Standard Test Method for Vickers Indentation Hardness of Advanced Ceramics". The testing equipment used for all hardness measurements was a Wilson Microhardness Tester Model VH1202. For the plasma-facing surface 106 of at least one first layer 100 of the multi-layer sintered ceramic body 98 as disclosed herein, a hardness value of at least 1200 HV, preferably at least 1400 HV, preferably at least 1800 HV, preferably at least 2000 HV, 1300 HV to 1600 HV, 1300 HV to 1500 HV, 1300 HV to 1450 HV, 1300 HV to 1400 HV, 1400 HV to 1600 HV, 1450 HV to 1600 HV, 1450 HV to 1550 HV was measured. The measured values ​​obtained using the Vickers hardness method known in the art are converted to SI units of GPa. The hardness values ​​measured were 12.75 GPa to 15.69 GPa, 12.75 GPa to 14.71 GPa, 12.75 GPa to 14.22 GPa, 12.75 GPa to 13.73 GPa, 13.73 GPa to 15.69 GPa, 14.22 GPa to 15.69 GPa, and preferably 14.22 GPa to 15.20 GPa. These high hardness values ​​can help to enhance resistance to ion bombardment during semiconductor etching processes and reduce corrosion during use, thereby providing extended component life when the multilayer sintered ceramic body is machined into multilayer sintered ceramic components with fine-scale features. Table 5 lists the hardness values ​​of the multilayer ceramic sintered bodies disclosed herein. The average values ​​are reported over eight test replicates using a 2 kgf load cell / applied load for Samples A, C, and B and a 0.025 kgf load for Sample D.

[0190] Table 5

[0191] sample Average value (GPa) Standard Deviation Maximum value (GPa) Minimum value (GPa) A 13.47 0.69 14.7 12.4 B 14.14 0.58 15.0 13.2 C 14.5 0.4 16.1 14.5 D 14.8 1.0 16.0 12.7

[0192] In one embodiment, the sintered ceramic bodies disclosed herein have an average hardness of 13.0 GPa to 16.0 GPa, calculated from eight test replicates using an applied load of 0.2 kgf, as measured according to ASTM Standard C1327. In another embodiment, the sintered ceramic bodies disclosed herein have an average hardness of about 13.5 GPa to 15 GPa, calculated from eight test replicates using an applied load of 0.2 kgf, as measured according to ASTM Standard C1327. In other embodiments, the sintered ceramic bodies have an average hardness of about 13.8 GPa to 15.8 GPa, calculated from eight test replicates using an applied load of 0.025 kgf.

[0193] The surface roughness of the plasma-facing surface 106 of at least one first layer can affect performance in a semiconductor processing chamber. Surface roughness measurements were performed under the environmental conditions of a Class 1 clean room using a Keyence 3D laser scanning confocal digital microscope model VK-X250X. The microscope was located on a TMC desktop CSP passive tabletop isolator with a natural frequency of 2.8 Hz. This non-contact system uses laser beam light and an optical sensor to analyze the surface by reflected light intensity. The surface roughness parameters Sa, Sdr, and Sz are well known in the field of basic technology and are described, for example, in ISO standard 25178-2-2012. Section 4.17 of the ISO standard describes surface roughness Sa, Section 4.1.6 describes Sz, and Section 4.3.2 describes Sdr. ISO 25178 Surface Texture (Area Roughness Measurement) is a collection of international standards related to surface roughness analysis compatible with this microscope. Sa represents the average roughness value calculated over a user-defined area (arithmetic mean height of the scale-limited surface) on the surface of a multilayer sintered ceramic body. Sz represents the maximum peak-to-valley distance (maximum peak-to-valley height of the scale-limited surface) across a user-defined region of the surface of the multilayer sintered ceramic body. Sdr is a calculated value defined as the "expanded interfacial area ratio" and is an expression of the ratio of the actual surface area increase over the surface area of ​​a completely flat surface. Sdr for a flat surface is assigned a value of zero, and this value increases with the slope of the surface. Larger values ​​correspond to greater increases in surface area. This allows for numerical comparisons of the degree of surface area increase across samples. Compared to a flat area, this value represents the additional surface area created by texture or surface features.

[0194] The sample surface was laser scanned using a confocal microscope at 50X magnification to capture detailed images of the sample. The parameters Sa (arithmetic mean height), Sz (maximum height), Ra (line roughness) and Sdr (developed interface area) were measured on selected areas of the polished surface (plasma-facing surface 106) of at least one layer 100 of the multilayer sintered ceramic body. These parameters were obtained on the profiles of 7 partitioned blocks. According to ISO specification 4288: Geometrical Product Specifications (GPS) - Surface texture: Profile method - Rules and procedures for evaluating surface texture, λchi (λ), which represents the measurement sampling length or area, was adjusted so that the line readings were limited to measurements from 5 of the 7 middle blocks. Surface areas were selected within the polished surface of the sample for measurement. Areas that best represent the typical sample surface were selected and used to calculate Ra, Sdr, Sa and Sz.

[0195] In one embodiment in which the plasma-facing surface 106 of at least one first layer comprises YAG, surface roughness measurements are performed according to ISO standard 25178-2-2012 and the Sa value on the surface is measured to be 0.0005 μm to 2 μm, preferably 0.0005 μm to 1.5 μm, preferably 0.0005 μm to 1 μm, preferably 0.0005 μm to 0.75 μm, preferably 0.0005 μm to 0.5 μm, preferably 0.0005 μm to 0.25 μm, preferably 0.000 0.010 μm, preferably 0.001 μm to 0.030 μm, preferably 0.001 μm to 0.020 μm and preferably 0.001 μm to 0.010 μm. Table 6 below lists the Sa, Sz, and Sdr values ​​of at least one first layer 100 according to embodiments disclosed herein, the at least one first layer including a plasma-facing surface 106 comprising YAG.

[0196] Table 6

[0197]

[0198] Thus, the at least one first layer 100 comprising YAG of the multi-layer sintered ceramic body according to the disclosed embodiments (and listed in Table 6) can have a plasma-facing surface 106 having a surface roughness Sa of 0.0005 μm to 2 μm, preferably 0.0005 μm to 1.5 μm, preferably 0.0005 μm to 1 μm, preferably 0.0005 μm to 0.75 μm, preferably 0.0005 μm to 0. ...5 μm, preferably 0.0005 μm to 0.75 μm, preferably 0.0005 μm to 0.5 μm, preferably 0.0005 μm to 0.75 μm, preferably 0.0005 μm to 0.5 μm, preferably 0.0005 μm to 0.5 μm, preferably 0.0005 μm to 0.5 μm, preferably 0.0005 μm to 0.5 μm, preferably 0.0005 μm to 0.5 μm, preferably 0.0005 μm to 0.5 μm, preferably 0.0005 μm to 0.5 μm, as measured according to ISO standard 25178-2-2012 to 0.25 μm, preferably 0.0005 μm to 0.125 μm, preferably 0.0005 μm to 0.075 μm, preferably 0.0005 μm to 0.050 μm, preferably 0.0005 μm to 0.025 μm, preferably 0.0005 μm to 0.020 μm, preferably 0.0005 μm to 0.015 μm, preferably 0.0005 μm to 0.010 μm, preferably 0.001 μm to 0.030 μm, preferably 0.001 μm to 0.020 μm and preferably 0.001 μm to 0.010 μm.

[0199] According to Table 6, the at least one first layer 100 containing YAG of the multi-layer sintered ceramic body according to embodiments disclosed herein may have a plasma-facing surface 106 having a peak-to-valley Sz of 0.3 μm to 5 μm, preferably 0.3 μm to 4 μm, preferably 0.3 μm to 3 μm, preferably 0.3 μm to 2 μm, preferably 0.3 μm to 1 μm, preferably 0.65 μm to 5 μm, preferably 1 μm to 5 μm, preferably 2 μm to 5 μm, preferably 0.35 μm to 3 μm and preferably 0.5 μm to 1 μm, as measured according to ISO standard 25178-2-2012.

[0200] According to Table 6, at least one first layer 100 comprising YAG of a multilayer sintered ceramic body according to embodiments disclosed herein may have a plasma-facing surface 106 having a developed interfacial area Sdr of 5×10 -5 Up to 550×10 -5 , preferably 30×10 -5 Up to 400×10 -5 , preferably 30×10 -5 to 200×10 -5 And preferably 40×10 -5 to 100×10 -5 .

[0201] To evaluate performance in halogen-based plasma applications, etching was performed as follows on a sintered ceramic body prepared according to one embodiment and including at least one first layer 100 comprising YAG.

[0202] To evaluate etching performance, polished ceramic samples with a plasma-facing surface containing a first layer of YAG measuring 6 mm × 6 mm × 2 mm were mounted onto a c-plane sapphire wafer using a silicone-based heat-dissipating compound. Areas of each part exposed to the etching process were blocked by bonding a 5 mm × 5 mm square of sapphire ceramic to the sample surface.

[0203] The dry etching process is carried out using industry standard equipment Plasma-Therm Versaline DESC PDC deep silicon etcher. Etching is completed using a 2-step process with a total duration of 6 hours. Etching method is carried out under a pressure of 10 mtorr, a bias voltage of 600 volts and an ICP power of 2000 watts. Etching method is divided into a first etching step under the argon flow rate of 90 standard cubic centimeters per minute (sccm) CF4 flow rate, 30 standard cubic centimeters per minute (sccm) oxygen flow rate, 20 standard cubic centimeters per minute (sccm) and a second etching step under the argon flow rate of 100 standard cubic centimeters per minute (sccm), wherein the first etching step and the second etching step are each carried out for 300 seconds and repeated for a combined duration of 6 hours. The etching conditions for evaluating sample performance are selected here to subject disclosed materials to extreme etching conditions in order to differentiate performance. After the etching procedure is completed, surface roughness parameters Sa, Sz and Sdr are measured using a method as disclosed herein. Table 7 lists the results after etching (using the 2-step process as disclosed herein) on various samples having a plasma-facing surface 106 of at least one first layer 100 comprising YAG.

[0204] Table 7

[0205]

[0206] Exemplary plasma-facing surfaces 106 of at least one first layer 100 comprising YAG were prepared with excess alumina (samples 311 and 322), zirconium oxide doping (sample 298), stoichiometric YAG (samples 454 and 223), and reduced relative density (RD) (sample 454-1). As listed in Table 7, the process conditions (Process) are listed as temperature T (° C.), pressure P (MPa), and time t (min) used to prepare each of the various samples according to the methods disclosed herein. Where applicable, annealing was performed in air at 1400° C. for 8 hours.

[0207] In one embodiment, the present disclosure relates to a multilayer sintered ceramic body and / or a component made therefrom, the multilayer sintered ceramic body having at least one first layer 100 comprising YAG, the at least one first layer having a plasma-facing surface 106 that provides, in unetched areas prior to an etching or deposition process, a surface roughness according to ISO standard 25178-2-2012, section 4.1.7, of less than 15 nm, more preferably less than 13 nm, more preferably less than 10 nm, more preferably less than 8 nm, and more preferably less than 5 nm, and not exceeding a specific value.

[0208] In one embodiment, the present disclosure relates to a multilayer sintered ceramic body and / or a component made therefrom, the multilayer sintered ceramic body having at least one first layer 100 comprising polycrystalline YAG, the at least one first layer having a plasma-facing surface 106 that provides a maximum height Sz according to ISO standard 25178-2-2012 of less than 5.0 μm, more preferably less than 4.0 μm, most preferably less than 3.5 μm, more preferably less than 2.5 μm, more preferably less than 2 μm, and more preferably less than 1.5 μm and not exceeding a specific value before an etching or deposition process.

[0209] In one embodiment, the present disclosure relates to a multilayer sintered ceramic body and / or a component made therefrom having at least one first layer 100 comprising polycrystalline YAG, the at least one first layer having a surface roughness of less than 1500×10 Å according to ISO standard 25178-2-2012, section 4.1.7, prior to an etching or deposition process. -5 , more preferably less than 1200×10 -5 , more preferably less than 1000×10 -5 , more preferably less than 800×10 -5 , more preferably less than 600×10 -5 And more preferably less than 400×10 -5 and the plasma-facing surface 106 has an extended interface area Sdr that does not exceed a specific value.

[0210] In one embodiment, the present disclosure relates to a multilayer sintered ceramic body and / or a component made therefrom, the multilayer sintered ceramic body having at least one first layer comprising polycrystalline YAG, the at least one first layer having a surface roughness according to ISO standard 25178-2-2012 section 4.1.7 of 0.0005 μm to 2 μm, preferably 0.0005 μm to 1.5 μm, preferably 0.0005 μm to 1 μm, preferably 0.0005 μm to 0.75 μm, preferably 0.0005 μm to 0.5 μm, preferably 0.0005 μm to 0.25 μm, preferably 0.0 The plasma-facing surface 106 has an arithmetic mean height Sa of preferably 0.005 μm to 0.125 μm, preferably 0.0005 μm to 0.075 μm, preferably 0.0005 μm to 0.050 μm, preferably 0.0005 μm to 0.025 μm, preferably 0.0005 μm to 0.020 μm, preferably 0.0005 μm to 0.015 μm, preferably 0.0005 μm to 0.010 μm, preferably 0.001 μm to 0.030 μm, preferably 0.001 μm to 0.020 μm, preferably 0.001 μm to 0.010 μm and preferably about 0.008 μm and not exceeding a specific value.

[0211] In one embodiment, the present disclosure relates to a multilayer sintered ceramic body and / or a component made therefrom, having at least one first layer comprising polycrystalline YAG, the at least one first layer having a plasma-facing surface 106 that provides, after an etching or deposition process as disclosed herein, a surface roughness according to ISO standard 25178-2-2012, section 4.1.7 of less than 3.8 μm, preferably less than 2.8 μm, preferably less than 2.5 μm, preferably 0.1 μm to 2.5 μm, preferably 0.1 μm to 1.5 μm, preferably 0.1 μm to 1.0 μm, preferably 0.1 μm to 0.5 μm, and preferably about 0.1 μm to 0.3 μm, and not exceeding a specific value.

[0212] In one embodiment, the present disclosure relates to a multilayer sintered ceramic body and / or a component made therefrom having at least one first layer comprising polycrystalline YAG, the at least one first layer having a surface roughness less than 3000×10 Å according to ISO standard 25178-2-2012, section 4.1.7, after an etching or deposition process as disclosed herein. -5 , more preferably less than 2500×10 -5 , more preferably less than 2000×10 -5 , more preferably less than 1500×10 -5 , more preferably less than 1000×10 -5And more preferably, the plasma-facing surface 106 has an expanded interfacial area Sdr of less than 800×10-5 and not exceeding a specific value. By using the above-described multilayer sintered ceramic body according to the embodiments disclosed herein, a significantly corrosion- and erosion-resistant material is provided that allows for continuous, long-term use as a component in etching and deposition processes. This corrosion- and erosion-resistant material minimizes particle generation through the improved surface characteristics disclosed herein, thereby providing improved performance during use and reducing contamination of semiconductor substrates during processing.

[0213] The starting powders and powder mixtures used to prepare the at least one first layer 100 disclosed herein, having extremely high purity, can provide corrosion and erosion resistance, enabling use as components in semiconductor etching and deposition applications. This high purity provides a chemically inert, plasma-facing surface 106 (the term inert as used herein is intended to mean chemically inactive), which prevents the plasma-facing surface 106 of the at least one first layer 100 from being roughened by halogen-based gaseous species, which can otherwise chemically attack and etch or erode materials made from less pure powders and powder mixtures through ion bombardment. Impurities and contaminants within the at least one first layer 100 act as sites for initiating corrosion and erosion, so high purity (and correspondingly low impurity content, expressed in ppm of contaminants) is preferred within the at least one first layer 100 of the multi-layer, corrosion-resistant sintered ceramic body, particularly on the plasma-facing surface 106. Table 9 lists the impurities of an exemplary powder mixture, according to one embodiment, that is sintered to form the at least one first layer 100, the at least one first layer comprising substantially phase-pure polycrystalline YAG.

[0214] According to the disclosure herein, a multilayer sintered ceramic body having a plasma-facing surface 106 of at least one first layer comprising an yttrium aluminum garnet (YAG) phase in an amount greater than 90% by volume can be formed by in situ reactive sintering during a sintering step by combining the particle size distribution, purity and / or surface area characteristics of a powder mixture as disclosed herein. In embodiments, the powder mixture comprises crystalline powders of yttrium oxide and aluminum oxide. In other embodiments, the powder mixture can be calcined and comprise less than about 10% by volume of YAG, preferably less than 8% by volume of YAG, and preferably less than 5% by volume of YAG in addition to the crystalline powders of yttrium oxide and aluminum oxide; in other embodiments, powder mixtures are disclosed herein that are free of or substantially free of YAG phase (comprising crystalline powders of yttrium oxide and aluminum oxide). In other embodiments, it may be preferred that the powder mixture have a particle size distribution greater than 2 m 2 In other embodiments, it may be preferred that the powder mixture does not contain a specific surface area of ​​about 2 m 2 / g and greater YAG phase to form at least one first layer of a multi-layer sintered ceramic body comprising YAG by an in-situ, reactive phase sintering process as disclosed herein. All purity measurements disclosed herein were measured above the reporting limit of the specific element and were completed using ICP-MS (inductively coupled plasma mass spectrometry) from an Agilent 7900 ICP-MS model G8403. The liquid sample was introduced into the ICP-MS in the form of a fine aerosol, which was ionized in a plasma discharge and subsequently separated using a quadrupole mass analyzer known to those skilled in the art. The detection limit for identifying the presence of lighter elements using the ICP-MS method as disclosed herein is higher than the reporting limit for heavier elements. In other words, heavier elements such as Sc and higher are detected with higher accuracy (e.g., as low as 0.06 ppm) than those lighter elements, such as those from Li to Al (e.g., detected with an accuracy as low as 0.7 ppm). Thus, the impurity content of powders containing lighter elements such as Li to Al can be determined to be about 0.7 ppm and greater, and the impurity content of heavier elements from Sc (scandium) to U (uranium) can be determined to be about 0.06 ppm and greater. Using the ICPMS method as disclosed herein, silicon dioxide can be detected in amounts as low as about 14 ppm, while K (potassium) and Ca (calcium) can be identified in amounts of 1.4 ppm and greater. Iron can be accurately detected in amounts as low as 0.14 ppm and greater. The total impurity content as disclosed herein does not include silicon dioxide.

[0215] As measured using ICPMS, the plasma-facing surface 106 of the at least one first layer 100 comprising polycrystalline YAG may have a total impurity content of less than 100 ppm, preferably less than 75 ppm, less than 50 ppm, preferably less than 25 ppm, preferably less than 15 ppm, preferably less than 10 ppm, preferably less than 8 ppm, preferably less than 5 ppm, preferably from 5 ppm to 30 ppm, preferably from 5 ppm to 20 ppm, relative to the total mass of the at least one first layer comprising polycrystalline YAG. The total impurity content disclosed herein does not include Si in the form of silicon dioxide.

[0216] The detection limit for identifying the presence of lighter elements using the ICP-MS method as disclosed herein is higher than the reporting limit for heavier elements. In other words, heavier elements such as Sc and higher are detected with higher precision (e.g., as low as 0.06ppm) compared to those lighter elements such as from Li to Al (e.g., detected with an accuracy as low as 0.7ppm). Therefore, the impurity content of those powders containing lighter elements such as from Li to Al can be determined to be about 0.7ppm and greater, and the impurity content of heavier elements from Sc (scandium) to U (uranium) can be determined to be about 0.06ppm and greater. Using the ICPMS method as disclosed herein, silica as low as about 14ppm can be detected, while K (potassium) and Ca (calcium) of 1.4ppm and greater can be identified. Iron can be accurately detected in an amount as low as 0.14ppm.

[0217] Sintering aids such as SiO2, MgO, CaO, Li2O, and LiF are known to promote densification, and LiF in particular is known to promote grain growth, thereby increasing grain size in YAG and spinel. However, these sintering aids can reduce corrosion resistance, strength, and performance in etching and deposition applications. Therefore, in some embodiments, at least one first layer 100 of a multilayer sintered ceramic body as disclosed herein can be formed from at least one powder mixture having a calcium oxide, magnesium oxide, lithium oxide, and / or lithium fluoride content of about 2 ppm and less, each relative to the total mass of the powder mixture. The high purity of the powder mixture (which can be calcined and then sintered using the methods disclosed herein) is thereby transferred to the multilayer sintered ceramic body. In embodiments as disclosed herein, for example, a multilayer sintered ceramic body may have at least one first layer 100 comprising at least one crystalline phase of a ceramic material selected from the group consisting of YAG, magnesium aluminate spinel, and yttrium oxide and zirconium oxide, wherein each of the at least one first layer 100 comprises silicon dioxide in an amount of 14 ppm to 100 ppm, preferably 14 ppm to 75 ppm, preferably 14 ppm to 50 ppm, preferably 14 ppm to 25 ppm, preferably 14 ppm to 20 ppm, preferably about 14 ppm, each relative to the mass of the at least one first layer 100. In other embodiments, each of the at least one first layer 100 may comprise at least one of magnesium oxide, lithium oxide / lithium fluoride, and / or calcium oxide in an amount of about 2 ppm to 100 ppm, preferably about 2 ppm to 75 ppm, preferably about 2 ppm to 50 ppm, preferably about 2 ppm to 25 ppm, preferably about 2 ppm to 20 ppm, preferably about 2 ppm to 10 ppm, each relative to the mass of the at least one first layer 100. In order to improve strength and provide chemical inertness in the at least one first layer 100 comprising at least one crystalline phase of a ceramic material selected from the group consisting of YAG, magnesium aluminate spinel, and zirconium oxide and aluminum oxide, it is preferred that each of the at least one first layer 100 does not contain Li or LiF in an amount greater than about 2 ppm, each relative to the mass of the at least one first layer 100. Therefore, in further embodiments, each of the at least one first layer 100 comprising at least one crystalline phase of a ceramic material selected from the group consisting of YAG, magnesium aluminate spinel, and zirconium oxide and aluminum oxide may contain lithium fluoride, calcium oxide, and / or magnesium oxide in an amount of about 2 ppm to 100 ppm, preferably about 2 ppm to 75 ppm, preferably about 2 ppm to 50 ppm, preferably about 2 ppm to 25 ppm, preferably about 2 ppm to 20 ppm, each relative to the mass of the at least one first layer 100.

[0218] In preferred embodiments, the at least one first layer comprising polycrystalline YAG may have a purity of 99.99% and higher, preferably 99.995% and higher, each relative to material having 100% purity, as measured using the ICPMS method as disclosed herein.

[0219] In an embodiment, each of the at least one first layer 100 comprising at least one polycrystalline ceramic material selected from the group consisting of YAG, magnesium aluminate spinel, and yttria and zirconium oxide may contain Si in the form of silicon dioxide in an amount of 14 ppm to 100 ppm, preferably 14 ppm to 75 ppm, preferably 14 ppm to 50 ppm, preferably 14 ppm to 25 ppm, preferably 14 ppm to 20 ppm, and preferably about 14 ppm, each relative to the total mass of the at least one first layer.

[0220] In the embodiments of the multilayer sintered ceramic bodies disclosed herein, each of the at least one first layer 100 comprising at least one polycrystalline ceramic material selected from the group consisting of YAG, magnesium aluminate spinel, and yttria and zirconia may be made with an optional dopant, such as a rare earth oxide selected from the group consisting of Sc, La, Er, Ce, Cr, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, and Lu, and oxides and combinations thereof, in an amount of > 0.002% by weight, preferably > 0.0035% by weight, preferably > 0.005 wt% and preferably > 0.0075% by weight of the dopant can be added to the starting powder or powder mixture in step a, b or c.

[0221] In the embodiments of the multi-layer sintered ceramic bodies disclosed herein, at least one first layer 100 of the aforementioned ceramic sintered body may be made with an optional dopant such as a rare earth oxide selected from the group consisting of Sc, La, Er, Ce, Cr, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb and Lu, and oxides and combinations thereof, in an amount of < 0.05% by weight, preferably < 0.03% by weight, preferably < 0.01% by weight and preferably 0.002% to 0.02% by weight, of dopant can be added to the starting powder or powder mixture in step a, b or c.

[0222] In embodiments of the multilayer sintered ceramic bodies disclosed herein, the at least one first layer 100 comprising at least one polycrystalline ceramic material selected from the group consisting of YAG, magnesium aluminate spinel, and yttrium oxide and zirconium oxide can be formed without the aforementioned dopants. In particular, for semiconductor chamber applications requiring chemical inertness and corrosion and erosion resistance combined with high strength, it may be preferred that each of the at least one first layer 100 of the multilayer sintered ceramic body comprising at least one polycrystalline ceramic material selected from the group consisting of YAG, magnesium aluminate spinel, and yttrium oxide and zirconium oxide is free of or substantially free of dopants. Thus, in certain embodiments, the multilayer sintered ceramic body having at least one first layer 100 comprising at least one polycrystalline ceramic material selected from the group consisting of YAG, magnesium aluminate spinel, and yttrium oxide and zirconium oxide is substantially free of or free of at least one or all of the aforementioned dopants.

[0223] According to some embodiments, excess yttrium oxide and / or aluminum oxide within the polycrystalline YAG layer 100 is not considered a dopant or sintering aid, as long as they remain in the at least one first layer. The disclosed high purity and corresponding low impurities of the plasma-facing surface 106 of the at least one first layer can achieve the desired particle generation and corrosion and erosion reduction required for use in semiconductor reactors. For the at least one first layer 100 comprising polycrystalline YAG, purity can be measured, for example, to be 99.99% and higher, preferably 99.995% and higher, preferably 99.999% and higher, preferably 99.9995% and higher, and preferably about 99.9999%.

[0224] The dielectric loss / tan δ of the at least one first layer 100 and the at least one second layer 102 of polycrystalline YAG are listed in Table 8 below. The high purity of the respective layers constituting the multi-layer sintered ceramic body provides a dielectric loss / tan δ of 5.5×10 -3 and smaller and less than 1×10 at 1 GHz -4 and a low loss tangent of less than 0.0007 for at least one second layer comprising alumina and about 16 volume percent partially stabilized zirconia.The measurements were performed on an exemplary solid body of each material.

[0225] Table 8

[0226] Material frequency Dielectric constant Loss tangent YAG 1MHz 11.56 <0.0001 YAG 1MHz 11.65 0.0055 YAG 1GHz 11.03 <0.0001 YAG 1GHz 11.06 <0.0001 Alumina 16% by volume zirconia 1MHz 12 <0.0007

[0227] However, these corrosion and erosion resistant materials present challenges to sintering to the high densities required for semiconductor etching and deposition chamber applications.Thus, pressure assisted sintering methods are generally required, and in preferred embodiments, pressure and current assisted sintering methods are required.

[0228] According to another embodiment, a monolithic multi-layer sintered ceramic body is disclosed herein, comprising at least one first layer 100 comprising magnesium aluminate spinel; at least one second layer 102 comprising alumina and zirconia, wherein the zirconia comprises at least one of stabilized zirconia and partially stabilized zirconia; and at least one third layer 103 comprising a multiphase layer comprising at least YAG, alumina, and zirconia, wherein the zirconia comprises at least one of unstabilized zirconia, stabilized zirconia, and partially stabilized zirconia, wherein the body is subjected to a sintering test according to ASTM F 1500, wherein the sintering test is conducted at a temperature in the range of 25° C. to 1700° C. or at a temperature in the range of 200° C. to 1400° C. The absolute value of the difference in coefficient of thermal expansion (CTE) between at least one first layer, at least one second layer and at least one third layer measured by E228-17 is 0 to 0.75×10-6 / °C, preferably 0 to 0.7×10-6 / °C, preferably 0 to 0.6×10-6 / °C, preferably 0 to 0.5×10-6 / °C, preferably 0 to 0.45×10-6 / °C, preferably 0 to 0.4×10-6 / °C, Preferably 0 to 0.35×10-6 / °C, preferably 0 to 0.3×10-6 / °C, preferably 0 to 0.25×10-6 / °C, preferably 0 to 0.2×10-6 / °C, preferably 0 to 0.15×10-6 / °C, preferably 0 to 0.1×10-6 / °C, preferably 0 to 0.08×10-6 / °C, preferably 0 to 0.04×10-6 / °C, and preferably 0 to 0.02×10-6 / °C. These ranges of absolute values ​​of the CTE difference between the at least one first layer comprising magnesium aluminate spinel and the at least one second layer and the at least one third layer correspond to CTE differences of 9% and less, preferably 7% and less, preferably 5% and less, preferably 3% and less, preferably 2% and less, preferably 1.5% and less, preferably 1% and less, preferably 0.5% and less, and preferably 0.1% and less between any of the at least one first layer, at least one second layer, and at least one third layer as a percentage of the at least one first layer, at least one second layer, and at least one third layer (as measured relative to the at least one first layer 100 comprising magnesium aluminate spinel). In the temperature range of ambient temperature (or at least from 200° C. as depicted in the figures) to about 1700° C. (or at least to 1400° C. as depicted in the figures), the at least one first layer, at least one second layer, and at least one third layer are CTE matched within the disclosed ranges to form a monolithic multilayer sintered ceramic body.

[0229] Figure 17a ), Figure 17b )and Figure 17c) shows CTE measurements of exemplary materials for forming at least one first layer and at least one second layer of a monolithic, multi-layer sintered ceramic body according to one embodiment over a temperature range from ambient temperature (or at least from 200° C. as depicted in the figures) to about 1700° C. (or at least to 1400° C. as depicted in the figures). All CTE measurements disclosed herein were performed according to ASTM E228-17. CTE measurements were performed on exemplary body materials. Figure 17a ) depicts a first layer 100 of magnesium aluminate spinel and a second layer 102 comprising aluminum oxide and zirconium oxide, wherein the zirconium oxide comprises at least one of stabilized zirconium oxide and partially stabilized zirconium oxide in an amount of about 25 volume percent. Figure 17b ) depicts a spinel first layer and a second layer 102 comprising alumina and zirconia, wherein the zirconia comprises at least one of stabilized zirconia and partially stabilized zirconia in an amount of about 16 volume % zirconia with the balance being alumina. Figure 17c ) depicts CTE measurements of at least one first layer 100 of magnesium aluminate spinel and at least one second layer 102 comprising alumina and zirconia over a temperature range of 200° C. to 1400° C., wherein the zirconia comprises at least one of stabilized zirconia and partially stabilized zirconia in an amount of approximately 20% by volume zirconia with the balance being alumina. The composition of the at least one second layer 102 and the at least one third layer 103 of the ZTA can be varied to match the CTE of the at least one first layer 100 comprising spinel. The composition range of the at least one second layer 102 comprising zirconium oxide and aluminum oxide (16% to 25% by volume zirconia with the balance being alumina) can be suitable for CTE matching the at least one first layer 100 comprising spinel. Thus, disclosed herein is a multilayer sintered ceramic body comprising at least one second layer comprising about 16% to about 25% zirconium oxide (with the balance being alumina); at least one first layer 100 comprising magnesium aluminate spinel; and at least one third layer having a CTE matched to the at least one first layer and at least one second layer. To more closely match the CTE of the spinel first layer 100, second layer 102, and third layer 103 according to one embodiment, the second layer 102 comprises about 15% to about 25%, preferably about 18% to about 20%, and more preferably about 20% zirconium oxide (with the balance being alumina), each by volume. These composition ranges for the at least one second layer 102 can be measured in accordance with ASTM E228-17 at temperatures ranging from ambient temperature (or at least from 200° C. as depicted in the accompanying drawings) to about 1700° C. (or at least to 1400° C. as depicted in the accompanying drawings) at about 0.45×10 -6 / ℃ and less, preferably about 0.4×10 -6 / ℃ and less, preferably about 0.3×10 -6 / ℃ and less, preferably about 0.25×10 -6 / ℃ and less, preferably about 0.2×10 -6 / ℃ and less, preferably 0.15×10 -6 / ℃ and less, preferably 0.1×10 -6 / ° C and less, preferably 0.08 × 10-6 / ° C and less, preferably 0.06 × 10-6 / ° C and less, preferably 0.04 × 10-6 / ° C and less, preferably 0.02 × 10-6 / ° C and less, and preferably 0.01 × 10-6 / ° C and less provide CTE matching with the at least one first layer 100 of spinel. As a percentage relative to the at least one first layer, the CTE difference (according to one embodiment, between any of the first, second, and third layers) can be 6% and less, preferably 5% and less, preferably 4% and less, preferably 3% and less, preferably 2% and less, preferably 1.5% and less, preferably 1% and less, preferably 0.5% and less, and preferably 0.25% and less of the at least one first layer, at least one second layer, and at least one third layer (as measured relative to the at least one first layer 100 comprising spinel). According to the methods and stabilizing compounds as disclosed herein, the zirconia can be at least one of stabilized zirconia and partially stabilized zirconia. The CTE variation between the at least one second layer 102 (comprising zirconium oxide and aluminum oxide), the at least one first layer (comprising magnesium aluminate spinel), and the at least one third layer (comprising a combination of the first and second layers) is within the disclosed range for successfully manufacturing a monolithic multilayer sintered ceramic body as disclosed herein.

[0230] Figure 18 Depicted are x-ray diffraction results of a calcined powder mixture (calcined at 850° C. for 4 hours) of magnesium oxide and aluminum oxide (with a small amount of spinel phase formed) that batch-forms (upon sintering) at least one first layer 100 comprising a magnesium aluminate spinel phase MgAl 2 O 4 according to an embodiment of a monolithic multilayer sintered ceramic body as disclosed herein. The spinel phase is formed by an in situ reactive sintering step from a powder mixture of starting powders comprising magnesium oxide and aluminum oxide. In some preferred embodiments, the at least one first layer 100 comprising spinel is substantially free of or free of dopants, and is substantially free of or free of sintering aids, and is substantially free of or free of LiF. In other embodiments, the spinel first layer may contain a sintering aid in an amount as disclosed herein (in addition to magnesium oxide, which is the primary component of the spinel).

[0231] Figure 19A 1000× SEM image of a high-density sintered microstructure of at least one first layer 100 comprising magnesium aluminate spinel according to one embodiment as disclosed herein is shown. The at least one first layer 100 comprising spinel is free or substantially free of dopants, sintering aids, and LiF as disclosed herein. An almost completely dense microstructure with minimal porosity is depicted.

[0232] According to this embodiment where the at least one first layer comprises spinel, a Sa of about 5 nm to about 20 nm can be measured across the surface using the surface roughness measurement method as disclosed herein.

[0233] According to another embodiment, a monolithic, multi-layer sintered ceramic body is disclosed herein, comprising at least one first layer comprising at least one polycrystalline ceramic material comprising yttria and zirconia, wherein the zirconia is present in an amount not less than 10 mol% and not more than 25 mol%; at least one second layer 102 comprising alumina and zirconia, wherein the zirconia comprises at least one of stabilized zirconia and partially stabilized zirconia; and at least one third layer 103 comprising a plurality of phases of at least YAG, alumina, and zirconia, wherein the yttria and zirconia are ... third layer 103 comprising a plurality of phases of at least YAG, alumina, and zirconia, wherein the yttria and zirconia are present in an amount not less than 10 mol% and not more than 25 mol%; at least one third layer 103 comprising a plurality of phases of at least YAG, alumina, and zirconia, wherein the yttria and zirconia are present in an amount not less than 10 mol% and not more than 25 mol%; at least one third layer 103 comprising a plurality of phases of at least YAG, alumina, and zirconia, wherein the yttria and zirconia are present in an amount not less than 10 mol% and not more than 25 mol% The absolute value of the difference in coefficient of thermal expansion (CTE) between at least one first layer, at least one second layer and at least one third layer measured by E228-17 is 0 to 0.75×10-6 / °C, preferably 0 to 0.7×10-6 / °C, preferably 0 to 0.6×10-6 / °C, preferably 0 to 0.5×10-6 / °C, preferably 0 to 0.45×10-6 / °C, preferably 0 to 0.4×10-6 / °C, preferably 0 to 0.35×10-6 / °C , preferably 0 to 0.3×10-6 / ℃, preferably 0 to 0.25×10-6 / ℃, preferably 0 to 0.2×10-6 / ℃, preferably 0 to 0.15×10-6 / ℃, preferably 0 to 0.1×10-6 / ℃, preferably 0 to 0.08×10-6 / ℃, preferably 0 to 0.06×10-6 / ℃, preferably 0 to 0.04×10-6 / ℃, preferably 0 to 0.02×10-6 / ℃, preferably 0 to 0.01×10-6 / ℃. These ranges of absolute values ​​of the CTE difference between the at least one first layer comprising yttria and zirconium oxide (wherein zirconium oxide is present in an amount of not less than 10 mol% and not more than 25 mol%) and the second and third layers correspond to CTE differences of 8% and less, preferably 6.5% and less, preferably 5% and less, preferably 4% and less, preferably 3% and less, preferably 2% and less, preferably 1% and less, preferably 0.5% and less, and preferably 0.1% and less between any of the at least one first layer, at least one second layer, and at least one third layer, as a percentage (as measured relative to the at least one first layer 100). Within a temperature range of ambient temperature (or at least from 200° C. as depicted in the figures) to about 1700° C. (or at least to 1400° C. as depicted in the figures), the at least one first layer, at least one second layer, and at least one third layer are CTE matched within the disclosed ranges to form a unitary multilayer sintered ceramic body.

[0234] Figure 20a ), Figure 20b )and Figure 20c) shows CTE measurements of exemplary materials for forming at least one first layer and at least one second layer of a monolithic, multi-layer sintered ceramic body according to one embodiment over a temperature range from ambient temperature (or at least from 200° C. as depicted in the figures) to about 1700° C. (or at least to 1400° C. as depicted in the figures). All CTE measurements disclosed herein were performed according to ASTM E228-17. CTE measurements were performed on exemplary body materials. Figure 20a ) depicts at least one first layer 100 comprising approximately 20 mol% zirconium oxide with the balance being yttria and at least one second layer 102 having 16 volume % zirconium oxide with the balance being aluminum oxide. Figure 20b ) depicts at least one first layer 100 comprising approximately 20 mol% zirconium oxide with the balance being yttria and at least one second layer 102 having approximately 20 volume % of at least one of stabilized zirconium oxide and stabilized zirconium oxide with the balance being alumina. Figure 20c ) depicts at least one first layer 100 comprising approximately 25 mol% zirconium oxide with the balance being yttria and at least one second layer 102 comprising approximately 25 volume % zirconium oxide (relative to the volume of the at least one second layer) with the balance being aluminum oxide. Variations of this embodiment may include at least one first layer 100 comprising at least one crystalline phase of a ceramic material comprising yttria and zirconium oxide, wherein the zirconium oxide is present in an amount of not less than 10 mol% ZrO2 and not more than 25 mol% ZrO2, preferably not less than 12 mol% and not more than 23 mol% ZrO2, preferably not less than 15 mol% and not more than 25 mol% ZrO2, preferably not less than 18 mol% and not more than 25 mol% ZrO2, preferably not less than 10 mol% and not more than 23 mol% ZrO2, preferably not less than 10 mol% and not more than 20 mol% ZrO2, preferably not less than 15 mol% and preferably not more than 23 mol% ZrO2, and the balance comprising Y2O3. These compositions of the at least one first layer 100 can be combined with the compositions of the at least one second layer 102 and the at least one third layer 103 as disclosed herein, wherein the at least one second layer and the at least one third layer have suitable compositions (of zirconium oxide and aluminum oxide) to match the CTE of the at least one first layer 100 comprising at least one crystalline phase of yttrium oxide and zirconium oxide. In embodiments, the at least one first layer 100 may comprise at least one crystalline phase of yttrium oxide and zirconium oxide selected from a C-type solid solution, or a combination of a fluorite solid solution and a C-type solid solution, or a Zr3Y4O 12The present invention relates to a group consisting of a combination of a compound phase and a C-type solid solution. A C-type solid solution refers to a rare earth yttria-type solid solution. These crystalline phases are consistent with the composition ranges disclosed in "Phase Relationships in the Yttria-Rich Portion of the Yttria-Zirconia System" (J. Mater. Sci 12 (1977) 311-316, HG Scott). In one embodiment, the CTE of at least one first layer 100 (comprising 10 to 25 mol% zirconia and the balance yttria) can match the CTE of at least one second layer 102 comprising approximately 16 to 25 volume% zirconia (relative to the volume of the at least one second layer) and the balance being alumina. In this embodiment, the CTE of at least one first layer 100 (comprising 10 to 25 mol% zirconia with the balance being yttria) can be matched to the CTE of at least one second layer 102 comprising about 16 to about 25 vol% of at least one of partially stabilized zirconia and stabilized zirconia with the balance being alumina. Thus, disclosed herein is a multilayer sintered ceramic body 98 comprising at least one second layer 102 comprising about 16 to about 25 vol% of at least one of partially stabilized zirconia and stabilized zirconia (with the balance being alumina), and at least one first layer 100 comprising 10 to 25 mol% zirconia with the balance being yttria. In a preferred embodiment, to more closely match the CTE of the at least one first layer 100 (comprising 10 to 25 mol% zirconia with the balance being yttria) and the at least one second layer 102 (comprising alumina and at least one of partially stabilized zirconia and stabilized zirconia), the at least one second layer comprises zirconium oxide in an amount of about 16% to about 25%, preferably about 20% to about 25%, preferably about 22% to about 25%, and more preferably about 20% by volume of at least one of partially stabilized zirconia and stabilized zirconia (with the balance being alumina), relative to the volume of the at least one second layer 102. These compositional ranges for the at least one second layer 102 are measured in accordance with ASTM E228-17 over a temperature range of about 0.55×10 -6 / ℃ and less, preferably 0.5×10 -6 / ℃ and less, preferably about 0.4×10 -6 / ℃ and less, preferably about 0.3×10 -6 / ℃ and less, preferably about 0.2×10 -6 / ℃ and less, preferably 0.15×10 -6 / ° C and less provides CTE matching with the at least one first layer 100 (comprising 10 mol% to 25 mol% zirconium oxide and the balance being yttria). According to the methods and stabilizing compounds disclosed herein, the zirconium oxide comprising the at least one second layer 102 can be at least one of stabilized zirconium oxide and partially stabilized zirconium oxide.

[0235] In embodiments, the at least one first layer 100 comprising at least one crystalline phase of yttria and zirconia is substantially free of or free of dopants and / or substantially free of or free of sintering aids, wherein the zirconia is present in an amount of not less than 10 mol% ZrO2 and not more than 25 mol% ZrO2. In other embodiments, the at least one first layer 100 comprising at least one crystalline phase of yttria and zirconia in the disclosed amounts may include sintering aids and / or dopants in the amounts disclosed herein. The zirconia starting powder comprising at least one first phase 100 comprising yttria and zirconia in the disclosed amounts may include at least one selected from the group consisting of unstabilized zirconia, partially stabilized zirconia, and stabilized zirconia.

[0236] Figure 21 a) shows an SEM image showing a nonlinear interface 104 of a monolithic multilayer sintered ceramic body 98 according to one embodiment, wherein at least one first layer 100 comprises at least one crystalline phase of a ceramic material, the at least one crystalline phase comprising yttria and zirconia, wherein the zirconia is present in an amount of about 20 mol % and the balance being yttria. In certain embodiments, the zirconia of the at least one first layer may be partially stabilized zirconia and comprise about 3 mol % yttria as a stabilizing compound. In other embodiments, the zirconia of the at least one first layer may comprise at least one of unstabilized zirconia, partially stabilized zirconia, and stabilized zirconia. In embodiments, the at least one first layer 100 may include a reaction layer 108 adjacent to the at least one second layer 102, wherein the at least one second layer 102 and the reaction layer 108 form a nonlinear interface 104 between the layers. As Figure 21 As can be seen from the SEM results of , the reaction layer 108 is highly dense and has minimal porosity. As measured from the SEM imaging, the reaction layer 108 may have a thickness of 10 μm to 30 μm, preferably 15 μm to 30 μm, preferably 20 μm to 30 μm, preferably 25 μm to 30 μm, preferably about 20 μm. The adhesion strength of the nonlinear interface 104 may be enhanced by the reaction layer 108. In an embodiment, the reaction layer 108 may include at least one crystalline phase selected from the group consisting of YAG, YAP, YAM, a cubic crystal phase (including a solid solution of at least two of yttrium oxide, aluminum oxide, and zirconium oxide), a cubic fluorite crystal phase (including a solid solution of at least two of yttrium oxide, aluminum oxide, and zirconium oxide), and combinations thereof. Figure 21b) depicts a high density sintered microstructure of the plasma facing surface 106 of at least one first layer 100 comprising approximately 20 mol% zirconium oxide with the balance being yttria. An almost fully dense microstructure with minimal porosity is depicted.

[0237] According to one embodiment of the invention, the at least one first layer comprises a solid solution of 80 mol % yttrium oxide and 20 mol % zirconium oxide, an average Ra of 10 nm to 25 nm is measured in 5 measurements.

[0238] As known to those skilled in the art, multilayer sintered bodies are typically formed from prefabricated layers or tapes that are laminated and co-sintered or laminated or deposited onto a sintered substrate and sintered. However, these multilayer laminates often suffer from delamination at the interfaces between the layers due to insufficient interfacial bonding between the layers, resulting in flaking and particle release during use in semiconductor reactors. Typically, the interfaces of these laminates are linear and therefore do not provide the advantages of interlocking, increased adhesion / bonding strength, and enhanced toughness of the multiphase second interface 105, which are characteristic of the monolithic multilayer sintered ceramic bodies disclosed herein.

[0239] Disclosed herein is a multilayer sintered ceramic body comprising at least one first layer 100 and at least one second layer 102, the at least one first layer and the at least one second layer being contiguous and bounded by a nonlinear interface 104, such as Figure 22 a) and Figure 22 b) is depicted in the schematic diagram. Figure 22 a) and Figure 22 b), a nonlinear interface 105 is disposed between adjacent layers 102 and 103. As shown, the nonlinear interface 104 (as described in more detail herein) can provide enhanced adhesion between the at least one first layer 100 and the at least one second layer 102. This improved adhesion can be achieved by a number of factors, including increased interface length and associated increased interface area, tortuosity (T), the arithmetic mean of the interface (the distance of the interface from the mean interface line), nonlinearity, and an interlocking effect provided by the morphology of the interface 104.

[0240] The interfaces of these layers typically have a tortuosity and a nonlinear interface such that the interface layer typically meanders between at least one first layer and a second layer and between at least one second layer and at least one third layer. The tortuosity obtained using calculations as disclosed herein can be between 1.2 and 2.2, and more particularly between 1.4 and 2.0. Measurements for determining tortuosity are described below and are based on the increase in interface length relative to the linear distance of the interface layer. Thus, disclosed herein is a multilayer sintered ceramic body having an interface defined by at least one second layer and at least one first layer and between at least one second layer and at least one third layer, wherein the interface length increases by 20% to 70%, preferably 20% to 60%, preferably 20% to 40%, preferably 30% to 80%, preferably 40% to 80%, and preferably 50% to 70%.

[0241] Accordingly, at least one second layer and at least one first layer and at least one third layer and at least one second layer may contact each other at interfaces having an area commensurate with a maximum dimension of the multilayer sintered ceramic body along the interface layers.

[0242] For a monolithic multilayer sintered body having a maximum dimension of 100 mm to about 625 mm, taking into account the above-mentioned curvature of at least 1.2, at least one second layer and at least one first layer contact each other at a nonlinear interface having a nonlinear interface of at least 113 cm 2 , preferably at least 452cm 2 , preferably at least 1,018 cm 2 and preferably at least 1,810 cm 2 area.

[0243] For a monolithic multilayer sintered body having a maximum dimension of 100 mm to about 625 mm, taking into account the above-mentioned curvature of at least 1.4, at least one second layer and at least one first layer contact each other at a nonlinear interface having a nonlinear interface of at least 153 cm 2 , preferably at least 616cm 2 , preferably at least 1,386 cm 2 and preferably at least 2,464 cm 2 area.

[0244] For a monolithic multilayer sintered body having a maximum dimension of 100 mm to about 625 mm, taking into account the above-mentioned curvature of at most 2.2, at least one second layer and at least one first layer contact each other at a nonlinear interface having a maximum dimension of at most 15,085 cm 2 , preferably up to 14,850 cm 2 , preferably at most 14,128 cm 2 , preferably at most 9,802 cm2 , preferably up to 6,083 cm 2 , preferably at most 3,421 cm 2 and preferably at most 1,520 cm 2 area.

[0245] For a monolithic multilayer sintered body having a maximum dimension of 100 mm to about 625 mm, taking into account the above-mentioned curvature of at most 2.0, at least one second layer and at least one first layer contact each other at a nonlinear interface having a maximum dimension of at most 12,468 cm 2 , preferably up to 12,272 cm 2 , preferably up to 11,676 cm 2 , preferably up to 7,852 cm 2 , preferably up to 5,028 cm 2 , preferably up to 2,828cm 2 and preferably at most 1,256 cm 2 area.

[0246] For a monolithic multilayer sintered body having a maximum dimension of 100 mm to about 625 mm, taking into account the above-mentioned curvature of at least 1.2, at least one second layer and at least one first layer contact each other at a nonlinear interface having a 113 cm 2 to approximately 4,488cm 2 , preferably 113cm 2 to approximately 4,418cm 2 , preferably 113cm 2 to 4,204cm 2 , preferably 113cm 2 to 2,827cm 2 , preferably 113cm 2 to 1,918cm 2 , preferably 113cm 2 Up to 1,018cm 2 , preferably 113cm 2 Up to 452cm 2 , preferably 452cm 2 to approximately 4,488cm 2 , preferably 452cm 2 to approximately 4,418cm 2 , preferably 452cm 2 to 4,203cm 2 , preferably 452cm 2 to 2,827cm 2 , preferably 452cm 2 to 1,810cm 2, preferably 1,018cm 2 to approximately 4,418cm 2 , and preferably 1,810 cm 2 to 4,376cm 2 area.

[0247] For a monolithic multilayer sintered body having a maximum dimension of 100 mm to about 625 mm, taking into account the above-mentioned curvature of at least 1.4, at least one second layer and at least one first layer contact each other at a nonlinear interface having a curvature of 153 cm 2 to approximately 6,110cm 2 , preferably 153cm 2 to approximately 6,013cm 2 , preferably 153cm 2 to 5,722cm 2 , preferably 153cm 2 to 3,847cm 2 , preferably 153cm 2 to 2,464cm 2 , preferably 153cm 2 to 1,386cm 2 , preferably 153cm 2 Up to 616cm 2 , preferably 616cm 2 to approximately 6,110cm 2 , preferably 616cm 2 to approximately 6,013cm 2 , preferably 616cm 2 to 5,722cm 2 , preferably 616cm 2 to 3,847cm 2 , preferably 616cm 2 to 2,464cm 2 , preferably 1,386cm 2 to approximately 6,013cm 2 , and preferably 2,464cm 2 to 5,957cm 2 area.

[0248] For a monolithic multilayer sintered body having a maximum dimension of 100 mm to about 625 mm, taking into account the above-mentioned curvature of at most 2.2, at least one second layer and at least one first layer contact each other at a nonlinear interface having a 378 cm 2 to approximately 15,085cm 2 , preferably 378cm 2 to approximately 14,850cm 2, preferably 378cm 2 to 14,128cm 2 , preferably 378cm 2 to 9,502cm 2 , preferably 378cm 2 to 6,083cm 2 , preferably 378cm 2 to 3,421cm 2 , preferably 378cm 2 Up to 1,520cm 2 , preferably 1,520cm 2 to approximately 15,085cm 2 , preferably 1,520cm 2 to approximately 14,850cm 2 , preferably 1,520cm 2 to 14,128cm 2 , preferably 1,520cm 2 to 9,502cm 2 , preferably 1,1520cm 2 to 6,083cm 2 , preferably 3,421cm 2 to approximately 14,850cm 2 , and preferably 6,083cm 2 to 14,710cm 2 area.

[0249] For a monolithic multilayer sintered body having a maximum dimension of 100 mm to about 625 mm, taking into account the above-mentioned curvature of at most 2.0, at least one second layer and at least one first layer contact each other at a nonlinear interface having a 312 cm 2 to approximately 12,468cm 2 , preferably 312cm 2 to approximately 12,272cm 2 , preferably 312cm 2 to 11,676cm 2 , preferably 312cm 2 to 7,852cm 2 , preferably 312cm 2 to 5,028cm 2 , preferably 312cm 2 to 2,828cm 2 , preferably 312cm 2 to 1,256cm 2 , preferably 1,256cm 2 to approximately 12,468cm 2 , preferably 1,256cm2 to approximately 12,272cm 2 , preferably 1,256cm 2 to 11,676cm 2 , preferably 1,256cm 2 to 7,652cm 2 , preferably 1,256cm 2 to 5,028cm 2 , preferably 2,828cm 2 to approximately 12,272cm 2 , and preferably 5,028cm 2 to 7,294cm 2 area.

[0250] Figure 24 a) and Figure 24 b) shows an SEM image characterizing the interface 104 between the at least one first layer 100 and the at least one second layer 102, wherein the linear distance (L) between the ends is about 54 μm, and the interface length or curve (C) measured along the interface 104 is about 90 μm, as shown in FIG. Figure 24 b). Using calculations as disclosed herein, according to Figure 24 b) has a curvature of about 1.7. Nine SEM images were measured using ImageJ software analysis as disclosed herein. The average interface length was measured to be about 90 μm, indicating that the interface length (C) increased by about 66% relative to the linear distance (L). Therefore, disclosed herein is a multilayer sintered ceramic body having an interface 104 defined by at least one second layer and at least one first layer, wherein the interface length is increased by 20% to 70%, preferably 20% to 60%, preferably 20% to 40%, preferably 30% to 80%, preferably 40% to 80%, preferably 50% to 70%. Accordingly, at least one second layer 102 and at least one first layer 100 may contact each other at the interface, and the interface area is commensurate with the maximum dimension of the multilayer sintered ceramic body. In some embodiments, for an integral multilayer sintered body having a maximum dimension of 100 mm to about 625 mm, at least one second layer 102 and at least one first layer 100 contact each other at a nonlinear interface 104 having a nonlinear interface of about 3,117 cm 2 , preferably about 3,068 cm 2 and smaller, preferably 2,919cm 2 and smaller, preferably 78cm 2 to approximately 3,117cm 2 , preferably 78cm 2 to approximately 3,068cm 2 , preferably 78cm 2 to 2,919cm2 , preferably 78cm 2 to 1,963cm 2 , preferably 78cm 2 to 1,257cm 2 , preferably 78cm 2 to 707cm 2 , preferably 78cm 2 Up to 314cm 2 , preferably 314cm 2 to approximately 3,117cm 2 , preferably 314cm 2 to approximately 3,068cm 2 , preferably 314cm 2 to 2,919cm 2 , preferably 314cm 2 to 1,963cm 2 , preferably 314cm 2 to 1,257cm 2 , preferably 707cm 2 to approximately 3,068cm 2 , and preferably 1257cm 2 to 3,039cm 2 In an embodiment, it is preferred that the first and second layers are in direct contact, forming the nonlinear interface 104, and thus the at least one first layer and the at least one second layer are contiguous layers. In other embodiments, circuitry, heating elements, RF coils / RF antennas, etc. may be positioned between the first and second layers as required for a particular component application, and regardless of these features, at least a portion of the first and second layers may be contiguous or substantially contiguous. This increased interface length and interface area will enhance adhesion at the nonlinear interface 104 between the at least one first layer 100 and the at least one second layer 102.

[0251] Reference again Figure 24 b) The width of the interface layer as shown is typically 1 μm to 200 μm, particularly 5 μm to 100 μm, more particularly 10 μm to 50 μm, and even more particularly 20 μm to 30 μm.

[0252] The volume of the first layer over the width of the aforementioned interface layer has pores with a maximum dimension of less than 5 μm, in particular less than 3 μm, especially less than 1 μm.

[0253] The volume of the first layer over the width of the aforementioned interface layer comprises in particular only pores having a maximum dimension of less than 5 μm, in particular less than 3 μm, in particular less than 1 μm.

[0254] The volume of at least the first layer across the width as disclosed herein has a structure wherein less than 0.2%, more preferably less than 0.15%, most preferably less than 0.1% of the volume is occupied by voids as described above.

[0255] The volume of the second layer over the width of the aforementioned interface layer has pores with a maximum dimension of less than 5 μm, in particular less than 3 μm, especially less than 1 μm.

[0256] The volume of the second layer over the width of the aforementioned interface layer has in particular only pores with a maximum dimension of less than 5 μm, in particular less than 3 μm, in particular less than 1 μm.

[0257] The volume of at least the second layer across the width as disclosed herein has a structure wherein less than 0.2%, more preferably less than 0.15%, most preferably less than 0.1% of the volume is occupied by voids as described above.

[0258] Figure 23 a) shows a 500× SEM micrograph of a nonlinear interface 104 of a multilayer sintered ceramic body, wherein the nonlinear interface 104 defined by at least one second layer 102 and at least one first layer 100 is an irregular, nonlinear boundary that may include a retrograde angle in embodiments. Figure 23 In some embodiments depicted in a), the interface can include at least one dovetail structure and / or at least a portion of a dovetail structure. In other embodiments, at least a portion of the interface can include a trapezoidal shape. As disclosed herein, tortuosity (T) is mathematically defined as the ratio of the length C of a curve (interface) to the linear distance L between its ends, such that T = C / L. Figure 23 The image of a) was measured to have a tortuosity of 2.7. As measured using the SEM and image processing methods as disclosed herein (measured within ImageJ software), the nonlinear interface 104 as disclosed herein can have a tortuosity T of greater than 1.02 to about 1.5, preferably greater than 1.02 to about 2.0, preferably greater than 1.02 to about 2.5, preferably greater than 1.02 to about 3.0, preferably 1.1 to about 3.0, preferably 1.3 to about 3, and preferably 1.5 to 2.7.

[0259] Straight-line interfaces (as is typical for laminates and structures using pre-sintered bodies with multiple layers applied thereto) have a curvature of about 1 to 1.02. The increased curvature of the interface 104 of the multilayer body as disclosed herein provides an interlocking effect between the layers, thereby increasing the adhesion strength, resulting in an inseparable, integral multilayer ceramic sintered body.

[0260] Figure 23 b) depicts the average interface line (IL) of the nonlinear interface 104 as calculated by SEM and image processing methods. Figure 23The exemplary SEM image of b) was imported into ImageJ software, and the linear equation of the average interface line (IL) was obtained using the x / y coordinates corresponding to the points along the interface, as Figure 23 b), and the nonlinear interface 104 is characterized by the distance of the nonlinear interface 104 from the average interface line (IL). The distance (D) of the interface 104 from the average interface line (IL) varies by 10 μm to 100 μm, preferably 20 μm to 100 μm, preferably 30 μm to 100 μm, preferably 40 μm to 100 μm, 50 μm to 100 μm, and preferably 25 μm to 85 μm, as measured using SEM and image processing. Increasing the distance (D) from the average interface line (IL) can help enhance the adhesion and interlocking effect of the multilayer sintered ceramic body disclosed herein.

[0261] These reverse or inverse angles, features, and structures may provide an anchoring effect, thereby increasing interfacial tensile strength and adhesion across the interface 104 defined by the at least one second layer 102 and the at least one first layer 100 .

[0262] In comparison, Figure 5 The interface of a prior art sample is depicted where it is possible to first sinter layer or substrate B to form a solid body, then deposit layer D on substrate B, and bond the two over time, temperature, and pressure. A substantially linear interface with no retrograde or interface angle and minimal or no increase in interface length is evident. The tortuosity measurements were calculated as disclosed herein (using Figure 5 The length (C) of the curve (interface) and the linear distance L between its ends were measured from the SEM image imported into the ImageJ image processing software as disclosed herein. The curvature (T) of the prior art laminate was calculated to be less than about 1.02. Therefore, the interface of the embodiment of the multilayer body as known in the art cannot provide the beneficial features of enhanced interlayer adhesion and interlocking effect of the subject monolithic multilayer sintered ceramic body as disclosed herein. Figure 5 The depicted bright area (center right of the image) corresponds to the metal layer.

[0263] like Figure 5 As depicted in the prior art laminate of FIG, there is a significant grain size variation between layers B and D. Layer B has large grains of approximately 20 to 30 μm, which may indicate extensive thermal history, such as multiple sintering processes. Layer D has grains of approximately 2 to 5 μm, which indicates much less grain growth typically caused by thermal history and sintering. This grain size difference may indicate a lamination or deposition process, whereby layer D was deposited or laminated onto layer B and subsequently sintered to form the laminate or laminate.

[0264] The high density required for layer B (to impart mechanical strength, high Young's modulus, and other properties) requires an extended sintering time and high temperature, which results in excessive grain growth. Layer D is then bonded to substrate B at a lower temperature for a shorter duration, so that layer D may not experience excessive grain growth from substrate B. This produces a layered structure with a significant difference in grain size. The grain size was measured (using the Heyn line intercept method, as known to those skilled in the art), and was found to be approximately 12 μm and 4 μm for substrate B and layer D, respectively. This grain size difference can cause inconsistencies in properties (such as mechanical strength, Young's modulus, dielectric loss, and other properties) between the two bodies, which can lead to fractures and / or cracks.

[0265] In contrast, grain size measurements were performed on a multilayer sintered ceramic body according to one embodiment, comprising at least one first layer comprising YAG and at least one second layer comprising alumina, wherein the alumina comprises at least one of stabilized zirconia and partially stabilized zirconia in an amount of approximately 16% by volume. The grain sizes of the at least one first layer of YAG and the at least one second layer were measured to be approximately 0.78 μm and 0.74 μm, respectively. These differences are within the accuracy of the measurements, and thus, a multilayer sintered ceramic body as disclosed herein can include at least one first layer and at least one second layer containing grains, wherein the grains have the same size or substantially the same size between the at least one first layer 100 and the at least one second layer 102.

[0266] The number of grains in contact across the interface may also play a role in the adhesion and strength characteristics of the nonlinear interface 104. The number of grains across the length of the interface is counted to obtain the number of grains per μm. Figure 25 a) shows the number of grains per unit interface length (in μm) of the interface defined by at least one first layer 100 and at least one second layer 102 over 10 images, with a smaller number of grains per micron being preferred. In embodiments, for a multilayer sintered ceramic body comprising YAG as at least one first layer 100 and a second layer having approximately 16% by volume zirconium oxide in an alumina dielectric, the number of grains per micron comprises 0.2 to 0.8 grains / μm, preferably 0.3 to 0.6 grains / μm, preferably 0.4 to 0.55 grains / μm, and preferably an average of approximately 0.5 grains per μm. Figure 25b) depicts the ratio of the interface length (also defined as C, the length of the curve / interface) in the disclosed image area to the linear measurement L (the linear distance between the endpoints of C), which is approximately 54 μm in 10 SEM images, and is defined herein as tortuosity T. As measured using SEM and image processing methods, the nonlinear interface 104 can have a tortuosity (T) of greater than 1.02 to 3, preferably 1.1 to 3, preferably 1.2 to 3, preferably 1.3 to 3, preferably 1.3 to 2.7, and preferably an average tortuosity of approximately 1.7. A higher ratio of interface length C to linear interface length L (or tortuosity, T) is preferred to increase the adhesion strength between the at least one first layer 100 and the at least one second layer 102.

[0267] As described, the nonlinear interface 104 can provide enhanced adhesion strength between the at least one first layer 100 and the at least one second layer 102. This improved adhesion strength can be achieved through increased interface length, increased distance from the interface line, and an interlocking effect between the at least one first layer 100 and the at least one second layer 102 as measured by the tortuosity T.

[0268] Now refer to Figure 26 a) and Figure 26 b) shows an SEM micrograph of the microstructure of the at least one third layer 103. In embodiments, the at least one third layer 103 comprises multiple phases of a ceramic material comprising YAG, alumina, and at least one of unstabilized zirconia, partially stabilized zirconia, and stabilized zirconia. The multi-phase structure of the at least one third layer 103 can provide toughening via an interface between at least two phases, which can facilitate preferential crack propagation along an increased distance of the interface. Figure 26 a) and Figure 26 Depicted in b) are large regions comprising YAG and ZTA (zirconia toughened alumina), each constituting approximately 50 area % as measured using SEM images and ImageJ software.

[0269] Preferably, the disclosed CTE matching between the at least one first layer, the at least one second layer, and the at least one third layer is provided within a temperature range of ambient temperature (or at least from 200° C. as depicted in the accompanying drawings) to about 1700° C. (or at least to 1400° C. as depicted in the accompanying drawings) according to the methods disclosed herein. Selecting materials that provide the disclosed CTE difference for the respective at least one first layer, at least one second layer, and at least one third layer can reduce interfacial stress at the nonlinear interface 104 and the second interface 105, thereby improving adhesion and strength between the at least one first layer 100, the at least one second layer 102, and the at least one third layer 103.

[0270] To form a plasma processing chamber component from the disclosed multilayer sintered ceramic body, the multilayer sintered ceramic body may be subjected to machining, drilling, surface grinding, lapping, polishing, and other processes as needed to form a multilayer sintered component having desired through-holes, surface finishes, and dimensional tolerances according to the component design, such as Figure 27 Schematically depicted in . Figure 27 Exemplary embodiments of multilayer sintered ceramic bodies and multilayer sintered ceramic components made therefrom are shown. Through holes 112 may be formed through at least one first layer 100, at least one second layer 102, and at least one third layer 103 by any number of machining, grinding, and / or drilling processes known to those skilled in the art. A multilayer sintered ceramic component formed from a sintered body as disclosed herein may have any number of through holes 112. Figure 27 a) Figure 27 b) and Figure 27 c), the through hole 112 may include a sidewall 110, wherein the sidewall 110 comprises at least a portion of a crystalline phase of a ceramic material selected from the group consisting of YAG, magnesium aluminate spinel, and yttria and zirconia, wherein the zirconia is present in an amount of not less than 10 mol% and not more than 25 mol%. In some embodiments, the thickness of the at least one second layer 102 is maximized, and the thickness of the at least one first layer 100 and / or the at least one third layer 103 is minimized, each reaching a range of approximately 0.5 mm to 3 mm, preferably 0.5 mm to 1.5 mm. By maximizing the thickness of the at least one second layer 102, corrosion resistance and machinability are provided, in addition to the preferred characteristics of high mechanical strength, high thermal conductivity, high dielectric constant, and low dielectric loss. The at least one second layer 102 formed within the disclosed composition range can provide the aforementioned preferred characteristics required for high-frequency chamber applications. The combination of high strength, corrosion resistance, low dielectric loss, and thermal conductivity of the multilayer sintered ceramic body disclosed herein makes the multilayer sintered ceramic body 98 particularly suitable as a material for manufacturing dielectric windows or RF windows and many other components used in semiconductor plasma processing chambers. These include windows, covers, dielectric windows, RF windows, rings, focus rings, process rings, deposition rings, nozzles, injectors, gas injectors, showerheads, gas distribution plates, diffusers, ion suppressor elements, chucks, electrostatic wafer chucks (ESCs), and pucks.

[0271] However, these necessary grinding and polishing processes always produce defects such as cracks and / or micro cracks (those cracks that are not easily visible to the naked eye) or subsurface defects in the sintered ceramic parts. Figure 6The depicted plasma-facing surface 106 of the at least one first layer 100 minimizes the release of particles into the chamber, preferably minimizing the generation of surface defects and / or subsurface defects during machining. These surface defects and / or subsurface defects can cause micro-cracks on the plasma-facing surface 106 of the first layer 100 that are not readily apparent, which can then cause subsequent release of particles from the plasma-facing surface 106 of the at least one first layer 100 into the plasma processing chamber. Additionally, depending on the relationship between the material type itself (in this case, a brittle, non-metallic ceramic), the crack or defect size (caused by machining), and the applied stress (remaining after machining, and / or due to CTE differences between the layers, and / or arising during use as a sintered ceramic component), the presence of defects on a large scale in the second layer 102 can result in fracture of the sintered body at a strength less than typical for that material. This relationship between material, crack size and stress is based on fracture mechanics as reported by AAGriffith in "The phenomenon of rupture and flow in solids", Phil. Trans. Roy. Soc. London, Vol. 221, Nos. 582-593, January 1, 1921.

[0272] Residual stresses remaining in the sintered body can be caused by CTE differences between the layers, which can develop during the heating, sintering, annealing, and cooling steps used to form the multilayer sintered ceramic bodies herein. Therefore, it is preferred to minimize these internal stresses caused by CTE differences in the subject materials by providing as layers those materials that are CTE matched (within the disclosed ranges) over a temperature range from ambient temperature to the sintering and annealing temperatures disclosed herein, from ambient temperature (or at least from 200° C. as shown in the accompanying drawings) to about 1700° C. (or at least to about 1400° C. as shown in the accompanying drawings).

[0273] If the CTE difference between any one of the at least one first layer 100, the at least one second layer 102 and / or the at least one third layer 103 of the multilayer sintered ceramic body is greater than 0.75×10 -6 / °C, greater stress caused by the CTE mismatch may be exerted on the at least one first layer during machining or drilling steps and may result in surface or subsurface damage in the form of microcracks in the at least one first layer 100. This damage to the at least one first layer may result in spalling and / or increased erosion of the layer, as well as subsequent release of particles from the plasma-facing surface 106 into the plasma processing chamber during use. Therefore, in order to form a multi-layer sintered ceramic body having high strength, sufficient processability, and minimal surface damage to the at least one first layer during machining, the CTE difference between the at least one first layer 100, the at least one second layer 102, and the at least one third layer 103 of the multi-layer sintered ceramic body is preferably within the disclosed ranges, and preferably the CTEs are matched as closely as possible, including a value of zero (wherein there is essentially no difference in CTE as measured according to the disclosed method over a temperature range from ambient temperature (or about 200°C as depicted in the figures) to about 1700°C). As used herein, the term "CTE matching" means that the corresponding CTE values ​​differ (in absolute value) by 0 to 0.75×10 -6 and a smaller combination of at least one first layer 100 , at least one third layer 103 , and at least one second layer 102 .

[0274] Thus, in embodiments, preferred are those materials selected for the first, second, and third layers wherein the absolute value of the difference in coefficient of thermal expansion (CTE) of the first, second, and third layers as measured in accordance with ASTM E228-17 over a temperature range of 25°C to 1700°C or over a temperature range of 200°C to 1400°C is in the range of about 0 to less than 0.75×10-6 / °C, preferably 0 to 0.75×10-6 / °C. -6 / °C, preferably 0 to 0.6×10 -6 / °C, preferably 0 to 0.5×10 -6 / °C, preferably 0 to 0.45×10 -6 / °C, preferably 0 to 0.4×10 -6 / °C, preferably 0 to 0.35×10 -6 / °C, preferably 0 to 0.3×10 -6 / °C, preferably 0 to 0.25×10 -6 / °C, preferably 0 to 0.2×10 -6 / °C, preferably 0 to 0.15×10 -6 / °C, preferably 0 to 0.1×10 -6 / °C, preferably 0 to 0.08×10 -6 / °C, preferably 0 to 0.06×10 -6 / °C, preferably 0 to 0.04×10 -6 / °C, preferably 0 to 0.02×10-6 / °C, and preferably 0 to 0.01×10-6 / °C.

[0275] In embodiments where the CTE of each of the first, second, and third layers do not cross each other within the disclosed temperature range (i.e., the absolute value of the CTE difference is non-zero within the temperature range), the absolute value of the difference in coefficient of thermal expansion (CTE) of the first, second, and third layers may be about 0.003×10 -6 / ℃ to less than 0.75×10 -6 / ℃, preferably 0.003×10 -6 / ℃ to 0.7×10 -6 / ℃, preferably 0.003×10 -6 / ℃ to 0.6×10 -6 / ℃, preferably 0.003×10 -6 / °C to 0.5×10 -6 / ℃, preferably 0.003×10 -6 / °C to 0.45×10 -6 / ℃, preferably 0.003×10 -6 / ℃ to 0.4×10 -6 / ℃, preferably 0.003×10 -6 / °C to 0.35×10 -6 / ℃, preferably 0.003×10 -6 / ℃ to 0.3×10 -6 / ℃, preferably 0.003×10 -6 / ℃ to 0.25×10 -6 / ℃, preferably 0.003×10 -6 / ℃ to 0.2×10 -6 / ℃, preferably 0.003×10 -6 / °C to 0.15×10 -6 / ℃, preferably 0.003×10 -6 / °C to 0.1×10 -6 / ℃, preferably 0.003×10 -6 / ℃ to 0.08×10 -6 / ℃, preferably 0.003×10 -6 / ℃ to 0.06×10 -6 / ℃, preferably 0.003×10 -6 / ℃ to 0.04×10 -6 / ℃, preferably 0.003×10 -6 / ℃ to 0.02×10 -6 / °C, and preferably 0.003×10-6 / °C to 0.01×10 -6 / ℃.

[0276] The disclosed ranges of absolute values ​​of the differences in the coefficients of thermal expansion between the at least one first layer, the at least one second layer, and the at least one third layer are preferably maintained over a temperature range according to the methods disclosed herein. The desired range of absolute values ​​of the differences in the coefficients of thermal expansion between the first layer, the second layer, and the third layer is preferably maintained over a temperature range from ambient temperature (or at least from 200° C. as depicted in the accompanying drawings) to about 1700° C. (or at least to about 1400° C. as depicted in the accompanying drawings), preferably 200° C. to 1400° C., preferably over a sintering temperature range of 1000° C. to 1700° C. and / or an annealing temperature range of 900° C. to 1800° C.

[0277] The use of CTE-matched multilayer sintered ceramic bodies as disclosed herein can reduce stress on the at least one first layer 100 (thereby reducing the likelihood of particle generation in the plasma processing chamber) and improve machinability (through reduction of subsurface and / or surface damage) by providing a symmetrically balanced, matched CTE of the at least one third layer 103 on either side of the at least one second layer 102. In addition, the composition of the at least one second layer 102 can be selected to match the CTE of the at least one first layer 100 and / or the at least one third layer 103 within the disclosed ranges.

[0278] This reduced stress between and within the layers can reduce the effects of surface and subsurface damage during machining, thereby reducing particle generation from the plasma-facing surface 106 of the at least one first layer 100, while improving the overall strength and machinability of the multilayer ceramic sintered bodies (and parts made therefrom) as disclosed herein.

[0279] When the absolute values ​​of the CTE between any of these layers vary within these ranges, the pressure-assisted method as disclosed herein can be used to form multilayer sintered ceramic bodies, especially large (>100 mm) sized multilayer sintered ceramic bodies, having high strength, improved machinability, and reduced surface and subsurface defects.

[0280] Equipment / Spark Plasma Sintering Tools

[0281] The apparatus for preparing the multilayer sintered ceramic body disclosed herein is preferably a spark plasma sintering (SPS) tool comprising: a die comprising a sidewall comprising an inner wall and an outer wall, wherein the inner wall has a diameter defining an interior volume capable of receiving at least one ceramic powder (or at least one powder mixture, as the case may be); and an upper punch and a lower punch operably coupled to the die, wherein each of the upper punch and the lower punch has an outer wall defining a diameter that is smaller than a diameter of the inner wall of the die, whereby when at least one of the upper punch and the lower punch moves within the interior volume of the die, a gap is created between each of the upper punch and the lower punch and the inner wall of the die, wherein the gap is 10 μm to 100 μm wide and the at least one powder mixture has a diameter of 1 μm as measured according to ASTM C1274. 2 / g to 10m 2 / g of specific surface area (SSA).

[0282] like Figure 28 As depicted, the pressure-assisted sintering process (and in preferred embodiments, pressure and current-assisted sintering processes, such as SPS) as disclosed herein provides for the preparation of a monolithic multilayer sintered ceramic body 98 from at least three layers of a powder mixture (powder compact) disposed in a tool set without the use of dopants and / or sintering aids. Figure 28 100a corresponding to at least one first layer 100, 102a corresponding to at least one second layer 102, and 103a corresponding to at least one third layer 103, thereby forming a powder compact) (when sintered in situ) to form an integral multi-layer sintered body 98, after which these layers are formed into at least one first layer 100, at least one second layer 102, and at least one third layer 103 of the sintered body, respectively (rather than forming a film, tape, or green body as is common in the art). In some embodiments, the order of deposition of the at least one first powder mixture and the third powder mixture may be reversed. In embodiments, at least one of the powder mixtures may be calcined, while in other embodiments, all of the powder mixtures may be calcined. Figure 1 and Figure 2 In contrast, the pressure-assisted method produces a high-density, monolithic, multilayer sintered ceramic body without the need to match the sintering rate of the pressureless method as known to those skilled in the art. The absolute value of the CTE difference between the at least one first layer 100, the at least one second layer 102, and the at least one third layer 103 of the multilayer sintered body is preferably within the ranges disclosed herein to avoid cracking and fracture caused by CTE mismatch outside the disclosed ranges (which may be experienced during sintering and during other thermal excursions (such as annealing, etc.)). Figure 4 Depicted.

[0283] Figure 29An SPS tool 1 is depicted having a simplified die / punch arrangement for sintering ceramic powders and / or powder mixtures. Typically, the die / punch arrangement is within a vacuum chamber (not shown), as will be appreciated by one of ordinary skill in the art. Figure 29 The spark plasma sintering tool 1 comprises a mould system 2 comprising a side wall comprising an inner wall 8 having a diameter defining an inner volume capable of receiving a ceramic powder or powder mixture 5 .

[0284] Still refer to Figure 29 The spark plasma sintering tool 1 includes an upper punch 4 and a lower punch 4' operably connected to a mold system 2, wherein each of the upper punch 4 and the lower punch 4' has an outer wall 11, and the diameter defined by the outer wall is smaller than the diameter of the inner wall 8 of the mold system 2, thereby when at least one of the upper punch 4 and the lower punch 4' moves within the internal volume of the mold system 2, a gap 3 is generated between each of the upper punch 4 and the lower punch 4' and the inner wall 8 of the mold system 2.

[0285] The die system 2 and the upper punch 4 and lower punch 4 'can comprise at least one graphite material. In certain embodiments, the graphite material disclosed herein can comprise at least one isotropic graphite material. In other embodiments, the graphite material disclosed herein can comprise at least one reinforced graphite material, such as a carbon-carbon composite material, and a graphite material of a laminate of fibers, particles or sheets or meshes or other conductive materials such as carbon included in a matrix of an isotropic graphite material. In other embodiments, the die and the upper punch and lower punch can comprise a combination of these isotropic and reinforced graphite materials.

[0286] The graphite material used for some or all of the components of the tooling, such as the die 6 and punches 4 and 4', may comprise a porous graphite material exhibiting a porosity of about 5% to about 20%, about 5% to about 17%, about 5% to about 13%, about 5% to about 10%, 5% to about 8%, about 8% to about 20%, about 12% to 20%, about 15% to about 20%, about 11% to about 20%, about 5% to 15%, 6% to about 13%, and preferably about 7% to about 12%.

[0287] Preferably, the graphite material has an average pore size (pore diameter) of 0.4 μm to 5.0 μm, preferably 1.0 μm to 4.0 μm, and includes pores with a surface pore size of at most 30 μm, preferably at most 20 μm, preferably at most 10 μm. More preferably, pores with a surface pore size of 10 μm to 30 μm may be present.

[0288] The average grain size of the graphite material for tools as disclosed herein may be <0.05 mm, preferably <0.04 mm, preferably <0.03 mm, preferably <0.028 mm, preferably <0.025 mm, preferably <0.02 mm, preferably <0.018 mm, preferably <0.015 mm, and preferably <0.010 mm.

[0289] The average grain size of the graphite material for tools as disclosed herein may be >0.001 mm, preferably >0.003 mm, preferably >0.006 mm, preferably >0.008 mm, preferably >0.010 mm, preferably >0.012 mm, preferably >0.014 mm, preferably >0.020 mm, preferably >0.025 mm, and preferably >0.030 mm.

[0290] The density of the graphite material used for the tool as disclosed herein may be ≥ 1.45 g / cm 3 , preferably ≥1.50g / cm 3 , preferably ≥1.55g / cm 3 , preferably ≥1.60g / cm 3 , preferably ≥1.65g / cm 3 , preferably ≥1.70g / cm 3 , and preferably ≥1.75g / cm 3 .

[0291] The density of the graphite material used for the tool as disclosed herein can be < 2.0g / cm 3 , preferably 1.90g / cm 3 , preferably < 1.85g / cm 3 And preferably < 1.80g / cm 3 .

[0292] In an embodiment, the coefficient of thermal expansion (CTE) of the graphite material in the temperature range of about 400°C to about 1400°C is ≥3.3×10 -6 / ℃, ≥3.5×10 -6 / ℃,≥3.7×10 -6 / ℃,≥4.0×10 -6 / ℃,≥4.2×10 -6 / ℃,≥4.4×10 -6 / ℃,≥4.6×10 -6 / ℃,≥4.8×10 -6 / ℃.

[0293] In an embodiment, the coefficient of thermal expansion (CTE) of the graphite material in the temperature range from about 400°C to 1400°C may be < 7.2×10 -6 / ℃, preferably < 7.0×10 -6 / ℃, preferably < 6.0×10 -6 / ℃, preferably < 5.0×10 -6 / ℃, preferably < 4.8×10 -6 / ℃, and preferably < 4.6×10 -6 / ℃.

[0294] Table 9 lists properties of exemplary graphite materials as disclosed herein.

[0295] Table 9

[0296] nature scope Density (g / cc) 1.45 to 2.0 Average grain size (μm) 1 to <50 Resistivity (Ohm-cm) 0.001 to 0.003 Flexural strength (MPa) 40-160 Compression strength (MPa) 80-260 <![CDATA[CTE(x10 -6 / C), at 400°C to 1400°C]]> 3.3 to 7 Porosity% 5 to 20 Average pore size (μm) 0.4 to 5 Thermal K (W / mK) 40-130 Shore hardness (HSD) 55 to 59 Tensile strength (MPa) 25 to 30 Elastic modulus (GPa) 9 to 11 Impurities / ash (ppm) 3 to 500

[0297] The mold system 2 comprises a mold 6 and optionally but preferably at least one conductive foil 7 located on the inner wall of the mold, such as Figure 25 a) to Figure 25 c). The number of conductive foils on the inner wall of the die is not limited, and 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 conductive foils can be provided as circumferential spacers between the die 6 and each of the upper punch 4 and the lower punch 4', whereby the inner wall 8 of the die system 2 (including at least one conductive foil, if present) and the outer wall 11 of each of the upper punch and the lower punch define the gap 3. The at least one conductive foil 7 can comprise graphite, niobium, nickel, molybdenum, platinum, and other ductile conductive materials, as well as combinations thereof, which are stable within the temperature range according to the method as disclosed herein.

[0298] In certain embodiments, the conductive foil may include a flexible and compressible graphite foil as disclosed herein having one or more of the following properties:

[0299] a carbon content greater than 99% by weight, preferably greater than 99.2% by weight, more preferably greater than 99.4% by weight, more preferably greater than 99.6% by weight, more preferably greater than 99.8% by weight, more preferably greater than 99.9% by weight, more preferably greater than 99.99% by weight, and more preferably greater than 99.999% by weight;

[0300] Impurities are less than 500 ppm, preferably less than 400 ppm, more preferably less than 300 ppm, more preferably less than 200 ppm,

[0301] More preferably less than 100 ppm, more preferably less than 50 ppm, more preferably less than 10 ppm, more preferably less than 5 ppm,

[0302] and more preferably less than 3 ppm;

[0303] The tensile strength of the graphite foil is in the range of 4.0 MPa to 6.0 MPa, preferably 4.2 MPa to 5.8 MPa, more preferably 4.4 MPa or 5.6 MPa; and / or

[0304] The bulk density of the graphite foil is preferably in the range of 1.0 g / cc to 1.2 g / cc, preferably 1.02 g / cc to 1.18 g / cc,

[0305] More preferably, it is 1.04 g / cc to 1.16 g / cc, and more preferably, it is 1.06 g / cc to 1.16 g / cc.

[0306] In embodiments, the at least one foil generally comprises graphite.In certain embodiments, the at least one foil as part of the die system may include a circumferential spacer between a surface of the die and each of the upper and lower punches.

[0307] Graphite foil can improve the temperature distribution of the powder during sintering.Table 10 lists properties of exemplary graphite foil according to embodiments as disclosed herein.

[0308] Table 10

[0309] Thickness (mm) 0.030 to 0.260 <![CDATA[Density (Mg / m 3 )]]> 0.5 to 2 Tensile strength (MPa) 4.9-6.3 Resistivity (μOhm-m; 25℃) (parallel to the surface) 5 to 10 Resistivity (μOhm-m; 25℃) (perpendicular to the surface) 900 to 1100 CTE (×10-6 / °C; parallel to the surface) at 350°C to 500°C 5 to 5.5 CTE (perpendicular to the surface) at 350°C to 500°C <![CDATA[2×10 -4 ]]> Compressibility (%) 40-50 Recovery rate (%) 10 to 20 Thermal conductivity (W / mK, at 25°C; parallel to the surface) 175 to 225 Thermal conductivity (W / mK, at 25°C; perpendicular to the surface) ～5 Impurities / ash (weight %) <0.5

[0310] Now refer to Figure 30a), Figure 25 30 b) and FIG30 c), show the SPS tool group of the embodiment with graphite foil arrangement.At least one ceramic powder (or powder mixture) 5 is arranged between at least one of the upper punch 4 and the lower punch 4 ', and the gap 3 is shown between the outer wall 11 of each of the upper punch and the lower punch and the inner wall 8 of the mold system 2. Figure 30 a), Figure 30 b) and Figure 30 c) respectively depict 1 to 3 layers of conductive foil 7 and the mold 6 as part of the mold system 2. Therefore, the gap extends from the inner wall 8 of the mold system 2 to the outer wall 11 of each of the upper punch and the lower punch. The gap distance is arranged so that the powder can be degassed before and / or during heating and sintering, while also maintaining ohmic contact between the punch and the die, to improve the temperature distribution on the ceramic powder or powder mixture during heating and sintering.

[0311] The thickness of the graphite foil 7 can be, for example, 0.025 mm to 0.260 mm, preferably 0.025 mm to 0.200 mm, preferably 0.025 mm to 0.175 mm, preferably 0.025 mm to 0.150 mm, preferably 0.025 mm to 0.125 mm, preferably 0.035 mm to 0.200 mm, preferably 0.045 mm to 0.200 mm, and preferably 0.055 mm to 0.200 mm.

[0312] The distance of the gap 3 is measured from the inwardly facing surface of the foil 7 closest to the upper punch 4 and the lower punch 4' to the outer wall 11 of each of the upper punch and the lower punch. The preferred range of the distance of the gap 3 is preferably 10 μm to 100 μm, 10 μm to 70 μm, preferably 10 μm to 60 μm, preferably 10 μm to 50 μm, preferably 30 μm to 70 μm, preferably 20 μm to 60 μm, and preferably 30 μm to 60 μm.

[0313] Furthermore, the width of the gap 3 between the inner wall 8 of the mold system 2 and the outer wall 11 of each of the upper punch 4 and the lower punch 4' can be determined by one skilled in the art to, on the one hand, adequately promote powder degassing during the preheating, heating, and sintering processes, and, on the other hand, achieve sufficient electrical contact for Joule or resistive heating, thereby enabling sintering. If the distance of the gap 3 is less than 10 μm, the force required to move at least one of the upper and lower punches within the internal volume of the mold system and thereby assemble the tool set may cause damage to the tool set. Furthermore, a gap 3 less than 10 μm may not allow adsorbed gases, organic matter, moisture, etc. within the powder 5 to escape, which would increase processing time during the manufacturing process and may result in residual porosity in the resulting sintered ceramic body, thereby reducing density. If the width of the gap 3 is greater than 70 μm when sintering the ceramic powder or powder mixture, localized overheating may occur, thereby generating thermal gradients within the tool set during sintering. Therefore, in order to form a multilayer sintered ceramic body of large size (maximum dimension up to about 625 mm) (such as the multilayer sintered ceramic body disclosed herein), a gap of 10 μm to 100 μm is preferred. Therefore, in some embodiments, when sintering the sintered ceramic powder or powder mixture, the distance of the gap 3 between the inner wall 8 of the mold system 2 and the outer wall 11 of each of the upper punch and the lower punch is preferably 10 μm to 100 μm, 10 μm to 70 μm, preferably 10 μm to 60 μm, preferably 10 μm to 50 μm, preferably 10 μm to 40 μm, preferably 20 μm to 70 μm, preferably 30 μm to 70 μm, preferably 40 μm to 70 μm, preferably 50 μm to 70 μm, preferably 30 μm to 60 μm.

[0314] These thermal gradients can result in low overall or bulk density and high density variations as well as sintered ceramic bodies that are brittle and prone to cracking. Therefore, when sintering ceramic powders or powder mixtures as disclosed herein, the distance of the gap 3 between the inner wall 8 of the mold system 2 and the outer wall 11 of each of the upper and lower punches is 10 μm to 100 μm, 10 μm to 70 μm, preferably 10 μm to 60 μm, preferably 10 μm to 40 μm, preferably 20 μm to 70 μm, preferably 40 μm to 70 μm, preferably 50 μm to 70 μm, preferably 30 μm to 70 μm, preferably 40 μm to 60 μm. Without being bound by a particular theory, it is believed that during sintering, the gap distance between the inner wall 8 of the mold system 2 and the outer wall 11 of each of the upper and lower punches facilitates powder degassing of organic matter, moisture, adsorbed molecules, etc. during the sintering process. This results in a sintered ceramic body (such as the multilayer body disclosed herein) having large dimensions and having high density and low volume porosity and improved mechanical properties, so that the body can be easily handled and machined into chamber components of predetermined forms without breakage. The multilayer sintered ceramic body prepared as disclosed herein can have dimensions of 100 mm to about 625 mm relative to the largest dimension of the multilayer sintered ceramic body 98.

[0315] In practice, the upper punch 4 and the lower punch 4' are not always perfectly aligned around the central axis. Figures 31a) and 31b) are plan views of the tool set 1 showing the alignment of the upper punch 4 and the lower punch 4', the gap 3, any number of conductive foils 7, and the mold system 2 around the central axis 9. In the embodiment depicted in Figure 31a), the gap can be axisymmetric about the central axis 9. In other embodiments depicted in Figure 31b), the gap can be asymmetric about the central axis 9. In the depicted axisymmetric and asymmetric embodiments, the gap 3 can extend between 10 μm and 100 μm when the ceramic powder or powder mixture is sintered to form a multilayer sintered ceramic body as disclosed herein.

[0316] Gap asymmetry performance can be measured by performing absolute radial CTE deviation analysis over a range of temperatures. For example, Figure 32 Shown are the radial deviations in the average CTE of two isotropic graphite materials (A and B) used as the punch and die of the apparatus disclosed herein at 1200°C. Figure 32 It is shown that for materials to successfully maintain the desired gap over a large temperature range, the maximum change in radial deviation in the xy plane cannot be >0.3×10-6, from, for example, room temperature to 2000° C. Material B exhibits unacceptable CTE expansion in the xy plane, while material A exhibits acceptable CTE expansion over the entire temperature range.

[0317] The advantages of the particular tool set design used in accordance with one embodiment can produce an overall technical effect of providing very high purity, larger, multi-layer sintered ceramic bodies having a high and uniform density and low volume porosity, thereby reducing the tendency to crack in sintering processes according to the present disclosure, particularly in SPS processes. Thus, all features disclosed with respect to the tool set are also applicable to multi-layer sintered ceramic body products having dimensions greater than 100 mm and up to and including about 625 mm.

[0318] By using a tool set as disclosed herein, it is possible to achieve a more uniform temperature distribution in the ceramic powder or powder mixture 5 to be sintered and to produce sintered ceramic bodies, particularly large-sized sintered ceramic bodies (maximum dimensions exceeding, for example, 100 mm and / or 200 mm, including up to about 625 mm and larger), which have very high density (>98% of the theoretical density of the specified material) and enhanced interlayer adhesion, thereby reducing the tendency to crack. The word "uniform" means that the material or system has essentially the same properties at every point; it is uniform and has no irregularities. Thus, a "uniform temperature distribution" means that the temperature distribution is uniform in space and does not have substantial gradients, i.e., a substantially uniform temperature exists regardless of the position along the ceramic powder or powder mixture 5 in the horizontal xy plane.

[0319] The disclosed tool sets may also include spacer elements, spacers, gaskets, and other tool set components. Typically, such components are made of at least one graphite material having the properties as disclosed herein.

[0320] like Figure 33 As shown, embodiments of the technology disclosed herein can be used as components in a plasma processing system 9500 that can be configured for a semiconductor etching process, also referred to as an "etch processing system." The etch processing system 9500 in embodiments can include a remote plasma region. The remote plasma region can include a remote RF source / matching network 9502, also referred to as a remote plasma source ("RPS").

[0321] The etching process system 9500 may include a vacuum chamber 9550 having a corrosion-resistant chamber liner (not shown), a vacuum source, and a chuck or electrostatic chuck ("ESC") 9509 on which a wafer 50 (also shown as a substrate) is supported. A cover ring or electrode cover 9514, a top shield ring 9512, and a shield ring 9513 surround the wafer 50 and the positioning plate 9509. A top plate / window / lid 9507 forms the upper wall of the vacuum chamber 9550. A showerhead 9517 forms the upper wall of the vacuum chamber 9650 or is mounted below the upper wall. The top plate / window / cover 9507 (which may include an RF window or a dielectric window), gas distribution system 9506, showerhead 9517, cover ring or electrode cover 9514, top shield ring 9512, shield ring 9513, chamber liner (not shown), and chuck or electrostatic chuck (ESC) 9508 and positioning plate 9509 can be made at least in part of embodiments of the multilayer sintered ceramic body as disclosed herein.

[0322] Portions of the surface of the showerhead 9517 may be covered with a shield ring 9712. Portions of the surface of the showerhead 9517, particularly radial sides of the surface of the showerhead 9517, may be covered with a top shield ring 9710. The shield ring 9712, the showerhead 9517, and the top shield ring 9710 may be made, at least in part, of embodiments of a multilayer sintered ceramic body as disclosed herein.

[0323] A remote plasma source 9502 is disposed outside a window 9507 of a chamber 9550 for accommodating a wafer 50 to be processed. The remote plasma region can be fluidically connected to the vacuum chamber 9550 via a gas delivery system 9506. Active plasma can be generated in the chamber 9550 by supplying a processing gas to the chamber 9550 and high-frequency power to the plasma source 9502. Using the active plasma thus generated, a predetermined plasma process is performed on the wafer 50. A planar antenna having a predetermined pattern is commonly used as the high-frequency antenna of the etching processing system 9500.

[0324] like Figure 34As shown, embodiments of the technology disclosed herein can be used as components in a plasma processing system 9600 that can be configured for semiconductor deposition processes, also referred to as a "deposition processing system." The deposition processing system 9600 includes a vacuum chamber 9650, a vacuum source, and a positioning plate 9609 on which a wafer 50 (also represented as a semiconductor substrate) is supported. The processing system can also include a nozzle or injector 9614 that is in fluid communication with a gas delivery system 9616 for supplying process gas to the interior of the vacuum chamber 9650. The top wall 9700 of the chamber 9650 can include a central opening configured to receive a central gas injector (also referred to as a nozzle) 9614. In certain embodiments, the top wall 9700 of the chamber can include an RF or dielectric window configured with a central opening to accommodate the injector 9614. The RF energy source excites the process gas into a plasma state to process the substrate 50. Embodiments of the top wall including the RF or dielectric window 9700, the gas delivery system 9616, and the central gas injector 9614 may be made in whole or in part from embodiments of the multilayer sintered ceramic bodies as disclosed herein.

[0325] The deposition processing system 9600 may also include an electrostatic chuck 9608 designed to support the wafer 50. The chuck 9608 may include a positioning plate 9609 for supporting the wafer 50. A portion of the supporting surface of the positioning plate 9609 may be covered with a deposition ring 9615. Other names for the deposition ring 9615, such as a deposition shield or a deposition ring assembly, are considered synonymous and may be used interchangeably herein. The deposition ring 9615 may be made, in whole or in part, of an embodiment of a multilayer sintered ceramic body as disclosed herein.

[0326] The puck 9609 can be formed in whole or in part from embodiments of a multi-layer sintered ceramic body as disclosed herein and can have chucking electrodes disposed within the puck near a support surface of the puck 9609 to electrostatically hold the wafer 50 when placed on the puck 9609. The chuck 9608 can include a pedestal 9611 having a ring extending to support the puck 9609, and a shaft 9610 disposed between the pedestal and the puck to support the puck above the pedestal such that a gap is formed between the puck 9609 and the pedestal 9610, wherein the shaft 9610 supports the puck near a peripheral edge of the puck 9609. The chuck 9608, the puck 9609, and the deposition ring 9615 can be made in whole or in part from embodiments of a unitary multi-layer sintered ceramic body as disclosed herein.

[0327] Preparation method

[0328] The preparation of multilayer sintered ceramic bodies can be achieved by using pressure-assisted sintering, such as spark plasma sintering (SPS), also known as field-assisted sintering technology (FAST) or direct current sintering (DCS). These DC sintering and related technologies use direct current to heat an electrically conductive mold structure or tool set, thereby heating the material to be sintered. This heating method allows the application of very high heating and cooling rates, thereby enhancing the densification mechanism rather than the diffusion mechanism that promotes grain growth, which can help to prepare ceramic sintered bodies with very fine grain sizes and transfer the inherent properties of the original powder into a nearly or fully dense product. The DC pressure-assisted method as disclosed herein utilizes preferably non-pulsed, continuous direct current to heat the disclosed tool set.

[0329] The preparation of multilayer sintered ceramic bodies as disclosed herein may also be achieved by using a pressure-assisted sintering process such as uniaxial hot pressing, whereby the mold construction or tool set is heated by an externally applied heat source such as induction heating.

[0330] The multilayer sintered ceramic body is prepared according to the following general process steps: a) combining at least two powders selected from the group consisting of yttria, aluminum oxide, magnesium oxide and at least one zirconium oxide (wherein the at least one zirconium oxide is selected from the group consisting of unstabilized zirconium oxide, partially stabilized zirconium oxide and stabilized zirconium oxide) and combinations thereof to prepare a first powder mixture; b) combining aluminum oxide powder with at least one of partially stabilized zirconium oxide powder and stabilized zirconium oxide powder to prepare a second powder mixture; c) combining yttria powder, aluminum oxide powder and at least one of unstabilized zirconium oxide powder, partially stabilized zirconium oxide powder and stabilized zirconium oxide powder to prepare a third powder mixture; d) calcining at least one of the first, second and third powder mixtures by applying heat to raise the temperature of at least one of the first, second and third powder mixtures to a calcining temperature and maintaining the calcining temperature for calcining to form at least one of a first calcined powder mixture, a second calcined powder mixture and a third calcined powder mixture; e) separately placing at least one of the first, second and third powder mixtures in a sintering device. and a plurality of tooling members configured to form at least one layer of a first powder mixture, at least one layer of a second powder mixture, and at least one layer of a third powder mixture within a volume defined by a tooling group equipped with a plurality of tooling members, wherein the tooling group comprises a die, the die comprising a side wall, the side wall comprising an inner wall and an outer wall, wherein the inner wall has a diameter defining an interior volume capable of receiving at least one powder; and an upper punch and a lower punch operably coupled to the die, wherein each of the upper punch and the lower punch has an outer wall defining a diameter that is smaller than a diameter of the inner wall of the die, whereby when the upper punch and the lower punch are engaged, a vacuum condition is generated within the volume. and forming a multilayer sintered ceramic body by pressing and sintering the layers of the first powder mixture, the second powder mixture, and the third powder mixture while heating to a sintering temperature, wherein at least one layer of the first powder mixture forms at least one first layer, at least one layer of the second powder mixture forms at least one second layer, and at least one layer of the third powder mixture forms at least one third layer;and g) reducing the temperature of a multi-layer sintered ceramic body, wherein at least one first layer comprises at least one polycrystalline ceramic material selected from the group consisting of (i) YAG, (ii) magnesium aluminate spinel, and (iii) yttria and zirconia, wherein the zirconia is present in an amount of not less than 10 mol% ZrO2 and not more than 25 mol% ZrO2, preferably not less than 12 mol% and not more than 25 mol% ZrO2, preferably not less than 15 mol% and not more than 25 mol% ZrO2, preferably not less than 18 mol% and not more than 25 mol% ZrO2, preferably not less than 10 mol% and not more than 23 mol% ZrO2, preferably not less than 10 mol% % and not more than 20 mol % ZrO2, preferably not less than 15 mol % and not more than 23 mol % ZrO2 is present (with the balance comprising Y2O3), and the at least one second layer comprises aluminum oxide and zirconium oxide, wherein the zirconium oxide comprises at least one of stabilized zirconium oxide and partially stabilized zirconium oxide, and the at least one third layer comprises at least one selected from the group consisting of yttria, aluminum oxide and zirconium oxide, wherein the zirconium oxide comprises at least one of unstabilized zirconium oxide, stabilized zirconium oxide and partially stabilized zirconium oxide, wherein the at least one second layer is disposed between the at least one first layer and the at least one third layer, wherein the absolute value of the difference in coefficient of thermal expansion (CTE) between any one of the at least one first layer, the at least one second layer and the at least one third layer is 0 to 0.75×10-6 / °C as measured according to ASTM E228-17, wherein the at least one first layer, the at least one second layer and the at least one third layer form an integrally sintered ceramic body. In a preferred embodiment, according to steps a), b) and c), the powder selected from the group consisting of yttrium oxide, aluminum oxide, magnesium oxide and at least one selected from the group consisting of unstabilized zirconium oxide, partially stabilized zirconium oxide and stabilized zirconium oxide each has a particle size as measured according to ASTM C1274 of about 18 m; 2 / g and less, preferably about 1m 2 / g to about 18m 2 Preferably, the first powder mixture, the second powder mixture and the third powder mixture have a total impurity content of 200 ppm and less as measured relative to the mass of the first powder mixture, the second powder mixture and the third powder mixture.

[0331] The at least one second powder mixture comprises aluminum oxide and zirconium oxide, wherein the zirconium oxide comprises at least one of stabilized zirconium oxide and partially stabilized zirconium oxide. The at least one second powder mixture comprises aluminum oxide in an amount of 60% to 92.5% by weight, preferably 75% to 85% by weight, preferably about 77% by weight, relative to the weight of the at least one second powder mixture. The at least one second powder mixture comprises zirconium oxide (to include a stabilizer to form at least one of stabilized zirconium oxide and partially stabilized zirconium oxide) in an amount of 7.5% to 40% by weight, preferably 15% to 25% by weight, preferably about 23% by weight, relative to the weight of the at least one second powder mixture. When sintered, these composition ranges of the at least one second powder mixture correspond to at least one second layer 102 comprising zirconium oxide (when sintered) in an amount of 5% to 30% by volume, preferably 10% to 30% by volume, preferably 15% to 30% by volume, preferably 20% to 30% by volume, preferably 12% to 25% by volume, preferably 15% to 25% by volume, preferably 17% to 25% by volume, preferably 10% to 22% by volume, preferably 10% to 20% by volume, preferably 10% to 17% by volume, preferably 15% to 21%, preferably 16% to 20%, and preferably about 16% by volume, each relative to the volume of the at least one second layer 102. These volumetric amounts of zirconium oxide can be measured using a combination of SEM imaging and ImageJ analysis software according to the methods disclosed herein.

[0332] The at least one third powder mixture comprises at least one member selected from the group consisting of yttria, aluminum oxide, and zirconium oxide, wherein the zirconium oxide comprises at least one member selected from the group consisting of unstabilized zirconium oxide, partially stabilized zirconium oxide, and stabilized zirconium oxide. The at least one third powder mixture comprises yttria in an amount by weight of 1% to 57%, preferably 3% to 57%, preferably 5% to 57%, preferably 1% to 40%, preferably 1% to 30%, preferably 3% to 30%, preferably 5% to 30%, preferably 5% to 15%, and preferably about 6%, relative to the weight of the at least one third powder mixture. The at least one third powder mixture comprises aluminum oxide in an amount by weight of 43% to 92.5%, preferably 65% ​​to 75%, preferably about 73%, relative to the weight of the at least one third powder mixture. The at least one third powder mixture comprises zirconium oxide (including stabilizers, where applicable, to form stabilized zirconium oxide and / or unstabilized zirconium oxide) in an amount by weight of about 0.4% to 40%, preferably 4% to 40%, preferably 15% to 40%, preferably 15% to 25%, preferably about 21%, relative to the weight of the at least one third powder mixture. Upon sintering, these composition ranges of the at least one third powder mixture may correspond to exemplary SEM images of the at least one third layer 103 comprising a multiphase structure of YAG, zirconium oxide, and aluminum oxide, as shown in FIG. Figure 26 a) and Figure 26 b). In a preferred embodiment, the at least one third powder mixture comprises an amount of zirconium oxide for the at least one third layer (when sintered) to comprise ZrO2 (with the balance comprising Y2O3 and Al2O3) in an amount of about 5 vol% to about 30 vol%, preferably 5 vol% to 25 vol%, preferably 5 vol% to 20 vol%, preferably 5 vol% to 16 vol%, preferably 10 vol% to 30 vol%, preferably 15 vol% to 30 vol%, preferably 20 vol% to 30 vol%, and preferably 15 vol% to 20 vol%, each relative to the volume of the at least one third layer 103.

[0333] The following additional steps are optional; h) optionally annealing the multilayer sintered ceramic body by applying heat to raise the temperature of the multilayer sintered ceramic body to an annealing temperature for annealing; i) reducing the temperature of the annealed multilayer sintered ceramic body; and j) machining the multilayer sintered ceramic body or the annealed multilayer sintered ceramic body to form multilayer sintered ceramic parts in the shape of windows, covers, dielectric windows, RF windows, rings, focus rings, process rings, deposition rings, nozzles, injectors, gas injectors, showerheads, gas distribution plates, diffusers, ion suppressor elements, chucks, electrostatic wafer chucks (ESCs), and positioning plates.

[0334] In some embodiments, an optional annealing step may be performed. Optionally, annealing is performed by applying heat to raise the temperature of the multi-layer sintered ceramic body to an annealing temperature, performing the annealing, and reducing the temperature of the sintered and annealed multi-layer sintered ceramic body to ambient temperature by removing the heat source applied to the body and removing the multi-layer sintered ceramic body.

[0335] The above-described features of the corrosion-resistant multilayer sintered ceramic body according to one embodiment are achieved in part by adjusting the purity and specific surface area (SSA) of the first powder mixture, the second powder mixture, and the third powder mixture, the pressure of the first mixture, the second mixture, and the third mixture, the temperature of the first powder mixture, the second powder mixture, and the third powder mixture, the sintering duration of the first powder mixture, the second powder mixture, and the third powder mixture, the temperature of the multilayer sintered ceramic body during an optional annealing step, and the duration of the optional annealing step.

[0336] A method for preparing a multilayer sintered ceramic body is disclosed, the method comprising the steps of: a) combining at least two powders selected from the group consisting of yttria, aluminum oxide, magnesium oxide, and at least one zirconium oxide (the at least one zirconium oxide selected from the group consisting of unstabilized zirconium oxide, partially stabilized zirconium oxide, and stabilized zirconium oxide), and combinations thereof, to prepare a first powder mixture; b) combining aluminum oxide powder with at least one of partially stabilized zirconium oxide powder and stabilized zirconium oxide powder to prepare a second powder mixture; c) combining yttria powder, aluminum oxide powder, and at least one of unstabilized zirconium oxide powder, partially stabilized zirconium oxide powder, and stabilized zirconium oxide powder to prepare a third powder mixture; d) calcining at least one of the first, second, and third powder mixtures by applying heat to raise the temperature of the first, second, and third powder mixtures to a calcining temperature and maintaining the calcining temperature for calcining, thereby forming at least one of a first calcined powder mixture, a second calcined powder mixture, and a third calcined powder mixture; and e) separately placing the first, second, and third powder mixtures in a sintering process limited by a tool assembly of a sintering apparatus. The tool set comprises a die, the die comprising a side wall, the side wall comprising an inner wall and an outer wall, wherein the inner wall has a diameter defining an interior volume capable of receiving at least one powder; and an upper punch and a lower punch operably coupled to the die, wherein each of the upper punch and the lower punch has an outer wall defining a diameter that is smaller than a diameter of the inner wall of the die, whereby when at least one of the upper punch and the lower punch is pressed defining a gap between each of the upper punch and the lower punch and an inner wall of the die when moving within the interior volume of the die, wherein the gap is 10 μm to 100 μm wide; f) applying pressure to and sintering the layers of at least one of the first powder mixture, the second powder mixture, and the third powder mixture while heating to a sintering temperature to form a multilayer sintered ceramic body, wherein the at least one layer of the first powder mixture forms at least one first layer, the at least one layer of the second powder mixture forms at least one second layer, and the at least one layer of the third powder mixture forms at least one third layer when sintered;and g) reducing the temperature of the multi-layer sintered ceramic body, wherein the first layer comprises at least one crystalline phase of a ceramic material selected from the group consisting of (i) YAG, (ii) magnesium aluminate spinel, and (iii) yttria and zirconium oxide, wherein the zirconium oxide is present in an amount of not less than 10 mol% ZrO2 and not more than 25 mol% ZrO2, preferably not less than 12 mol% and not more than 25 mol% ZrO2, preferably not less than 15 mol% and not more than 25 mol% ZrO2, preferably not less than 18 mol% and not more than 25 mol% ZrO2, preferably not less than 10 mol% and not more than 23 mol% ZrO2, preferably not less than 10 mol% and not more than 20 mol% ZrO2, and preferably not less than 15 mol% and not more than 23 mol% ZrO2. The at least one second layer comprises aluminum oxide and zirconium oxide, wherein the zirconium oxide comprises at least one of unstabilized zirconium oxide, stabilized zirconium oxide, and partially stabilized zirconium oxide, wherein the at least one second layer is disposed between the at least one first layer and the at least one third layer, wherein the absolute value of the difference in coefficient of thermal expansion (CTE) between any of the at least one first layer, the at least one second layer, and the at least one third layer, as measured in accordance with ASTM E228-17, is between 0 and 0.75×10-6 / °C, wherein the at least one first layer, the at least one second layer, and the at least one third layer form a monolithic sintered ceramic body. In a preferred embodiment, the powder selected from the group consisting of yttrium oxide, aluminum oxide, and magnesium oxide, and the at least one selected from the group consisting of unstabilized zirconium oxide, partially stabilized zirconium oxide, and stabilized zirconium oxide each have a particle diameter of approximately 18 μm as measured in accordance with ASTM C1274. 2 / g and less, preferably about 1m 2 / g to about 18m 2 In another preferred embodiment, at least one of the first powder mixture, the second powder mixture, and the third powder mixture (or the calcined powder mixture, as the case may be) each has a specific surface area of ​​about 18 m / g as measured according to ASTM C1274. 2 / g and smaller, preferably 1m 2 / g to 18m 2 Preferably, the first powder mixture, the second powder mixture and the third powder mixture have a total impurity content of 200 ppm and less as measured relative to the mass of the first powder mixture, the second powder mixture and the third powder mixture.

[0337] The following additional steps are optional: h) optionally annealing the multilayer sintered ceramic body by applying heat to raise the temperature of the multilayer sintered ceramic body to an annealing temperature for annealing; i) reducing the temperature of the annealed multilayer sintered ceramic body; and j) machining the multilayer sintered ceramic body or the annealed multilayer sintered ceramic body to form a multilayer sintered ceramic component in the shape of a window, lid, dielectric window, RF window, ring, focus ring, process ring, deposition ring, nozzle, injector, gas injector, showerhead, gas distribution plate, diffuser, ion suppressor element, chuck, electrostatic wafer chuck (ESC), and positioning plate for use in a plasma processing chamber.

[0338] Step a) of the method disclosed herein comprises combining at least two powders selected from the group consisting of yttria, alumina, magnesium oxide, and zirconium oxide (wherein zirconium oxide is selected from at least one of unstabilized zirconium oxide, partially stabilized zirconium oxide, and stabilized zirconium oxide) to prepare a first powder mixture; combining and mixing the starting powder materials comprising the first powder mixture in proportions such that upon sintering, the at least one first powder mixture forms at least one first layer comprising at least one crystalline phase of a ceramic material comprising YAG, magnesium aluminate spinel, or comprising yttria and zirconium oxide, wherein the zirconium oxide is present in an amount of not less than 10 mol% ZrO2 and not more than 25 mol% ZrO2 and the balance comprising Y2O3. The powder selected for forming the at least one first powder mixture is preferably a commercially available powder of high purity (>99.99%). However, other oxide powders, such as those produced by chemical synthesis processes and related methods, may be used as long as the high purity requirements are met.

[0339] The particle size of the starting powder, powder mixture, and calcined powder mixture can be measured using a Horiba Model LA-960 Laser Scattering Particle Size Distribution Analyzer capable of measuring particle sizes from 10 nm to 5 mm. The specific surface area (SSA) of the starting powder, powder mixture, and calcined powder mixture can be measured using a Horiba BET Surface Area Analyzer Model SA-9601 capable of measuring particle sizes from 0.01 nm to 5 mm. 2 / g to 2000m 2 / g of specific surface area with an accuracy of 10% and lower for most samples. The purity of the starting powder, powder mixture and calcined powder mixture can be measured using ICP-MS measurements using an Agilent 7900 ICP-MS model G8403, which is capable of analyzing lighter elements (such as Sc and smaller atomic numbers) to about 1.4 ppm and heavier elements (such as atomic numbers higher than Sc) to about 0.14 ppm. Purity is reported herein as a percentage relative to 100% purity, which means that 100% purity represents a material containing only the expected components without impurities, dopants, sintering aids, etc. Impurity content is reported herein in ppm relative to the total mass of the material being evaluated. Silica is not disclosed in the purity and impurity reports and can be measured in an amount of about 14 ppm using the ICP-MS method as disclosed herein.

[0340] As used herein, d50 is defined as the median and represents the value at which half of the particle size distribution lies above this point and half lies below this point. Similarly, 90% of the distribution is below d90, and 10% of the distribution is below d10.

[0341] The starting powders of yttrium oxide, zirconium oxide, magnesium oxide and aluminum oxide as disclosed herein are preferably crystalline and therefore have long range crystal order. Any or all of the starting powders of yttrium oxide, zirconium oxide, magnesium oxide and aluminum oxide may be sieved, tumbled, blended, ground, etc., according to methods known to those skilled in the art. In some embodiments, the starting powders of yttrium oxide, magnesium oxide, zirconium oxide and / or aluminum oxide may be optionally calcined according to methods known to those skilled in the art. Starting powders, powder mixtures and calcined powder mixtures having a high specific surface area (SSA), such as those exceeding 20 m 2 / g of those nanopowders cause processability problems when loading the powders in the tool set, achieving uniform particle dispersion and mixing during the powder combining / mixing step, and forming the first layer comprising the YAG phase during the in-situ reactive sintering method for forming YAG, as disclosed in International Application No. PCT / US20 / 60918, which is incorporated herein by reference. The starting powder according to the method as disclosed herein comprises yttrium oxide, magnesium oxide, zirconium oxide, and aluminum oxide, and preferably has an average particle size of 18 m / s. 2 / g and a smaller specific surface area. Therefore, it is preferred that the powder mixture as disclosed herein does not contain or substantially does not contain the nanopowder as disclosed herein and has a specific surface area of ​​about 18m 2 / g and smaller specific surface area (SSA).

[0342] The specific surface area is less than about 0.75m 2Starting powders, powder mixtures, and / or calcined powder mixtures with surface areas within this range may agglomerate, requiring higher mixing energies and extended mixing times to combine to form the powder mixtures disclosed herein. In addition, powders with surface areas within this range may reduce the driving force required for sintering to high densities as disclosed herein, thereby producing sintered ceramic bodies with lower density and higher porosity. Preferred for use in the disclosed methods are powders as disclosed herein having a surface area of ​​1 m³ / g as measured according to ASTM C1274. 2 / g to 18m 2 / g, preferably 2m 2 / g to 15m 2 / g and preferably 3m 2 / g to 12m 2 / g of SSA starting powder.

[0343] The d10 particle size of the yttrium oxide powder used as starting material according to embodiments as disclosed herein is preferably 1 μm to 6 μm, preferably 1 μm to 5 μm, preferably 1 μm to 4 μm, preferably 2 μm to 6 μm, preferably 3 μm to 6 μm, preferably 4 μm to 6 μm, preferably 2 μm to 4 μm.

[0344] The d50 particle size of the yttrium oxide powder used as a starting material according to the embodiments disclosed herein is preferably 3 μm to 9 μm, preferably 3 μm to 8.5 μm, preferably 3 μm to 8 μm, preferably 3 μm to 7 μm, preferably 4 μm to 9 μm, preferably 5 μm to 9 μm, preferably 6 μm to 9 μm, preferably 4 μm to 8 μm. The yttrium oxide powder as disclosed herein may have an average particle size of about 5 μm to 9 μm.

[0345] The d90 particle size of the yttrium oxide powder used as starting material according to embodiments as disclosed herein is preferably 6 μm to 16 μm, preferably 6 μm to 15 μm, preferably 6 μm to 14 μm, preferably 6.5 μm to 16 μm, preferably 7 μm to 16 μm, preferably 7.5 μm to 16 μm, preferably 7.5 μm to 14 μm.

[0346] Yttrium oxide powder usually has 2m 2 / g to 10m 2 / g, preferably 2m 2 / g to 8m 2 / g, preferably 2m 2 / g to 6m 2 / g, preferably 3m 2 / g to 10m 2 / g, preferably 4m 2 / g to 10m 2 / g, preferably 6m 2 / g to 10m 2 / g and preferably 2m2 / g to 4m 2 / g of specific surface area (SSA).

[0347] The purity of the yttrium oxide starting material is preferably greater than 99.99%, preferably greater than 99.995%, preferably greater than 99.999%, more preferably greater than 99.9995% and more preferably about 99.9999%. This corresponds to impurity levels of 100 ppm and less, preferably 50 ppm and less, preferably 25 ppm and less, preferably 10 ppm and less, more preferably about 1 ppm, preferably 1 ppm to 100 ppm, preferably 1 ppm to 50 ppm, preferably 1 ppm to 25 ppm, preferably 1 ppm to 10 ppm, preferably 1 ppm to 5 ppm.

[0348] The average particle size or d50 particle size of the magnesium oxide powder used as a starting material according to embodiments as disclosed herein is typically 1.5 to 5.5 μm, 2 to 5.5 μm, 2.5 to 5.5 μm, 3 to 5.5 μm, 1.5 to 5 μm, 1.5 to 4.5 μm, more preferably 2 to 4.5 μm.

[0349] The d90 particle size of the magnesium oxide powder used as starting material according to embodiments as disclosed herein is typically 4 to 9 μm, preferably 5 to 9 μm, preferably 6 to 9 μm, preferably 4 to 8 μm, preferably 4 to 7 μm and more preferably 5 to 7.5 μm.

[0350] Magnesium oxide powder usually has a 0.5m 2 / g to 10m 2 / g, preferably 0.5m 2 / g to 8m 2 / g, preferably 0.5m 2 / g to 6m 2 / g, preferably 1m 2 / g to 10m 2 / g, preferably 2m 2 / g to 10m 2 / g, preferably 3m 2 / g to 10m 2 / g and more preferably 2m 2 / g to 6m 2The magnesium oxide starting material preferably has a purity of greater than 99.99%, preferably greater than 99.995%, more preferably greater than 99.9975%, preferably greater than 99.999%, and preferably greater than 99.9992%, as measured using ICPMS methods known in the art. Accordingly, the magnesium oxide powder may have an impurity content of 100 ppm and less, preferably 50 ppm and less, preferably 25 ppm and less, and preferably about 10 ppm.

[0351] The zirconium oxide powder according to step a) can be selected from the group consisting of unstabilized, partially stabilized, and stabilized zirconium oxide. The reaction between the zirconium oxide and yttria powders to form at least one crystalline phase allows the use of any zirconium oxide powder without requiring the tetragonal / monoclinic phase transition that occurs with stable phase-pure zirconium oxide. Thus, the zirconium oxide powder forming the at least one first layer can comprise any one or a combination of unstabilized, partially stabilized, and stabilized zirconium oxide. Additional powder characteristics of the zirconium oxide and aluminum oxide (based on the second powder mixture) are disclosed in step b) of the method below.

[0352] Combining powders of at least two of aluminum oxide, magnesium oxide, and yttrium oxide and at least one of unstabilized zirconium oxide, partially stabilized zirconium oxide, and stabilized zirconium oxide to prepare at least a first powder mixture and at least a second powder mixture (according to either or both steps a) and b) can be performed using powder preparation techniques such as wet or dry ball milling (axial rotation), wet or dry tumbling (upside-down or vertical) mixing, jet milling, and combinations thereof. The use of these powder combining methods provides a high-energy process for breaking down fine particles and agglomerates.

[0353] Using dry conditions, the starting powder can be ball milled or upside-down / tumble mixed using high purity (>99.9%) alumina media to maintain the purity of the starting powder during mixing. In other embodiments, harder media such as zirconia media can be used to break up hard agglomerates. High purity alumina media was tested using the ICPMS method disclosed herein and found to be 99.9% to about 99.99% pure. The use of zirconia media can produce trace amounts (such as less than 100 ppm) of zirconia in the multilayer sintered ceramic body. The media used for dry ball milling can have a range of sizes, for example, 5 mm to 15 mm in diameter, with a loading added of about 50% to about 100% by weight of the powder. The media used for dry tumble mixing can include at least one large size (about 20 mm to 40 mm diameter) media element, without limitation. In some embodiments, the dry ball milling and / or dry type tumbling mixing can be carried out for 12 hours to 48 hours, preferably 16 hours to 48 hours, preferably 16 hours to 24 hours, preferably 18 hours to 22 hours duration.Dry ball milling or tumbling mixing process (axial rotation) can use the RPM of 50RPM to 250RPM, preferably 75RPM to 200RPM, preferably 75RPM to 150RPM, preferably 100RPM to 125RPM, each for the container with an approximately 200mm diameter.RPM can change according to the size of the container selected to use, and therefore, those diameters can have corresponding lower RPM greater than the container of for example 200mm, as known by persons skilled in the art.Dry method upside down / tumbling mixing can be carried out under the RPM of 10rpm to 30rpm, preferably about 20RPM. After dry ball milling and / or upside-down / tumbling ball milling / mixing, the powder mixture can optionally be sieved using a number of screens that can have openings of, for example, 45 μm to 400 μm, and blended, but there is no limitation as to the repetition or sequence known to those skilled in the art.

[0354] Wet ball milling or wet upside down / tumbling mixing can be carried out by suspending the starting powder in various solvents (such as ethanol, methanol and other alcohols) to form a slurry. The slurry in any process (ball milling or tumbling ball milling / mixing) can be formed to have a powder loading of 25% to 75% by weight of powder during grinding or mixing, preferably 40% to 75% by weight of powder, preferably 50% to 75% by weight of powder. Wet ball milling or wet upside down / tumbling mixing can improve the dispersion of powder by increasing fluidity, thereby producing a fine, uniform mixing before heat treatment or calcining. In an embodiment, many commercially available dispersants (such as polymethyl methacrylate (PMMA) and polyvinyl pyrrolidone (PVP)) and other dispersants known to those skilled in the art can be optionally used to add a dispersant to the slurry. A dispersant can optionally be added in an amount of 0.05% to 0.2% by weight of powder, preferably 0.05% to 0.1% by weight of powder. The medium load of wet ball milling or wet tumbling / upside-down mixing can be from 30% to 100% by powder weight, preferably 30% to 75% by powder weight, preferably 30% to 60% by powder weight.Wet ball milling or tumbling mixing can carry out the duration of 8 hours to 48 hours, preferably 12 hours to 48 hours, preferably 16 hours to 48 hours, preferably 8 hours to 36 hours, preferably 8 hours to 24 hours, preferably 16 hours to 24 hours, preferably 12 hours to 24 hours.Ball milling can use the RPM of 50RPM to 250RPM, preferably 75RPM to 200RPM, preferably 75RPM to 150RPM, preferably 100RPM to 125RPM, each for the container with about 200mm diameter.RPM can change according to the size of the container selected to use, and those diameters can have corresponding lower RPM greater than the container of for example 200mm, as known to those skilled in the art. Wet upside-down / tumbling mixing can be performed at an RPM of 10 to 30 rpm, preferably about 20 rpm. After wet ball milling and / or wet upside-down / tumbling mixing, the powder mixture can be optionally sieved using a plurality of sieves that can have openings of, for example, 45 μm to 400 μm, and blended, but there is no limitation on the repetition or sequence known to those skilled in the art.

[0355] The jet milling process known to those skilled in the art can also be used to thoroughly mix powders to form a powder, powder mixture, or calcined powder mixture with a narrow particle size distribution. Jet milling uses a high-speed jet of inert gas or air to collide particles of a starting powder and / or powder mixture and / or calcined powder mixture without using a grinding or mixing medium, thereby maintaining the initial purity of the powder to be milled. The chamber can be designed so that the size of larger particles can be preferentially reduced, which can provide a narrow particle size distribution in the final powder, powder mixture, or calcined powder mixture. The powder leaves the jet milling chamber when it reaches a predetermined particle size determined in the machine settings before processing, thereby ending the process. The starting powder, powder mixture, and / or calcined powder mixture as disclosed herein can be jet milled at a pressure of about 100 psi, either alone or in combination with any or all of the powder milling / mixing methods disclosed herein. After jet milling, the powder or powder mixture can optionally be sieved using a plurality of screens having openings of, for example, 45 μm to 400 μm, and blended, but there is no limitation on the repetition or sequence known to those skilled in the art.

[0356] Additional powder preparation procedures of milling, high shear mixing, planetary milling and other known procedures may also be applied.The foregoing powder preparation techniques may be used alone or in any combination thereof, or for more than one powder mixture that is then sintered to form a monolithic multilayer sintered ceramic body.

[0357] As known to those skilled in the art, when using a wet mixing or grinding process, the slurry can be dried by a rotary evaporation method, for example, at a temperature of about 40° C. to 90° C. for a duration of 1 to 4 hours, depending on the volume of the slurry to be dried. In other embodiments, the slurry can be dried using spray drying techniques known to those skilled in the art. After drying, the powder mixture can optionally be sieved using a sieve with an opening of, for example, 45 μm to 400 μm, and blended, but there is no limitation on repetition or sequence. The above-mentioned powder preparation techniques can be used alone or in any combination thereof.

[0358] After drying, the specific surface area of ​​the powder mixture of step a) may be 2 m 2 / g to 18m 2 / g, preferably 2m 2 / g to 17m 2 / g, preferably 2m 2 / g to 14m 2 / g, preferably 2m 2 / g to 12m 2 / g, preferably 2m 2 / g to 10m 2 / g, preferably 4m2 / g to 17m 2 / g, preferably 6m 2 / g to 17m 2 / g, preferably 8m 2 / g to 17m 2 / g, preferably 10m 2 / g to 17m 2 / g, preferably 4m 2 / g to 12m 2 / g, preferably 4m 2 / g to 10m 2 / g and preferably 5m 2 / g to 8m 2 / g.

[0359] By using high purity grinding media, such as alumina media having a purity of 99.99% and higher, the purity of the powder mixture can be maintained from the purity of the starting material after mixing / grinding. In some embodiments, it may be preferred to use zirconium oxide grinding media, and zirconium oxide may be introduced to the extent that an amount of 15 ppm to 100 ppm, 15 ppm to 75 ppm, preferably 15 ppm to 60 ppm, preferably 20 ppm to 30 ppm remains in at least one first layer and / or at least one second layer of the multi-layer sintered ceramic body.

[0360] Step b) of the method disclosed herein comprises combining alumina powder and zirconia powder to prepare a second powder mixture, wherein the zirconia powder comprises at least one of partially stabilized zirconia powder and stabilized zirconia powder; combining and mixing the starting powder materials comprising the second powder mixture in proportions such that the second powder mixture forms at least one second layer 102 upon sintering, wherein the at least one second layer 102 comprises at least one of partially stabilized zirconia and stabilized zirconia (and combinations thereof) in an amount of not less than 5% by volume ZrO2 and not more than 30% by volume ZrO2, and the balance comprises Al2O3. The starting powder material selected for forming the at least one second layer 102 is preferably a high-purity commercially available powder. However, other oxide powders, such as those produced by chemical synthesis processes and related methods, may be used as long as the high purity requirements are met. In some embodiments, depending on the desired CTE matching characteristics, toughness, and mechanical strength requirements of the plasma processing chamber component, the at least one second layer 102 may include at least one of partially stabilized zirconia and stabilized zirconia (and combinations thereof) in an amount of not less than 10 vol% ZrO2 and not more than 25 vol% ZrO2 relative to the volume of the at least one second layer 102 (with the balance comprising Al2O3).

[0361] The following characteristics of the zirconium oxide and aluminum oxide powders also apply to step a), except that the zirconium oxide of step a) may comprise any one or a combination of unstabilized zirconium oxide, partially stabilized zirconium oxide, and stabilized zirconium oxide. The zirconium oxide powder according to step b) is preferably stabilized, partially stabilized, or a combination thereof.

[0362] The zirconia powder may have a particle size distribution with d10 of 0.08 to 0.20 μm, d50 of 0.3 to 0.7 μm, and d90 of 0.9 to 5 μm. The zirconia powder used as a starting material for the mixture according to one embodiment of the present invention may have an average particle size of 0.3 to 1 μm.

[0363] Zirconia powders typically have a 1 m 2 / g to 16m 2 / g, preferably 2m 2 / g to 14m 2 / g, preferably 4m 2 / g to 12m 2 / g and more preferably 5m 2 / g to 9m 2 / g of specific surface area (SSA).

[0364] The purity of the zirconium oxide powder starting material is typically greater than 99.8%, preferably greater than 99.9%, preferably greater than 99.95%, preferably greater than 99.975%, preferably greater than 99.99%, and preferably greater than 99.995%. This corresponds to a total impurity content of 2000 ppm and less, preferably 1000 ppm and less, preferably 500 ppm and less, preferably 250 ppm and less, preferably 100 ppm and less, preferably 50 ppm and less, and preferably 25 ppm to 150 ppm, as measured using the ICPMS method disclosed herein. As is common in many commercially available zirconium oxide powders, the zirconium oxide used in the embodiments disclosed herein contains a low amount of Hf, approximately 2% to 5% by weight. These purities of the zirconium oxide exclude Hf and any stabilizing compounds as disclosed in Table 1.

[0365] In an embodiment, the zirconium oxide powder may include stabilizing compounds including at least one selected from the group consisting of yttrium oxide, lanthanum oxide (La2O3), cerium oxide (CeO2), magnesium oxide, samarium oxide (Sm2O3), and calcium oxide, and combinations thereof. To form partially stabilized zirconium oxide (PSZ), each of these stabilizing compounds may be present in an amount of 0.5 mol% to 50 mol%, preferably 0.5 mol% to 30 mol%, preferably 0.5 mol% to 15 mol%, preferably 0.5 mol% to 10 mol%, preferably 1 mol% to 50 mol%, preferably 1 mol% to 30 mol%, preferably 1 mol% to 10 mol%, preferably 1 mol% to 5 mol%, and preferably about 3 mol%. To form stabilized zirconia (SZ), these stabilizing compounds may each be present in an amount from greater than 6 mol% to about 45 mol%, preferably from greater than 10 mol% to about 45 mol%, preferably from greater than 25 mol% to about 45 mol%, preferably from greater than 6 mol% to 30 mol%, preferably from greater than 6 mol% to about 15 mol%, preferably from greater than 8 mol% to 15 mol%. Table 1 provides additional guidance for stabilized or partially stabilized zirconia.

[0366] In certain embodiments, at least one second layer 102 is yttria-stabilized and is formed from a powder mixture comprising alumina and zirconia, wherein the zirconia is selected from the group consisting of yttria-partially stabilized zirconia (PYSZ) or yttria-fully stabilized zirconia (YSZ). Yttria-partially stabilized zirconia (PYSZ) can be formed from a powder mixture comprising about 1 mol% to 10 mol% yttria, preferably 1 mol% to 8 mol% yttria, preferably 1 mol% to 5 mol% yttria, preferably 2 mol% to 4 mol% yttria, and preferably about 3 mol% yttria. Yttria-stabilized zirconia (YSZ) can be formed from a powder mixture comprising about 8 mol% to about 15 mol% yttria, preferably 10 mol% to 15 mol% yttria, and preferably 12 mol% to 15 mol% yttria.

[0367] The alumina powders constituting the first powder mixture and the second powder mixture have powder characteristics as disclosed below.

[0368] The d10 particle size of the aluminum oxide powder used as the starting material according to embodiments of the present disclosure is preferably 0.1 μm to 0.5 μm, preferably 0.1 μm to 0.4 μm, preferably 0.1 μm to 0.3 μm, preferably 0.2 μm to 0.5 μm, preferably 0.3 μm to 0.5 μm, preferably 0.4 μm to 0.5 μm, preferably 0.1 μm to 0.2 μm.

[0369] The d50 particle size of the aluminum oxide powder used as the starting material according to embodiments of the present disclosure is preferably 2 to 8 μm, preferably 2 to 7 μm, preferably 2 to 6 μm, preferably 3 to 8 μm, preferably 4 to 8 μm, preferably 5 to 8 μm and more preferably 2.5 to 5 μm.

[0370] The d90 particle size of the alumina powder used as a starting material according to embodiments of the present disclosure is preferably 15 to 40 μm, preferably 15 to 30 μm, preferably 15 to 25 μm, preferably 20 to 40 μm, preferably 30 to 40 μm and more preferably 20 to 30 μm.

[0371] The specific surface area of ​​alumina powder is usually 4m 2 / g to 18m 2 / g, preferably 4m 2 / g to 14m 2 / g, preferably 4m 2 / g to 10m 2 / g, preferably 4m 2 / g to 6m 2 / g, preferably 6m 2 / g to 18m 2 / g, preferably 6m 2 / g to 14m 2 / g, preferably 8m 2 / g to 18m 2 / g, preferably 10m 2 / g to 18m 2 / g, preferably 8m 2 / g to 10m 2 / g, and preferably 6m 2 / g to 10m 2 / g.

[0372] The purity of the aluminum oxide starting material is typically greater than 99.99%, preferably greater than 99.995%, preferably greater than 99.999%, and preferably greater than 99.9995%, as measured using ICPMS. Accordingly, the impurity content of the aluminum oxide powder may be 100 ppm and less, preferably 50 ppm and less, preferably 25 ppm and less, preferably 10 ppm and less, and more preferably 5 ppm and less.

[0373] The alumina and zirconia powders are mixed in proportions such that the zirconia is each present in an amount of 10% to 30%, preferably 10% to 25%, preferably 10% to 20%, preferably 15% to 25%, preferably 20% to 25% and preferably 15% to 20% by volume of the at least one second layer 102 of the multi-layer sintered ceramic body (when sintered).

[0374] Combining powders of alumina and at least one of partially stabilized zirconia and stabilized zirconia to prepare a second powder mixture can be performed according to the materials and methods disclosed in step a) of the method.

[0375] Step c) of the method disclosed herein comprises combining alumina, yttrium oxide, and at least one of unstabilized zirconia, partially stabilized zirconia, and stabilized zirconia to prepare at least one third powder mixture. The at least one third powder mixture may comprise alumina in an amount ranging from greater than 43% to 92.5% and less, yttrium oxide in an amount ranging from 1% to 56% and less, and at least one of unstabilized zirconia, partially stabilized zirconia, and stabilized zirconia in an amount ranging from 0.4% and greater to 40%, each by weight of the at least one third powder mixture. Preferably, the at least one third powder mixture has a particle size of about 1 m 2 / g to 18m 2 / g, preferably about 1m 2 / g to about 14m 2 / g, preferably about 1m 2 / g to about 10m 2 / g, preferably about 1m 2 / g to about 8m 2 / g, preferably about 2m 2 / g to about 18m 2 / g, preferably about 2m 2 / g to about 14m 2 / g, preferably about 2m 2 / g to about 10m 2 / g, preferably about 3m 2 / g to about 9m 2 / g, preferably about 3m 2 / g to about 6m 2 / g SSA. In a preferred embodiment, the at least one third powder mixture may comprise approximately 73% alumina, approximately 6% yttrium oxide, and approximately 21% of at least one of unstabilized zirconia, partially stabilized zirconia, and stabilized zirconia, each by weight of the at least one third powder mixture. In a further preferred embodiment, the at least one third powder mixture comprises approximately 73% alumina, approximately 6% yttrium oxide, and approximately 21% of 3 mol% yttrium oxide partially stabilized zirconia, each by weight of the at least one third powder mixture. Upon sintering, the at least one third powder mixture forms at least one third layer 103 having a plurality of phases comprising YAG, alumina, and at least one of unstabilized zirconia, partially stabilized zirconia, and stabilized zirconia. In other embodiments, upon sintering, the at least one third powder mixture may form a YAG phase in batches and thus comprise approximately 43 wt% alumina and 57 wt% yttrium oxide. The at least one third layer comprising YAG will have a CTE matched to the at least one first layer comprising YAG within the disclosed ranges.

[0376] Combining the yttrium oxide, aluminum oxide, and zirconium oxide powders to prepare a third powder mixture can be performed according to the powder materials and methods disclosed in steps a) and b) of the method. The third powder mixture can be subjected to dry ball milling, roller blending, wet grinding, wet tumbling mixing, and other similar mixing methods known to those skilled in the art.

[0377] As previously disclosed, powders of at least two of aluminum oxide, yttrium oxide, and magnesium oxide and at least one of unstabilized zirconium oxide, partially stabilized zirconium oxide, and stabilized zirconium oxide are combined to prepare at least a first powder mixture, a second powder mixture, and a third powder mixture (according to any one or both of steps a), b), and c). This can be performed using powder preparation techniques such as wet or dry ball milling (axial rotation), wet or dry tumbling (upside-down or vertical) mixing, jet milling, and combinations thereof. The use of these powder combining methods provides a high-energy process for breaking down fine particles and agglomerates.

[0378] Step d) of the method disclosed herein includes calcining at least one of the first, second, and third powder mixtures by applying heat to raise the temperature of at least one of the first, second, and third powder mixtures to a calcination temperature and maintaining the calcination temperature for calcination, thereby forming at least one of the first, second, and third calcined powder mixtures. This step can be performed so that moisture can be removed and the surface condition of the powder mixture is uniform before sintering. Calcination can be performed at a temperature of 600°C to 1200°C, preferably 600°C to 1100°C, preferably 600°C to 1000°C, preferably 600°C to 900°C, preferably 700°C to 1100°C, preferably 800°C to 1100°C, preferably 800°C to 1000°C, and preferably 850°C to 950°C. Calcination can be performed in an oxygen-containing environment for a duration of 4 to 12 hours, preferably 4 to 10 hours, preferably 4 to 8 hours, preferably 6 to 12 hours, and preferably 4 to 6 hours. After calcination, at least one of the first, second, and third powder mixtures can be sieved and / or tumbled and / or blended according to known methods to form at least one first, second, and third calcined powder mixtures. Preferably, the at least one first powder mixture is calcined. Calcination may or may not result in a reduction in specific surface area.

[0379] The first powder mixture may have a d10 particle size of 0.06 μm to 4 μm, preferably 0.08 μm to 4 μm, preferably 0.1 μm to 4 μm, preferably 0.2 μm to 4 μm, preferably 0.3 μm to 4 μm, preferably 0.4 μm to 4 μm, preferably 0.08 μm to 3 μm, preferably 0.08 μm to 2 μm, preferably 0.08 μm to 1 μm, preferably 0.5 μm to 3 μm, preferably 1 μm to 2 μm, preferably 1 μm to 3 μm.

[0380] The second powder mixture may have a d10 particle size of 0.075 μm to 0.4 μm, preferably 0.075 μm to 0.3 μm, preferably 0.075 μm to 0.2 μm, preferably 0.1 μm to 0.4 μm, preferably 0.1 μm to 0.3 μm, preferably 0.1 μm to 0.2 μm, and preferably about 0.2 μm.

[0381] The first powder mixture may have a d50 particle size of 0.7 μm to 50 μm, preferably 1 μm to 40 μm, preferably 1 μm to 30 μm, preferably 1 μm to 20 μm, preferably 1 μm to 10 μm, preferably 1 μm to 5 μm, preferably 5 μm to 50 μm, preferably 10 μm to 50 μm, preferably 20 μm to 50 μm, preferably 30 μm to 50 μm, preferably 3 μm to 8 μm, preferably 5 μm to 10 μm, and preferably 6 μm to 15 μm.

[0382] The second calcined powder mixture may have a d50 particle size of 1 μm to 100 μm, preferably 1 μm to 80 μm, preferably 1 μm to 60 μm, preferably 1 μm to 40 μm, preferably 10 μm to 100 μm, preferably 20 μm to 100 μm, preferably 30 μm to 100 μm, preferably 20 μm to 80 μm, preferably 20 μm to 60 μm, and preferably 20 μm to 40 μm.

[0383] The first calcined powder mixture may have a particle size of 10 μm to 350 μm, preferably 10 μm to 300 μm, preferably 10 μm to 250 μm, preferably 10 μm to 200 μm, preferably 10 μm to 175 μm, preferably 10 μm to 150 μm, preferably 10 μm to 100 μm, preferably 10 μm to 75 μm, preferably 10 μm to 50 μm, preferably 10 μm to 40 μm, Preference is given to a particle size d90 of 10 to 25 μm, preferably 20 to 350 μm, preferably 40 to 350 μm, preferably 60 to 350 μm, preferably 100 to 350 μm, preferably 150 to 350 μm, preferably 200 to 350 μm, preferably 12 to 330 μm, preferably 100 to 330 μm, preferably 100 to 250 μm.

[0384] The second calcined powder mixture may have a d90 particle size of 20 to 250 μm, preferably 20 to 220 μm, preferably 20 to 150 μm, preferably 20 to 100 μm, preferably 50 to 220 μm, preferably 70 to 220 μm, preferably 100 to 220 μm.

[0385] In certain embodiments, the higher temperature calcination conditions as disclosed herein may result in the formation of crystalline phases and agglomeration of the calcined powder mixture, thereby resulting in greater variability in the overall particle size distribution, and in particular, in a greater variety of overall d50 and d90 particle sizes. In other embodiments, the lower temperature calcination conditions as disclosed herein may not affect the particle size distribution of the calcined powder mixture relative to the starting material, and thus the particle size distribution is within the same or similar range as the starting powder material. Batch-to-batch variation and heat transfer management during calcination may also contribute to variations in particle size distribution. Thus, a wide range of particle size distributions, and in particular d50 and d90 particle sizes of the powder mixture, may be produced by the calcination conditions disclosed herein.

[0386] At least one of the first calcined powder mixture, the second calcined powder mixture, and the third calcined powder mixture may each have a particle size of about 1 m 2 / g to about 18m 2 / g, preferably about 1m 2 / g to about 14m 2 / g, preferably about 1m 2 / g to about 10m 2 / g, preferably about 1m 2 / g to about 8m 2 / g, preferably about 2m 2 / g to about 18m 2 / g, preferably about 2m 2 / g to about 14m 2 / g, preferably about 2m 2 / g to about 12m 2 / g, preferably about 2m 2 / g to about 10m 2 / g, preferably about 3m 2 / g to about 9m 2 / g, and preferably about 3m 2 / g to about 6m 2 / g of specific surface area (SSA).

[0387] The first calcined powder mixture may have a total impurity content of 5 ppm to 200 ppm, preferably 5 ppm to 150 ppm, preferably less than 100 ppm, preferably less than 75 ppm, preferably less than 50 ppm, preferably less than 25 ppm, preferably less than 15 ppm, preferably less than 10 ppm, preferably less than 8 ppm, preferably less than 5 ppm, preferably 5 ppm to 50 ppm, preferably 5 ppm to 30 ppm, preferably 3 ppm to 20 ppm, relative to the mass of the first calcined powder mixture.

[0388] Table 11 shows the ICPMS purity results for the exemplary first powder mixture prior to forming the polycrystalline YAG layer.

[0389] Table 11

[0390]

[0391] *N / A indicates the elements present in the starting powders forming the powder mixture.

[0392] Table 12 shows the ICPMS purity results for the exemplary first powder mixture before forming the spinel layer.

[0393] Table 12

[0394]

[0395] *N / A indicates the elements present in the starting powders forming the powder mixture.

[0396] Table 13 shows the ICPMS purity results for the exemplary first powder mixture prior to forming the yttria-zirconia layer.

[0397] Table 13

[0398]

[0399]

[0400] *N / A indicates the elements present in the starting powders forming the powder mixture;

[0401] For each of Tables 10-14, N / D indicates that the element was detected below the reporting limit of ICPMS. The reported purity is the average of 5 batches of powder mixture.

[0402] The second powder mixture may have a total impurity content of 5 ppm to 200 ppm, preferably 5 ppm to 150 ppm, preferably less than 100 ppm, preferably less than 50 ppm, preferably less than 25 ppm, preferably less than 15 ppm, preferably 10 ppm to 100 ppm, preferably 10 ppm to 80 ppm, preferably 10 ppm to 60 ppm, preferably 10 ppm to 40 ppm, preferably 20 ppm to 80 ppm, preferably 30 ppm to 60 ppm, relative to the mass of the second powder mixture.

[0403] Table 14 shows the ICPMS purity results for the exemplary second powder mixture prior to forming the at least one second layer 102 .

[0404] Table 14

[0405]

[0406]

[0407] The results in Table 14 are averages of five powder batches. As depicted in Table 14, the second powder mixture can include magnesium oxide in an amount of about 5 ppm and less, preferably 3 ppm and less, as measured relative to the mass of the at least one second powder mixture. The powder mixture comprising aluminum oxide and at least one of stabilized zirconium oxide and partially stabilized zirconium oxide as disclosed herein is free or substantially free of dopants and / or sintering aids as disclosed herein. Hf, Y, and Zr are not considered impurities, dopants, or sintering aids and are not listed in Table 14.

[0408] The starting...

Claims

1. A method for preparing a multilayer sintered ceramic body, the method comprising the following steps: a. combining powders comprising yttrium oxide and aluminum oxide to prepare a first powder mixture, wherein the powders in the first powder mixture are mixed in proportion to form YAG; b. combining alumina powder with at least one of an unstable zirconia powder, a partially stabilized zirconia powder, and a stabilized zirconia powder to prepare a second powder mixture, wherein the powders in the second powder mixture are mixed in proportions such that the powders comprise 10% to 30% zirconia by volume during sintering; c. combining aluminum oxide powder, yttrium oxide powder, and at least one of unstabilized zirconium oxide powder, partially stabilized zirconium oxide powder, and stabilized zirconium oxide powder to produce at least one third powder mixture, wherein the third powder mixture is a combination of the first powder mixture and the second powder mixture; d. calcining at least one of the first powder mixture, the second powder mixture, and the third powder mixture by applying heat to raise the temperature of at least one of the first powder mixture, the second powder mixture, and the third powder mixture to a calcination temperature and maintaining the calcination temperature for calcination, thereby forming at least one of a first calcined powder mixture, a second calcined powder mixture, and a third calcined powder mixture; e. separately disposing the first powder mixture, the second powder mixture, and the third powder mixture in an interior volume defined by a tool set of a sintering apparatus to form at least one layer of the first powder mixture, at least one layer of the second powder mixture, and at least one layer of the third powder mixture, and generating a vacuum condition within the volume, wherein the tool set comprises a die, the die comprising a sidewall, the sidewall comprising an inner wall and an outer wall, wherein the inner wall has a diameter defining the interior volume capable of receiving the powder; and an upper punch and a lower punch operably coupled to the die, wherein each of the upper punch and the lower punch has an outer wall defining a diameter that is smaller than the diameter of the inner wall of the die, thereby defining a gap between each of the upper punch and the lower punch and the inner wall of the die when at least one of the upper punch and the lower punch moves within the interior volume of the die, wherein the gap is 10 μm to 100 μm wide; f. applying pressure to the layers of the first powder mixture, the second powder mixture, and the third powder mixture while heating to a sintering temperature and sintering to form the multilayer sintered ceramic body, wherein the at least one layer of the first powder mixture forms at least one first layer, the at least one layer of the second powder mixture forms at least one second layer, and the at least one layer of the third powder mixture forms at least one third layer; and g. lowering the temperature of the multilayer sintered ceramic body, wherein the at least one first layer comprises polycrystalline YAG and the at least one second layer comprises aluminum oxide, wherein the aluminum oxide comprises at least one of unstable zirconium oxide, stable zirconium oxide, and partially stabilized zirconium oxide, and the at least one third layer comprises yttrium oxide, aluminum oxide, and at least one of unstabilized zirconium oxide, stable zirconium oxide, and partially stabilized zirconium oxide, wherein the at least one second layer is disposed between the at least one first layer and the at least one third layer.

2. The method of claim 1, wherein the first powder mixture, the second powder mixture, and the third powder mixture have a combined total impurity content of 200 ppm and less as measured using ICPMS.

3. The method according to claim 1 or 2, wherein the second powder mixture comprises partially stabilized zirconium oxide or stabilized zirconium oxide in an amount of not less than 15% and not more than 34% by weight relative to the weight of the second powder mixture.

4. The method of claim 1 or 2, wherein the first powder mixture, the second powder mixture and the third powder mixture are crystalline as determined by x-ray diffraction.

5. The method of claim 1 or 2, wherein the second powder mixture comprises partially stabilized zirconium oxide.

6. The method of claim 1 or 2, wherein the second powder mixture comprises yttria partially stabilized zirconia.

7. The method of claim 1 or 2, wherein the second powder mixture comprises 3 mol% yttria partially stabilized zirconia.

8. The method according to claim 1 or 2, wherein the pressure applied to the at least one first layer, the at least one second layer and the at least one third layer of the first powder mixture, the second powder mixture and the third powder mixture is 5 MPa to 100 MPa.

9. The method according to claim 1 or 2, wherein the temperature of the calcining step is 600°C to 1200°C.

10. The method according to claim 1 or 2, wherein the sintering temperature is 1000°C to 1700°C.

11. The method according to claim 1 or 2, further comprising the steps of: h. optionally annealing the multilayer sintered ceramic body by applying heat to raise the temperature of the multilayer sintered ceramic body to an annealing temperature for annealing; and i. Lowering the temperature of the annealed multi-layer sintered ceramic body.

12. The method according to claim 1 or 2, further comprising the steps of: j. machining the multilayer sintered ceramic body to form multilayer sintered ceramic parts in the shape of windows, covers, dielectric windows, RF windows, rings, focus rings, process rings, deposition rings, nozzles, injectors, gas injectors, showerheads, gas distribution plates, diffusers, ion suppressor elements, chucks, electrostatic wafer chucks (ESCs), and positioning plates.

13. A multi-layer sintered ceramic body produced by the method according to any one of claims 11 to 12.

14. The multi-layer sintered ceramic body of claim 13, having a maximum dimension of 100 mm to about 625 mm.

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