UV-activated red ceramic bodies containing YAG for use in semiconductor processing chambers.

Abstract

Disclosed herein is a sintered ceramic body comprising at least one layer comprising 90-99.8 volume percent polycrystalline yttrium aluminum garnet (YAG) and 15 ppm-500 ppm zirconium, the at least one layer comprising at least one surface, the at least one surface comprising pores having a pore size not exceeding 5 pm and having a maximum pore size of 1.5 pm for at least 95% of the pores, the at least one surface exhibiting an L* value of 50-77 and an "a" value of 6-12, the at least one layer having a thickness of 500 pm-2 cm, and the values ​​of L* and "a" varying by 10% or less across the at least one surface. Also disclosed is a method of making the same.

Description

[Technical Field]

[0001] The present disclosure relates to corrosion-resistant sintered ceramic bodies and components formed therefrom, methods for making the same, and their use in semiconductor plasma processing chambers. The sintered ceramic bodies exhibit a color defined in part by an L* value of 50 to 77. [Background technology]

[0002] Semiconductor processing requires the use of halogen-based gases, oxygen, and other gases in combination with high electric and magnetic fields to create a plasma etching environment. This plasma etching environment is created in a vacuum chamber for etching materials on semiconductor substrates. The harsh plasma etching environment requires the use of highly corrosion-resistant materials for the chamber components. These chambers include components such as disks or windows, liners, gas injectors, rings, and cylinders that confine the plasma over the wafer being processed. These components are formed from materials that provide resistance to corrosion and erosion in the plasma environment, as described, for example, in U.S. Patent Nos. 5,798,016, 5,911,852, 6,123,791, and 6,352,611. However, these components used in plasma processing chambers are continuously attacked by the plasma, resulting in corrosion, erosion, and roughening on the surfaces of chamber parts exposed to the plasma. This corrosion and erosion contribute to wafer-level contamination through the release of particles from the component surfaces into the chamber, resulting in yield loss for semiconductor devices.

[0003] Rare earth oxides, especially yttria alumina garnet (YAG) (Y3Al5O 12The family of related yttrium aluminum oxides, such as YAP (AlYO3) and YAM (Y4Al2O9), are known to have a wide range of technological and industrial applications. YAG, with its cubic crystallographic phase, has attracted much attention for applications such as host materials for solid-state lasers, transparent cladding, ballistic infrared window materials, and its combination of mechanical, thermal, and optical properties. Particularly for laser applications, single-crystal YAG is an ideal substrate due to its ability to host rare-earth dopants, and therefore, much effort has been expended to fabricate single-crystal YAG. In addition to optical applications, YAG is also known to be highly chemically inert and exhibit high halogen-based plasma corrosion and erosion resistance.

[0004] YAG-based ceramics are difficult to sinter to the high densities required for advanced applications that require minimal residual porosity in the final part. In semiconductor applications involving plasma corrosion, porosity can accelerate chemical attack on the surfaces of chamber components and generate particles as the surfaces deteriorate with extended use. In addition to reducing chemical resistance, excessive porosity can be detrimental to the mechanical and thermal properties of the ceramic, as known to those skilled in the art. Densification of YAG ceramics typically requires high temperatures, above approximately 1600°C, and long vacuum sintering times, such as 8 hours or more, to achieve theoretical densities >98%. To achieve higher densities closer to theoretical values, pressure-assisted densification techniques, such as hot isostatic pressing (HIP), are used after initial vacuum sintering to approximately 98% density or after direct uniaxial hot pressing (HP) from powder. High temperatures and long sintering times often result in excessive grain growth, adversely affecting the mechanical strength of the solid yttrium aluminum oxide body. Sintering aids such as silica (SiO2) are often used to promote densification of YAG ceramics. However, the addition of sintering aids effectively degrades the corrosion and erosion resistance of the yttrium aluminum oxide material and increases the likelihood of impurity contamination at the semiconductor device level during use in the chamber. Therefore, high purity and high density bodies of yttrium aluminum oxide, especially those with the cubic crystalline phase (YAG, Y3Al5O4), are required. 12 ) is desirable.

[0005] Yttrium aluminum oxide films or coatings are known to be deposited on bases or substrates made of different materials that are more readily available and have better mechanical and thermal properties. Such yttrium aluminum oxide films have been produced by several methods. However, these methods are limited in the film thickness that can be produced, exhibit poor adhesion between the film and the substrate, and high levels of volume porosity, resulting in particle shedding into the process chamber.

[0006] For high-density components fabricated from the YAG phase of yttrium aluminum oxide, a uniform microstructure is preferred to achieve uniform corrosion properties over large areas. Therefore, it is desirable to achieve high phase purity, with the majority (>90% by volume) of the body consisting of YAG, with minimal amounts of residual alumina, yttria, YAP, or YAM phases. However, fabricating 100% polycrystalline YAG yttrium aluminum oxide ceramic bodies is very difficult, and therefore, trace amounts (<1% by volume) of secondary oxide phases may be present. YAG, which follows the established yttria / alumina phase diagram, exists only as a linear compound following a stoichiometric composition; therefore, YAG forms phase-pure sintered bodies only over a very narrow compositional range. Any deviation from the nominal phase composition or incomplete reaction between the starting phases of the material can result in undesirable secondary phases in the final product.

[0007] Attempts to fabricate ceramic bodies for large-sized corrosion-resistant components made from YAG have so far failed. Solid, phase-pure, and high-chemical purity components with diameters on the order of 100 mm or greater that can be handled and used as part of a chamber without breakage or cracking are difficult to produce beyond the laboratory scale. Primarily, the aforementioned challenges can be attributed to the difficulty of sintering and the physical properties of YAG, including high thermal expansion and low thermal conductivity. Currently, there is no economically feasible method for producing high-purity, crystal-phase-pure YAG sintered bodies or components with diameters on the order of 100 mm to about 625 mm or greater for use in semiconductor etching and deposition applications.

[0008] Furthermore, plasma chamber components containing layers of YAG are known to change color over time with UV exposure. The color change is typically non-uniform and can lead to rejection by end users. A possible cause of coloration is migration of metals or metal-containing compounds from the substrate layer into the YAG layer during processing. Summary of the Invention [Problem to be solved by the invention]

[0009] As a result, there is a need for sintered ceramic bodies that have uniform and high density, low porosity, and high purity, that include YAG, and that provide improved plasma resistance to corrosion and erosion under plasma etching and deposition conditions, color uniformity that does not change with UV exposure, and a commercially viable manufacturing method that is particularly suited to the fabrication of large sized components.

[0010] To meet these and other needs, and with that objective in mind, the present disclosure provides embodiments of multilayer sintered ceramic bodies and methods for preparing large multilayer sintered ceramic bodies with improved mechanical, electrical, and thermal properties and handling capabilities.

[0011] Embodiment 1. A sintered ceramic body comprising at least one layer comprising 90% to 99.8% by volume polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconium, wherein the at least one layer comprises at least one surface, and the at least one surface is The pores include Pore ​​diameter not exceeding 5 μm death At least one surface exhibits an L* value of 50 to 77 and an a* value of 6 to 12, and at least one layer has a thickness of 500 μm to 2 cm, and the values ​​of L* and a* are Coefficient of variation is less than 10% over at least one surface be , sintered ceramic body.

[0012] Embodiment 2. The sintered ceramic body of embodiment 1, wherein at least one layer has a b* value of 3-6.

[0013] Embodiment 3. b* value Coefficient of variation is less than 15% across at least one surface be 3. The sintered ceramic body of embodiment 2.

[0014] Embodiment 4. The sintered ceramic body of any one of embodiments 1-3, wherein at least one layer comprises 15-100 ppm zirconium.

[0015] Embodiment 5. The sintered ceramic body of any one of embodiments 1 to 4, wherein at least one layer has a thickness of 500 μm to 1 cm.

[0016] Embodiment 6. The sintered ceramic body of embodiment 4, wherein at least one layer has a thickness of 500 μm to 5 mm.

[0017] Embodiment 7. Over at least one surface, L* Coefficient of variation is less than 3% can be , a* Coefficient of variation is less than 9% be 7. The sintered ceramic body according to any one of embodiments 1 to 6.

[0018] Embodiment 8. The sintered ceramic body of any one of embodiments 1-7, wherein the polycrystalline yttrium aluminum garnet comprises pores having a pore diameter not exceeding 1.75 μm for at least 97% or more of all pores.

[0019] Embodiment 9. The sintered ceramic body of any one of embodiments 1-8, wherein the at least one polycrystalline yttrium aluminum garnet has a maximum pore size not exceeding 2 μm for at least 99% or more of all pores.

[0020] Embodiment 10. The sintered ceramic body of any one of embodiments 1 to 9, wherein the polycrystalline yttrium aluminum garnet has a volume porosity of 0.1 to 3%.

[0021] Embodiment 11. The sintered ceramic body of embodiment 11, having a volume porosity of 0.1 to 2%.

[0022] Embodiment 12. The sintered ceramic body of embodiment 11, having a volume porosity of 0.1 to 0.5%.

[0023] Embodiment 13. The sintered ceramic body of any one of embodiments 1-12, wherein the polycrystalline yttrium aluminum garnet is present in an amount of 93-99.8 volume %, excluding any Al2O3 or zirconium present.

[0024] Embodiment 14. The sintered ceramic body of any one of embodiments 1-13, wherein the polycrystalline ceramic body has 50 ppm or less trace metal Na, Fe, and Mg impurities as determined by ICPMS.

[0025] Embodiment 15. The sintered ceramic body of any one of embodiments 1-14, wherein the pores occupy less than 0.2% of the surface area.

[0026] Embodiment 16. The sintered ceramic body of any one of embodiments 1-15, wherein the pores occupy less than 0.10% of the surface area.

[0027] Embodiment 17. The sintered ceramic body of any one of embodiments 1 to 16, having a maximum dimension of 100 mm to 625 mm.

[0028] Embodiment 18. The sintered ceramic body of embodiment 17, having a maximum dimension of 200 mm to 625 mm.

[0029] Embodiment 19. The sintered ceramic body of embodiment 17 or 18, having a density variance measured across its largest dimension of 0.2 to less than 5%.

[0030] Embodiment 20. The sintered ceramic body of embodiment 19, having a density variance measured across its largest dimension of 0.2 to 3%.

[0031] Embodiment 21. The sintered ceramic body of any one of embodiments 1 to 20, wherein at least one layer comprises up to 0.5% Al2O3.

[0032] Embodiment 22. A method for preparing a sintered ceramic body, comprising: a) combining an yttria powder, an alumina powder, and a zirconium-containing powder providing 15-500 ppm zirconium to form a first powder mixture; b) firing the first powder mixture by applying heat to raise the temperature of the first powder mixture to a firing temperature and maintaining the firing temperature to form a first fired powder mixture; c) disposing the first fired powder mixture within a volume defined by a toolset of a sintering apparatus to form at least one layer of the first fired powder mixture and creating a vacuum condition within the volume; and d) forming a first fired powder mixture by applying heat to the first powder mixture to raise the temperature of the first powder mixture to a firing temperature and maintaining the firing temperature to form a first fired powder mixture. a) applying pressure to at least one layer of a first fired powder mixture while heating to a sintering temperature to form a sintered ceramic body comprising at least one layer comprising 90 volume % to 99.8 volume % polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconium; b) reducing the temperature of the sintered ceramic body; and c) exposing the sintered ceramic body to UV radiation for a time period of 1 to 400 minutes, wherein the first fired powder mixture has a total impurity content of 150 ppm or less, and the yttria powder and alumina powder of step a) each have a total impurity content of about 18 ppm as measured in accordance with ASTM C1274. 2 / g or less, the sintered ceramic layer comprises at least one layer comprising 90 volume % to 99.8 volume % polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconium, the at least one layer comprising at least one surface, and the at least one surface The pores include Pore ​​diameter not exceeding 5 μm death , having a maximum pore diameter of 1.5 μm for at least 95% of the pores death At least one surface exhibits an L* value of 50 to 77 and an a* value of 6 to 12, and at least one layer has a thickness of 500 μm to 2 cm, and the values ​​of L* and a* are Coefficient of variation is less than 10% over at least one surface be , a method for preparing a sintered ceramic body.

[0033] Embodiment 23. The method of embodiment 22, further comprising the steps of: g) annealing the sintered ceramic body by applying heat to raise the temperature of the sintered ceramic body to an annealing temperature and performing the annealing; and h) lowering the temperature of the annealed multilayer sintered ceramic body; and i) optionally, machining the sintered ceramic body or the annealed sintered ceramic body to produce a sintered ceramic component in the shape of a dielectric window, an RF window, a focus ring, a process ring, a deposition ring, a nozzle or gas injector, a showerhead, a gas distribution plate, an etch chamber liner, a plasma source adapter, a gas inlet adapter, a diffuser, an electrostatic wafer chuck (ESC), a chuck, a puck, an ion suppressor element, a faceplate, an isolator, a spacer, and / or a guard ring in a plasma processing chamber.

[0034] Embodiment 24. The method of embodiment 22 or 23, wherein the toolset comprises a graphite die having a volume, an inner wall, and first and second openings, and first and second punches operatively coupled to the die, each of the first and second punches having an outer wall defining a diameter smaller than a diameter of the inner wall of the die, thereby forming a gap between each of the first and second punches and the inner wall of the die when at least one of the first and second punches moves within the volume of the die.

[0035] Embodiment 25. The method of embodiment 24, wherein the gap is a distance of 10 to 100 μm between the inner wall of the die and the outer wall of each of the first and second punches.

[0036] Embodiment 26. The method of any one of embodiments 22-25, wherein the sintering temperature is 1000-1500°C.

[0037] Embodiment 27. The method of any one of embodiments 22-26, wherein the sintering temperature is 1000-1300°C.

[0038] Embodiment 28. The method of any one of embodiments 22 to 27, wherein a pressure of 5 to 59 MPa is applied to the calcined powder mixture while heating to the sintering temperature.

[0039] Embodiment 29. The method of embodiment 28, wherein the pressure is 5 to 40 MPa.

[0040] Embodiment 30. The method of embodiment 29, wherein the pressure is 5 to 20 MPa.

[0041] Embodiment 31. The method of any one of embodiments 22-30, wherein a pressure of less than 50 MPa is applied to the calcined powder mixture while heating to the sintering temperature.

[0042] Embodiment 32. The method of any one of embodiments 22-31, wherein the sintered ceramic body has a maximum dimension of 100 mm to 625 mm.

[0043] Embodiment 33. The method of embodiment 32, wherein the sintered ceramic body has a maximum dimension of 200 mm to 625 mm.

[0044] Embodiment 34. The method of any one of embodiments 22-33, wherein the sintered ceramic body has a density variance measured across its largest dimension of 0.2 to less than 5%.

[0045] Embodiment 35. The method of embodiment 34, wherein the sintered ceramic body has a density variance, measured across its largest dimension, of 0.2 to 3%.

[0046] Embodiment 36. The method of any one of embodiments 22 to 35, wherein at least one surface exhibits a b* value of 3 to 6.

[0047] Embodiment 37. b* value Coefficient of variation of is less than 15% across at least one surface be 37. The method of embodiment 36.

[0048] Embodiment 38. The sintered ceramic body of embodiment 14, wherein the polycrystalline ceramic body has less than or equal to 5 ppm trace metal impurities of Na, Fe, and Mg as determined by ICPMS.

[0049] The embodiments of the present invention may be used alone or in combination with each other. [Brief explanation of the drawings]

[0050] [Figure 1] FIG. 1 shows a binary yttrium oxide / aluminum oxide phase diagram showing the yttrium aluminum oxide phases YAG (Y3Al5O12), YAP (YAlO3), and YAM (Y4Al2O9), as well as the molar ratios and temperatures required to form them. [Figure 2A] FIG. 2A is an SEM photomicrograph at 10,000x magnification of the polished surface of a sintered ceramic body made according to Example 2. [Figure 2B] FIG. 2B is a 10,000x SEM photomicrograph of the polished surface of a sintered ceramic body made according to Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0051] Reference will now be made in detail to certain embodiments. While the present disclosure will be described in conjunction with these specific implementations, it will be understood that the present disclosure is not limited to such specific embodiments. On the contrary, the present disclosure is intended to cover alternatives, modifications, and equivalents that may be included within the spirit and scope of the present invention as defined by the appended claims. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. The present disclosure may be practiced without some or all of these specific details.

[0052] Semiconductor etch and deposition reactors require reactor components with surfaces that are highly resistant to corrosion and erosion by the halogen-containing plasmas required for processing. The surfaces preferably minimize particle shedding from the component surface into the chamber. Additionally, chamber components must have sufficient mechanical strength for handleability and use, especially at large component sizes (greater than 100 mm in diameter, e.g., 100-625 mm). Sintered ceramic bodies may be machined into sintered components and therefore must be capable of being handled and machined at large sizes while providing corrosion resistance, low particle generation, and high mechanical strength. The sintered ceramic bodies disclosed herein comprise at least one layer comprising 90% to 99.8% by volume polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconium, the at least one layer comprising at least one surface, the at least one surface comprising at least one layer. contains pores, and the pores Pore ​​diameter not exceeding 5 μm death , having a maximum pore diameter of 1.5 μm for at least 95% of the pores death At least one surface exhibits an L* value of 50 to 77 and an a* value of 6 to 12, and at least one layer has a thickness of 500 μm to 2 cm, and the L* and a* values Coefficient of variation is less than 10% over at least one surface be These materials have excellent corrosion and erosion resistance. The use of these materials results in semiconductor plasma processing chamber components having surfaces that offer improved plasma resistance over other materials when subjected to halogen-based plasma etching and deposition conditions.

[0053] definition

[0054] As used herein, the term "yttrium aluminum oxide" means YAlO 12"YAG" is understood to mean at least one of the crystalline phase forms of yttrium aluminum oxide, including (YAG; yttrium aluminum garnet / cubic phase), YAlO (YAP (yttrium aluminum perovskite); yttrium aluminum perovskite phase), and YAlO (YAM (yttrium aluminum monoclinic); yttrium aluminum monoclinic phase), and combinations thereof. The terms "YAG" and "YAG phase" are used interchangeably herein.

[0055] As used herein, the term "sintered ceramic body" refers to a single layer or a multilayer body. In the case of a multilayer body, the term refers to a single, integral sintered ceramic article formed from co-compacting one or more powder mixtures by applying pressure and heat to form a single, dense, multilayer sintered ceramic body. The single multilayer sintered ceramic body can be machined into a single multilayer sintered ceramic component useful as a chamber component in plasma processing applications. As used herein, the terms "co-compacting" or "co-compaction" refer to a process in which at least two loose powder materials are placed in a die and subjected to pressure to form a powder compact. The powder compact does not contain binders, dispersants, and other similar organic materials required to form green bodies or compacts, or tapes, as is common in the art.

[0056] "Unitary" or "integral" means a single piece or component that is complete in itself without additional pieces, i.e., the component is one monolithic piece formed with another component as a unit.

[0057] As used herein, the term "substantially" is a descriptive term indicating approximation, meaning "to a great extent" or "to the majority, but not all, of what is specified," and is intended to avoid precise numerical boundaries for specified parameters.

[0058] As used herein, the term "sintered ceramic component" or "multilayer sintered ceramic component" refers to a single layer sintered ceramic body, a multilayer sintered ceramic body, or a corrosion-resistant ceramic after a machining process that forms the ceramic into the specific shape of a desired component for use in the semiconductor processing chambers disclosed herein.

[0059] As used herein, the term "powder mixture" means two or more starting powders mixed together prior to the sintering process, which are then formed into at least one layer of a multilayer sintered ceramic body.

[0060] The term "annealing" as applied to ceramic heat treatment is understood herein to mean a heat treatment performed in air on the disclosed multilayer sintered ceramic bodies to relieve stress and / or normalize stoichiometry.

[0061] As used herein, the term "tool set" may include at least one die and at least two punches. When fully assembled, the toolset defines a volume for placing a powder mixture as disclosed.

[0062] 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.

[0063] As used herein, a "solid solution" is defined as a mixture of different elements that share the same crystal lattice structure. The mixture within the lattice may be substitutional, where atoms from one starting crystal substitute for atoms from another starting crystal, or interstitial, where atoms occupy normally vacant positions in the lattice.

[0064] As used herein, the term "nano powder" refers to a powder containing 20m 2 / g.

[0065] 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.

[0066] 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 fired powder mixture, or a sintered region or portion.

[0067] As used herein, "ambient temperature" refers to a temperature range of about 22°C to 25°C.

[0068] As used herein, the term "purity" refers to the absence of various contaminants in a) the starting materials from which the powder mixture may be formed, b) the processed powder mixture (or fired powder mixture), and c) the multilayer sintered ceramic body or component disclosed herein. Higher purities (approaching 100%) refer to materials that are essentially free of, or have very small amounts of, contaminants or impurities, and that substantially comprise the material composition present in the starting powders disclosed.

[0069] As used herein, the term "impurities" refers to compounds / contaminants present in a powder or sintered ceramic other than the intended compound itself. Impurities may be present in the starting powder, the powder mixture, the processed powder mixture, and the sintered ceramic body. ICPMS techniques were used to determine the impurity content of the powders, powder mixtures, and the first and second layers of the sintered bodies disclosed herein.

[0070] As used herein, the term "dopant" refers to a substance added to a bulk material to impart desired properties to the ceramic material (e.g., to alter electrical properties). Typically, dopants, when used, are present in low concentrations, i.e., greater than 0.002% to less than 0.05% by weight.

[0071] Impurities differ from dopants in that dopants, as defined herein, are compounds that are intentionally added to a starting powder or powder mixture to obtain particular electrical, mechanical, optical, or other properties, such as, for example, modifying grain size in a multilayer sintered ceramic body.

[0072] As used herein, the term "sintering aid" refers to compounds such as silica (SiO), lithia (LiO), lithium fluoride (LiF), magnesia (MgO), and / or calcia (CaO) that increase densification during the sintering process, thereby reducing porosity. Hf and Y, to the extent present in the starting powder and remaining in the sintered ceramic, do not constitute sintering aids, impurities, or dopants as defined herein.

[0073] As used herein, the terms "approximately" and "about" when used in connection with numbers or features disclosed herein allow for a variance of plus or minus 10%.

[0074] The following detailed description assumes that the present disclosure is practiced in an apparatus such as an etch chamber or deposition chamber required as part of the fabrication of devices on a semiconductor wafer substrate. However, the present disclosure is not so limited. Workpieces can be of various shapes, sizes, and materials. In addition to semiconductor wafer processing, other workpieces that can utilize the present invention include various articles such as inorganic circuit boards with fine feature sizes, magnetic recording media, magnetic recording sensors, mirrors, optical elements, micromechanical devices, and the like.

[0075] During semiconductor device processing, corrosion-resistant parts or chamber components are used in etch chambers and are exposed to harsh corrosive environments that cause particle release into the etch chamber, resulting in yield loss due to wafer-level contamination. The sintered ceramic bodies and related components disclosed herein offer improved plasma etch resistance and enhanced ability to be cleaned in semiconductor processing chambers due to certain material properties and characteristics described below.

[0076] YAG

[0077] In some embodiments, provided herein is a sintered ceramic body comprising at least one layer comprising 90% to 99.8% by volume polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconium, wherein the at least one layer comprises at least one surface, and wherein the at least one surface contains pores, and the pores Pore ​​diameter not exceeding 5 μm death , having a maximum pore diameter of 1.5 μm for at least 95% of the pores death At least one surface exhibits an L* value of 50 to 77 and an a* value of 6 to 12, and at least one layer has a thickness of 500 μm to 2 cm, and the L* and a* values Coefficient of variation is less than 10% over at least one surface be Disclosed is a sintered ceramic body. In embodiments, the sintered ceramic body has a volume porosity of 0.1 to 4%, calculated from density measurements made in accordance with ASTM B962-17.

[0078] The sintered ceramic body includes at least one layer, and thus in some embodiments, is a single-layer sintered ceramic body comprising 90% to 99.8% by volume of polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm of zirconium, and having the properties disclosed herein. In other embodiments, the sintered ceramic body is a multilayer sintered ceramic body comprising at least one layer comprising 90% to 99.8% by volume of polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm of zirconium, and having the properties disclosed herein. In multilayer embodiments, the at least one layer comprising 90% to 99.8% by volume of polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm of zirconium, and having the properties disclosed herein, is preferably an outer layer and therefore may be the surface ultimately exposed to plasma in a plasma processing chamber during use. The second layer may be any suitable material, such as, for example, zirconia-toughened alumina or yttrium oxide.

[0079] In some embodiments, a sintered ceramic body, through the use of the materials and methods disclosed herein, includes at least one layer containing polycrystalline YAG having a cubic crystal structure in an amount of 90-99.6 volume %, preferably 90-99.4 volume %, preferably 95-99.6 volume %, preferably 95-99.4 volume %. In certain embodiments, the sintered ceramic body disclosed herein can contain 95-99.6 volume % YAG in the cubic crystal phase and 0.01-5 volume % aluminum oxide phase. The volume values ​​for the cubic crystal phase of YAG disclosed herein exclude any Al2O3 and zirconium-containing compounds. Embodiments of the sintered ceramic bodies disclosed herein are polycrystalline; therefore, the sintered ceramic body can include, but is not limited to, two or more crystal types. The sintered ceramic body may contain volume porosity in an amount of 0.1-4%, preferably 0.1-3%, preferably 0.1-2%, preferably 0.1-1%, preferably 0.1-0.5%, where volume porosity is calculated from density measurements made according to ASTM B962-17 or ASTM B311-17 if the porosity is less than 2%.

[0080] In another embodiment, the composition YAlO containing 90-99.8% by volume of a cubic crystal structure is used herein. 12 Disclosed is a sintered ceramic body comprising at least one layer comprising yttrium aluminum garnet (YAG) and aluminum oxide in an amount of 0.2-10% by volume, preferably 0.2-8% by volume, preferably 0.2-5% by volume, preferably 0.2-3% by volume, preferably 0.2-2% by volume, preferably 0.2-1% by volume.

[0081] In embodiments, at least one layer of the sintered ceramic body comprises at least one form of polycrystalline yttrium aluminum oxide in an amount of 70-100% by volume as determined by X-ray diffraction, a volume porosity of less than 0.1-5% as calculated from density measurements made in accordance with ASTM B962-17, a purity of greater than 99.99% as measured by ICPMS techniques, and a hardness of at least 1200 HV as measured in accordance with ASTM standard C1327. In embodiments, at least one layer of the sintered ceramic body comprises at least one polycrystalline yttrium aluminum oxide phase or combination of yttrium aluminum oxide phases, and in certain embodiments, yttrium aluminum garnet YAlO. 12 (YAG) phase, yttrium aluminum perovskite YAlO3 (YAP), and yttrium aluminum monoclinic Y4Al2O9 (YAM), and combinations thereof. In a preferred embodiment, the sintered ceramic body comprises 90% to 99.8% by volume polycrystalline yttrium aluminum garnet (YAG).

[0082] In some embodiments, at least one layer of a sintered ceramic body disclosed herein may comprise about 100% single crystalline phase of any one of the yttrium aluminum oxides YAG, YAP, or YAM. In other embodiments, the sintered ceramic body may comprise a matrix or composite structure of two or more discrete or continuous phases of the yttrium aluminum oxides disclosed herein. In further embodiments, the sintered ceramic body may comprise a minority phase of aluminum oxide and / or yttrium oxide with a majority of any one or combination of yttrium aluminum oxides YAG, YAP, and YAM.

[0083] For reference, Figure 1 shows a binary phase diagram for yttrium oxide / aluminum oxide. The horizontal axis corresponds to the mixture ratio (mol %) of yttria and alumina, and the vertical axis corresponds to temperature (°C). The left side of the horizontal axis corresponds to 100% alumina, and the right side corresponds to 100% yttria. The phase diagram in Figure 1 shows the regions where the yttrium aluminum oxide phases of YAG, YAP, and YAM form, as well as the molar composition and temperature conditions required to produce these forms. The formation of YAG may require precise batching and careful processing of powders to maintain stoichiometry and thus form a sintered ceramic body containing phase-pure YAG: 37.5 mol % yttrium oxide and 62.5 mol % aluminum oxide.

[0084] color

[0085] At least one layer of the sintered ceramic body disclosed herein contains 15 ppm to 500 ppm zirconium as a dopant and has at least one surface that exhibits an L* value of 50 to 77, an a* value of 6 to 12, and a b* value of 3 to 6 upon exposure to UV radiation. While not intending to be bound by any particular theory, it is believed that the YAG phase provides a host matrix into which the zirconium atoms infiltrate as a solid solution. Therefore, the upper limit of zirconium is the amount at which the zirconium no longer dissolves and forms a separate phase. Zirconium at the lower end of the range is preferably sufficient to impart a uniform red color to the YAG matrix upon exposure of at least one surface to UV radiation. The purpose of the added (i.e., doped) zirconium is to affect a uniform color change to red upon exposure of the sintered ceramic body to UV radiation, as described in more detail below. In embodiments, zirconium may be present in amounts from 15 ppm to 500 ppm, from 15 ppm to 100 ppm, from 15 ppm to 250 ppm, from 50 ppm to 250 ppm, from 50 ppm to 225 ppm, from 50 ppm to 200 ppm, from 50 ppm to 175 ppm, from 50 ppm to 150 ppm, from 50 ppm to 150 ppm, from 50 ppm to 125 ppm, from 50 ppm to 100 ppm, and from 50 ppm to 75 ppm.

[0086] The zirconium in the amounts mentioned above can be added as the oxide, chloride, nitrate, or any other counterion. Preferably, the zirconium is added as the oxide.

[0087] "Color" is described using the 1976 CIELAB color space (standard ISO 11664-4 defined by the International Commission on Illumination), which converts color into a lightness / darkness variable, L*, where absolute black is 0 and perfect white is 100, and other parameters, a* and b*, that describe the hue of an object. Typically, an object with an L* greater than 65 and less than 82, and absolute values ​​of a* and b* less than 5, is considered white. Uniformity and lightness may be assessed visually by eye, or preferably measured using commercially available equipment, such as, as one non-limiting example, the FRU WR-18 colorimeter, which uses the CIELAB L*a*b* scale. CIELAB L*a*b* values ​​are also referred to interchangeably herein as CIE Lab values ​​or L*, a*, b* values. The "a*" value refers to the red-green coordinate in a particular transformed color space and is commonly used as the difference in "a*" between the test sample and a standard reference color. When "a*" is positive, there is more red than green. When "a*" is negative, there is more green than red. The value of a* is usually used with b* as part of the chromaticity or chromaticity color difference. The value of "b*" refers to the yellow-blue coordinate in a particular color space and is commonly used as the difference in "b*" between a test sample and a standard reference color, usually used with "a*" or as part of the chromaticity difference. Generally, when "b*" is positive, there is more yellow than blue. When "b*" is negative, there is more blue than yellow.

[0088] At least one layer of the sintered ceramic bodies disclosed herein has at least one surface that, upon exposure to UV radiation, exhibits an L* value of 50 to 77, in some embodiments 50 to 60, an a* value of 6 to 12, and a b* value of 3 to 6. The "color" produced upon exposure to UV radiation exhibits a significant decrease in L* and a* across at least one surface. Coefficient of variation of is 10% or less, in some embodiments 3.0% or less, and in other embodiments 1.5% or less. can be , b* Coefficient of variation of is 15% or less, in some embodiments 7% or less, preferably 3% or less. be In one embodiment, the thickness of L* is uniform across at least one surface. Coefficient of variation is less than 3% can be, a* Coefficient of variation is less than 9% be Tables 1 and 2 show the results of a 22 inch (558.8 mm) (2,452 cm) zirconia reinforced aluminum tube made according to the process disclosed herein, which had a non-uniform distribution of ppm of zirconium as a result of migration of zirconium from the underlayer. 2 1 shows the difference in color uniformity of a 22-inch YAG coupon (Table 1) with 50 ppm doped zirconium made according to the processes disclosed herein versus a 22-inch YAG coupon with 50 ppm doped zirconium. In other words, both the samples in Table 1 and Table 2 were two-layer sintered ceramic bodies, each having a zirconia-reinforced aluminum substrate layer and a top layer containing YAG, but the sample in Table 1 included a YAG layer that was intentionally doped with 50 ppm zirconium, while the YAG layer of the sample in Table 2 was not doped with zirconium but had some zirconium due to migration during the manufacturing process. Color uniformity is important not only for the perception of chemical and physical uniformity, but also for emissivity uniformity, since darker areas absorb more heat than lighter areas, causing hot spots that can form cracks during use. [Table 1] [Table 2]

[0089] The relative density of the YAG layer of the sample in Table 1 was 99.9%, and the relative density of the YAG layer of the sample in Table 2 was 99.8%, so the YAG layer of the sample in Table 2 had a higher porosity than the YAG layer of the sample in Table 1.

[0090] Porosity and Density

[0091] At least one layer of the sintered ceramic bodies disclosed herein is highly dense and correspondingly has a very small pore profile such that at least one surface contains pores having a pore size no greater than 5 μm. In some embodiments, the pores have a maximum pore size of 1.5 μm for at least 95% of the pores.

[0092] To evaluate the grain size of the at least one first layer containing polycrystalline YAG, linear intercept grain size measurements were performed according to the Heyn Linear Intercept Procedure described in ASTM Standard E1 12-2010, "Standard Test Method for Determining Average Grain Size." Grain size measurements were performed (as described in Table 3), and an average grain size of 1.1 to 6.3 μm was measured over 25 replicates. Maximum and minimum grain sizes of 2 to 7.7 μm were also measured on the surface of the at least one first layer containing YAG. A single multilayer sintered ceramic body can have a surface with a maximum grain size of about 8 μm or less, preferably a maximum grain size of 6 μm or less, for example. In embodiments, a single multilayer sintered ceramic body can have a surface having an average grain size of 0.4 to 6.5 μm, preferably 0.4 to 5 μm, preferably 0.4 to 3 μm, preferably 0.8 to 6.5 μm, preferably 0.8 to 5 μm, preferably 0.8 to 3 μm, preferably 1 to 7 μm, preferably 1 to 6.5 μm. [Table 3]

[0093] Density measurements were made using the Archimedes buoyancy method according to ASTM B962-17 and ASTM B311-17 (when porosity levels are 2% or less). Reported density values ​​and standard deviations are averages over five or more measurements. A commercially available single crystal sample of YAG was measured for density using the method disclosed herein. A commercially available single crystal sample of bulk YAG was measured for density using the method disclosed herein. An Archimedes density of 4.56 g / cc was obtained over five measurements, and this value is the theoretical density of YAG used herein. Sintered ceramic bodies comprising at least one layer of phase-pure YAG as disclosed in embodiments herein and further phase-pure YAG comprising up to 1% excess alumina by weight can have theoretical densities of YAG of, for example, 4.374-4.556 g / cc, 4.419-4.556 g / cc, 4.465-4.556 g / cc, 4.510-4.556 g / cc, and 4.533-4.556 g / cc, or percentages of 96-99.999%, 97-99.999%, 98-99.999%, 99-99.999%, and 99.5-99.999%. The corresponding volumetric porosity (Vp), calculated from density measurements performed as disclosed herein, can be less than 0.010-5%, 0.010-4%, 0.010-3%, 0.010-3%, 0.010-2%, or 0.010-1%, preferably less than 1%, and preferably less than 0.5%. In an embodiment in which the ceramic sintered body includes at least one second layer containing approximately 16 volume percent stabilized zirconia and / or partially stabilized zirconia (and the remainder alumina), the density was measured under similar conditions and calculated to be approximately 4.32 g / cc. Using the volumetric rule of mixtures to calculate the theoretical density of ZTA containing approximately 16 volume percent zirconia, the measured density of 4.32 g / cc was adopted as the theoretical density of the at least one second layer containing approximately 16 volume percent zirconia. Thus, at least one second layer of a multilayer sintered ceramic body comprising about 16 volume percent zirconia has a percent theoretical density of 99-100%, preferably 99.5-100%, preferably about 100%.According to this embodiment, the disclosed multilayer sintered ceramic body has a % theoretical density (also referred to as relative density (RD)) that is greater than 99%, preferably 99-100%, preferably 99.5-100%, preferably about 100% of the theoretical density of a single multilayer sintered ceramic body comprising at least one first and second layer.

[0094] The relative density (RD) of a given material is defined as the ratio of the measured density of a sample to the reported theoretical density of the same material, as shown in the following equation: Volume porosity (Vp) is calculated from the density measurements as follows:

number

[0095] These density, purity, and porosity levels can provide improved resistance to the erosion and corrosion effects resulting from plasma etching and deposition processes. The disclosed methods and materials are particularly useful for preparing sintered ceramic bodies with large dimensions, e.g., maximum dimensions of 200 to about 625 mm. The high density and resulting high mechanical strength of the sintered ceramic bodies also provide improved handleability, especially at large dimensions. Successful fabrication of sintered yttrium aluminum oxide bodies, particularly those formed from phase-pure YAG in the ranges disclosed herein across their longest dimension (about 200 to about 625 mm), can be enabled by controlling the variation in density across at least one longest dimension. An average density of 96% or greater is desirable, with density variations of 0.2-5% or less, preferably 4% or less, preferably 3% or less, preferably 2% or less, preferably 1% or less, measured across the largest dimension, which may be, for example, 100-625 mm, preferably 100-622 mm, preferably 100-575 mm, preferably 200-625 mm, preferably 200-510 mm, preferably 400-625 mm, preferably 500-625 mm. Low densities below 95% of the theoretical density of YAG can have lower strength and thereby higher porosity above 5%, which can result in breakage and poor handleability.

[0096] In addition to high density, variations in density across the largest dimension of the disclosed ceramic sintered bodies can affect their ability to be handled, machined, and used as ceramic sintered components, especially at larger (>100 mm) dimensions. Density was measured across the largest dimension of some examples of the ceramic sintered bodies disclosed herein.

[0097] In addition to high density, high hardness values ​​can further provide improved resistance to erosion during use as plasma chamber components. Therefore, Vickers hardness measurements were performed 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 Micro Hardness Tester Model VH1202. For the ceramic sintered bodies disclosed herein, hardness values ​​of at least 1200 HV, preferably at least 1400 HV, preferably at least 1800 HV, preferably at least 2000 HV, 1300-1600 HV, 1300-1500 HV, 1300-1450 HV, 1300-1400 HV, 1400-1600 HV, 1450-1600 HV, and 1450-1550 HV can be obtained. Measurements were obtained using the Vickers hardness method known in the art and converted to SI units of GPa. For the ceramic sintered bodies disclosed herein, hardness values ​​of 12.75-15.69 GPa, 12.75-14.71 GPa, 12.75-14.22 GPa, 12.75-13.73 GPa, 13.73-15.69 GPa, and 14.22-15.69 GPa, preferably 14.22-15.20 GPa, can be obtained. These high hardness values ​​can contribute to improved resistance to ion bombardment during semiconductor etching processes and reduced erosion during use, providing extended life when the ceramic sintered bodies are machined into ceramic sintered components with fine-scale features.

[0098] In one embodiment, the sintered ceramic bodies disclosed herein have an average hardness of 13.0 to 15.0 GPa, measured according to ASTM standard C1327 for eight samples using an applied load of 0.2 kgf. In another embodiment, the sintered ceramic bodies disclosed herein have an average hardness of about 13.5 to 14.5 GPa, measured according to ASTM standard C1327 for eight samples using an applied load of 0.2 kgf.

[0099] Mechanical strength properties are known to improve with decreasing grain size. To evaluate grain size, linear intercept grain size measurements were performed according to the Heyn Linear Intercept Procedure described in ASTM Standard E1 12-2010, "Standard Test Method for Determining Average Grain Size." Grain size can also be measured by SEM. To meet the high bending strength and rigidity requirements for use in reaction chambers as large components of 200 to 625 mm, the ceramic sintered body can have a fine grain size, for example, a maximum grain size of about 10 μm or less, preferably a maximum grain size of 8 μm or less, an average grain size of preferably 5 μm or less, an average grain size of preferably 3 μm or less, preferably 2 μm or less, preferably 1.5 μm or less, preferably 1.0 μm or less, and a grain size of preferably 0.5 to 8 μm, preferably 1 to 5 μm.

[0100] At least one layer comprising 90% to 99.8% by volume polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconium 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 5 to 30 ppm, preferably 5 to 20 ppm, based on the total mass of the at least one first layer comprising polycrystalline YAG and 15 ppm to 500 ppm zirconium, as measured using ICPMS techniques. The total impurity content disclosed herein does not include Si in the form of silica.

[0101] The detection limits using the ICP-MS methods disclosed herein to identify the presence of lighter elements are higher than the reporting limits for heavier elements. In other words, heavier elements, such as Sc and above, are detected with a higher accuracy, e.g., an accuracy of 0.06 ppm, than lighter elements, such as Li to Al (which are detected with an accuracy of, e.g., 0.7 ppm). Thus, the impurity content of powders containing lighter elements, such as Li to Al, can be determined to about 0.7 ppm or better, and the impurity content of heavier elements, from Sc (scandium) to U (uranium), can be determined to about 0.06 ppm or better. Using the ICP-MS methods disclosed herein, silica 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 or better. Iron can be detected with an accuracy of as low as 0.14 ppm.

[0102] 1. A sintered ceramic body comprising at least one layer comprising 90% to 99.8% by volume polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconium, as disclosed herein, wherein the at least one layer comprises at least one surface, and contains pores, and the pores Pore ​​diameter not exceeding 5 μm death , having a maximum pore diameter of 1.5 μm for at least 95% of the pores death At least one surface exhibits an L* value of 50 to 77 and an a* value of 6 to 12, and at least one layer has a thickness of 500 μm to 2 cm, and the values ​​of L* and a* are Coefficient of variation is less than 10% over at least one surface be The sintered ceramic body can be a single layer sintered ceramic body or can be a layer of a multi-layer sintered ceramic body.

[0103] In the case of a multilayer sintered ceramic body including one or more additional layers, the one or more additional layers can be, for example, one or more of: (i) alumina including at least one of stabilized zirconia and partially stabilized zirconia; (ii) an additional YAG layer; (iii) yttria; and (iv) alumina.

[0104] In some embodiments, the at least one first layer comprising YAG may have a purity (excluding Al2O3 and zirconium-containing compounds) of 99.99% or greater, preferably 99.995% or greater, respectively, for a material having 100% purity, as measured using the ICPMS method disclosed herein.

[0105] The above-mentioned properties of the corrosion-resistant component formed from the sintered ceramic body are achieved by adjusting the purity of the yttrium oxide and aluminum oxide powders, the powder blending, the sintering of the powders, the pressure on the yttrium oxide and aluminum oxide powders, the temperature of the yttrium oxide and aluminum oxide powders, the duration of the sintering of the powders, the temperature of the sintered ceramic body / component during the optional annealing step, and the duration of the optional annealing step. The methods disclosed herein are suitable for producing sintered ceramic bodies, particularly large-sized sintered ceramic bodies, using a scalable manufacturing process.

[0106] Preparation method The preparation of sintered ceramic bodies disclosed herein can be achieved, for example, by the use of 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 techniques use direct current to heat an electrically conductive die configuration or tool set, thereby heating the material to be sintered. This heating regime allows for very high heating and cooling rates to be applied, enhancing densification mechanisms over diffusion mechanisms that promote grain growth, facilitating the preparation of sintered ceramic bodies with very fine grain sizes and transferring the intrinsic properties of the original powder to their near- or fully dense products. The DC pressure-assisted methods disclosed herein utilize continuous, preferably non-pulsed, direct current to heat the disclosed tool sets.

[0107] Provided herein is a method for preparing a sintered ceramic body as disclosed above, comprising at least one layer comprising 90 volume % to 99.8 volume % polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconium, wherein the at least one layer comprises at least one surface, and the at least one surface contains pores, and the pores Pore ​​diameter not exceeding 5 μm death , having a maximum pore diameter of 1.5 μm for at least 95% of the pores death At least one surface exhibits an L* value of 50 to 77 and an a* value of 6 to 12, and at least one layer has a thickness of 500 μm to 2 cm, and the values ​​of L* and a* are Coefficient of variation is less than 10% over at least one surface be A method for preparing a sintered ceramic body is disclosed, the method including: a) combining yttria powder, alumina powder, and a zirconium-containing powder providing 15 to 500 ppm zirconium to form a first powder mixture; b) firing the first powder mixture by applying heat to raise the temperature of the first powder mixture to a firing temperature and maintaining the firing temperature to form a first fired powder mixture; c) disposing the first fired powder mixture within a volume defined by a sintering apparatus toolset to form at least one layer of the first fired powder mixture and create a vacuum condition within the volume; and d) heating the first powder mixture to a sintering temperature to form a first fired powder mixture. a) applying pressure to at least one layer of the first fired powder mixture while heating to form a sintered ceramic body comprising at least one layer comprising 90 volume % to 99.8 volume % polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconium; b) reducing the temperature of the sintered ceramic body; and c) exposing the sintered ceramic body to UV radiation for a time period of 1 to 200 minutes, wherein the first fired powder mixture has a total impurity content of 150 ppm or less, and the yttria powder and alumina powder of step a) each have a total impurity content of about 18 ppm as measured in accordance with ASTM C1274. 2 / g or less, at least one layer containing 90 volume % to 99.8 volume % polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconium, at least one layer containing at least one surface, and at least one surface contains pores, and the pores Pore ​​diameter not exceeding 5 μm death , having a maximum pore diameter of 1.5 μm for at least 95% of the pores death At least one surface exhibits an L* value of 50 to 77 and an a* value of 6 to 12, and at least one layer has a thickness of 500 μm to 2 cm, and the L* and a* values Coefficient of variation is less than 10% over at least one surface be The following additional steps are optional: annealing the ceramic body by applying heat to raise the temperature of the ceramic body to reach an annealing temperature to form an annealed ceramic body; lowering the temperature of the annealed ceramic body; and machining the ceramic body or the annealed ceramic body to produce ceramic sintered components such as a dielectric window or RF window in an etching chamber, a focus ring, a nozzle or gas injector, a showerhead, a gas distribution plate, an etching chamber liner, a plasma source adapter, a gas inlet adapter, a diffuser, an electronic wafer chuck, a chuck, a puck, a mixing manifold, an ion suppressor element, a faceplate, an isolator, a spacer, and / or a guard ring.

[0108] The method disclosed herein involves the production of yttrium oxide (YO), aluminum oxide (AlO), and aluminium oxide (AlO) of the composition YAlO. 12 The present invention provides for the preparation of ceramic sintered bodies and components comprising yttrium aluminum garnet (YAG) of composition YAlO3, yttrium aluminum perovskite (YAP) of composition YAlO3, and yttrium aluminum monoclinic (YAM) of composition Y4Al2O9, as well as combinations thereof.

[0109] In embodiments, the methods disclosed herein provide for the preparation of a ceramic sintered body comprising YAG of garnet cubic crystal structure in an amount of 90-99.5% by volume of cubic crystal structure, preferably 90-99% by volume of cubic crystal structure, preferably 95-99.5% by volume of cubic crystal structure, preferably 95-99% by volume of cubic crystal structure. In alternative embodiments, an Al2O3 phase may be present in the YAG-containing ceramic sintered body in an amount of 0.1-5% by volume, 0.1-3% by volume, 0.1-2% by volume, 0.1-1% by volume, or preferably less than 1% by volume.

[0110] Using the materials and methods as disclosed herein, high densities, such as 96%, 98%, and 99.5% or more of the theoretical density for phase-pure YAG, can be achieved for the ceramic sintered bodies as disclosed without the use of sintering aids. Thus, in embodiments, ceramic sintered bodies comprising YAG are substantially free or free of sintering aids (other than zirconium compounds used as dopants as described herein).

[0111] In embodiments, ceramic sintered bodies containing 90% to 99.8% by volume polycrystalline YAG may contain excess yttria and / or alumina beyond the stoichiometric amount of YAG, which may remain from processing or may be intentionally added during powder batching and preparation. Thus, excess yttria and / or alumina, to the extent that it may remain in the ceramic sintered body, is not considered a dopant or sintering aid.

[0112] In embodiments, the disclosed process provides for the preparation of highly phase-pure YAG of greater than 99% by volume cubic crystal structure with high (>98%) density, high purity, and low porosity. In alternative embodiments, the disclosed process provides for the preparation of highly phase-pure YAG of greater than 95% by volume cubic crystal structure with a secondary crystalline phase of 5% or less by volume of alumina, the sintered body also having high density, high purity, and low porosity. In further embodiments, the disclosed process provides for the preparation of yttrium aluminum garnet, YAlO, having high purity, high density, and low porosity. 12 The present invention provides the preparation of mixed-phase and / or phase-pure ceramic sintered bodies of yttrium aluminum perovskite (YAG), yttrium aluminum perovskite YAlO (YAP), and / or yttrium aluminum monoclinic YAlO (YAM), and combinations thereof. The disclosed ceramic sintered bodies are particularly suitable for use in plasma processing equipment, such as semiconductor manufacturing equipment. Such parts or components can include, among other components, windows, nozzles, gas injectors, showerheads, (etch) chamber liners, mixing manifolds, wafer supports, electronic wafer chucks, and various rings, such as focus rings and guard rings.

[0113] Step a) of the method disclosed herein involves combining yttria powder, alumina powder, and a zirconium-containing powder providing 15 to 500 ppm zirconium to form a first powder mixture. The aluminum oxide and yttrium oxide starting powder materials for forming the corrosion-resistant ceramic sintered body and subsequent components are preferably high-purity commercially available powders. However, other oxide powders, such as those produced by chemical synthesis processes and related methods, may also be used. The d50 is defined as the median and represents the value above which half of the population lies and the other half lies below this point. Similarly, 90% of the distribution is below the d90, and 10% of the population is below the d10.

[0114] The d10 particle size of the yttrium oxide powder used as a starting material according to one embodiment of the present invention is preferably 1 to 7 μm, preferably 1 to 6 μm, preferably 1 to 5 μm, preferably 2 to 7 μm, preferably 3 to 7 μm, preferably 4 to 7 μm, preferably 5 to 7 μm.

[0115] The d50 particle size of the yttrium oxide powder used as starting material according to one embodiment of the present invention is preferably 3 to 11 μm, preferably 3 to 9.5 μm, preferably 3 to 8.5 μm, preferably 3 to 7.5 μm, preferably 4 to 11 μm, preferably 5 to 11 μm, preferably 6 to 11 μm, preferably 7 to 11 μm.

[0116] The d90 particle size of the yttrium oxide powder used as a starting material according to one embodiment of the present invention is preferably 6-20 μm, preferably 6-18 μm, preferably 6-16 μm, preferably 8-20 μm, preferably 10-20 μm, preferably 15-20 μm, preferably 8-18 μm, preferably 10-18 μm.

[0117] The yttrium oxide powder is preferably 0.75 to 12 m 2 / g, preferably 0.75 to 10m 2 / g, preferably 0.75 to 8m 2 / g, preferably 0.75 to 6m 2 / g, preferably 0.75 to 4m 2 / g, preferably 0.75 to 2m 2 / g, preferably 1 to 6m 2 / g, preferably 1 to 4 m 2 / g, preferably 2 to 10 m 2 / g, preferably 4 to 10 m 2 / g, preferably 6 to 10 m 2 / g, preferably 1 to 4 m 2 / g specific surface area (SSA).

[0118] 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%, more preferably greater than 99.9999%, which corresponds to an impurity level of 100 ppm or less, preferably 50 ppm or less, preferably 25 ppm or less, preferably 10 ppm or less, more preferably about 1 ppm, preferably between 1 and 100 ppm, preferably between 1 and 50 ppm, preferably between 1 and 25 ppm, preferably between 1 and 10 ppm, preferably between 1 and 5 ppm.

[0119] The d10 particle size of the aluminum oxide powder used as a starting material in one embodiment of the present invention is preferably 0.05 to 4 μm, preferably 0.05 to 3 μm, preferably 0.05 to 2 μm, preferably 0.05 to 1 μm, preferably 0.05 to 0.75 μm, preferably 0.05 to 0.5 μm, preferably 0.2 to 4 μm, preferably 0.2 to 3 μm, preferably 0.2 to 2 μm, preferably 0.2 to 1 μm, preferably 0.4 to 4 μm, preferably 0.4 to 3 μm, preferably 0.4 to 2 μm, preferably 0.4 to 1 μm, preferably 0.75 to 2 μm, preferably 0.75 to 3 μm, preferably 1 to 3 μm, preferably 2 to 3 μm.

[0120] The d50 particle size of the aluminum oxide powder used as a starting material according to one embodiment of the present invention is typically 0.15 to 8 μm, preferably 0.15 to 5 μm, preferably 0.15 to 3 μm, preferably 0.15 to 1 μm, preferably 0.15 to 0.5 μm, preferably 1 to 8 μm, preferably 1 to 6 μm, preferably 1 to 4 μm, preferably 2 to 6 μm, preferably 3 to 8 μm, preferably 4 to 8 μm, preferably 5 to 8 μm, preferably 3.5 to 6.5 μm.

[0121] The d90 particle size of the aluminum oxide powder used as starting material according to one embodiment of the present invention is 0.50 to 75 μm, preferably 0.35 to 10 μm, preferably 0.35 to 5 μm, preferably 0.35 to 3 μm, preferably 0.35 to 1 μm, preferably 0.35 to 0.75 μm, preferably 3 to 80 μm, preferably 3 to 60 μm, preferably 3 to 40 μm, preferably 3 to 20 μm, preferably 10 to 60 μm, preferably 10 to 40 μm, preferably 10 to 30 μm, preferably 10 to 20 μm, preferably 30 to 60 μm, preferably 15 to 60 μm, preferably 40 to 60 μm, preferably 6 to 15 μm.

[0122] Aluminum oxide powder is usually 3 to 18 m 2 / g, preferably 3 to 16 m 2 / g, preferably 3 to 14 m 2 / g, preferably 3 to 12 m 2 / g, preferably 3 to 10 m 2 / g, preferably 3 to 6 m 2 / g, preferably 6 to 18 m 2 / g, preferably 6 to 14 m 2 / g, preferably 8 to 18 m 2 / g, preferably 10 to 18 m 2 / g, preferably 8 to 10 m 2 / g, preferably 4 to 9 m 2 / g, preferably 5 to 10 m 2 / g, preferably 6 to 8 m 2 / g specific surface area.

[0123] The purity of the aluminum oxide starting material is typically greater than 99.99%, preferably greater than 99.995%, preferably greater than 99.999%, preferably greater than 99.9995%, as measured using ICPMS techniques. Correspondingly, the impurity content of the alumina powder can be 100 ppm or less, preferably 50 ppm or less, preferably 25 ppm or less, preferably 10 ppm or less, more preferably 5 ppm or less.

[0124] In embodiments, the aluminum oxide powder can comprise 80-100% by volume alpha alumina crystalline phase, preferably 90-100% by volume alpha alumina crystalline phase, preferably 95-100% by volume alpha alumina crystalline phase.

[0125] Table 4 lists the properties of the disclosed starting materials for forming sintered bodies containing YAG. The particle sizes of the starting powders, powder mixtures, and sintered powder mixtures were measured using a Horiba Model LA-960 Laser Scattering Particle Size Distribution Analyzer, which is capable of measuring particle sizes from 10 nm to 5 mm. The specific surface areas of the starting powders, powder mixtures, and sintered powder mixtures ranged from 0.01 to 2000 m for most samples. 2 The measurements were performed using a Horiba BET Surface Area Analyzer model SA-9601, which is capable of measuring specific surface areas of 10% or less over a range of 10% / g. [Table 4]

[0126] A dopant, preferably in powder form, including a zirconium compound is added to the yttria and alumina powder. The zirconium compound may include, for example, zirconium oxide (zirconia), zirconium chloride, zirconium nitrate, or any other counterion to zirconium. In a preferred embodiment, the zirconium is added as zirconia oxide, which may be stabilized with, for example, yttria. The amount of dopant zirconium compound should be sufficient to provide zirconium in amounts of 15-500 ppm, 15 ppm-350 ppm, 15 ppm-250 ppm, 15 ppm-200 ppm, 15 ppm-100 ppm, 15 ppm-50 ppm, 50 ppm-225 ppm, 50 ppm-200 ppm, 50 ppm-175 ppm, 50 ppm-150 ppm, 50 ppm-150 ppm, 50 ppm-125 ppm, 50 ppm-100 ppm, and 50 ppm-75 ppm. As a guide, Table 5 provides the amount of zirconia dopant required to achieve a specific target concentration of zirconium. [Table 5]

[0127] For embodiments in which the zirconium dopant compound is zirconium oxide, the zirconia powder may have a particle size distribution with a d10 of 0.08-0.20 μm, a d50 of 0.3-0.7 μm, and a d90 of 0.9-5 μm. The zirconium oxide powder used as a starting material for a mixture according to one embodiment of the present invention may have an average particle size of 0.3-1 μm.

[0128] Zirconia powders typically have a particle size of 1 to 16 m as measured according to ASTM C1274. 2 / g, preferably 2 to 14 m 2 / g, preferably 4 to 12 m 2 / g, more preferably 5 to 9 m 2 / g specific surface area (SSA).

[0129] The purity of the zirconia powder starting material is preferably greater than 99.8%, preferably greater than 99.9%, preferably greater than 99.95%, preferably greater than 99.975%, preferably greater than 99.99%, preferably greater than 99.995%. This corresponds to a total impurity content of 2000 μm or less, preferably 1000 ppm or less, preferably 500 ppm or less, preferably 250 ppm or less, preferably 100 ppm or less, preferably 50 ppm or less, preferably 25-150 ppm, as measured using the ICPMS (inductively coupled plasma mass spectrometry) method disclosed herein. The zirconia used in the embodiments disclosed herein typically contains a small amount of Hf, about 2-5 wt.%, as is common in many commercially available zirconia powders.

[0130] In other embodiments, the powder mixture is sintered at least one first layer of a multi-layer sintered ceramic body comprising YAG by the in situ reactive phase sintering process disclosed herein. 2 It may be preferable to avoid the inclusion of YAG phases having a specific surface area of ​​1 / g or greater. All purity measurements disclosed herein were measured above the reporting limit for the particular element and were completed using an Agilent ICPMS, 7900 ICP-MS Model G8403, quadrupole mass spectrometry system. The detection limits using the ICP-MS methods disclosed herein to identify the presence of lighter elements are higher than the reporting limits for heavier elements.

[0131] In embodiments, a sintered ceramic body containing 90 vol% to 99.8 vol% polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconia can be formed from a stoichiometric powder mixture of 37.5 mol% yttrium oxide and 62.5 mol% aluminum oxide. 12"The work reported in Patel et al., 2008, Appl. Phys. Lett. 93, 191902 (2008) showed that the width of the phase domains can have a variance of 0.1 mol% or less. Thus, deviations of 0.1 mol% or less from that of stoichiometric YAG (37.5% alumina / 62.5% yttria) can result in the formation of phase-pure yttrium aluminum garnet oxide. Thus, in embodiments, amounts greater than 99% by volume of yttrium aluminum garnet (YAG) garnet cubic phase (YAlO 12 A ceramic sintered body comprising yttria may be formed from starting powders combined into a powder mixture in the ratio of 37.4-37.6 mol % yttrium oxide and 62.6 and 62.4 mol % aluminum oxide. By weight, the powder mixture may be formed from approximately 42.9-43.4% alumina and 57.1-56.6% yttria.

[0132] Combining the above-described starting powders including yttrium oxide, aluminum oxide, and zirconium compound dopants to form the first powder mixture can be carried out using powder preparation techniques such as wet or dry ball (axial rotation) milling, wet or dry tumbling (end-over-end or vertical) mixing, and combinations thereof.

[0133] To maintain the purity of the starting powder during mixing, high-purity (>99.99%) alumina media can be used to achieve ball milling or end-over-end tumbling mixing under dry conditions. The high-purity alumina media used herein was tested using ICPMS and found to have a purity of 99.997%. The media loading for dry ball or tumbling mixing can vary from large media elements (approximately 30 mm) to approximately 50% media loading by powder weight. Dry milling or mixing can be performed using an RPM of 50-200 RPM, preferably 75-150 RPM, and preferably 100-125 RPM, for 12-48 hours, preferably 16-48 hours, and preferably 24-48 hours.

[0134] Wet ball milling or tumbling mixing can be performed by suspending the starting powders in various solvents, such as ethanol, methanol, and other alcohols, and / or water, to form a slurry. The slurry may be formed so that the powder loading during milling or mixing is 5-50% by powder weight, preferably 10-40% by powder weight, and preferably 20-40% by powder weight. Wet mixing or milling improves powder dispersion through increased mobility, resulting in fine-scale uniform mixing prior to heat treatment or calcination. In certain embodiments, a dispersant can be optionally added to the slurry using any number of commercially available dispersants, such as polymethyl methacrylate (PMMA) and polyvinyl pyrrolidone (PVP). The dispersant can optionally be added in an amount of 0 (no dispersant) to 0.2% by powder weight, preferably 0-0.1% by powder weight. Media loading can vary from no media used during milling to media loadings of 50% or more by powder weight, preferably 40-100% by powder weight, preferably 60-100% by powder weight, and preferably 50-80% by powder weight. Wet ball milling or tumbling can be carried out for 8-48 hours, preferably 12-48 hours, preferably 16-48 hours, preferably 8-36 hours, preferably 8-24 hours, and preferably 8-12 hours. Ball milling can use RPMs of 50-200 RPM, preferably 75-150 RPM, and preferably 100-125 RPM, for vessels with diameters up to about 200 mm. End-over-end tumbling can be carried out at 10-30 rpm, preferably about 20 RPM.

[0135] Jet milling processes, known to those skilled in the art, can also be used to thoroughly mix powders to form powders, powder mixtures, or calcined powder mixtures with narrow particle size distributions. Jet milling uses high-velocity jets of either inert gas or air to collide particles of the starting powder and / or powder mixture and / or calcined powder mixture without the use of milling or mixing media, thus preserving the initial purity of the milled powder. The starting powders, powder mixtures, and / or calcined powder mixtures disclosed herein may be subjected to jet milling at a pressure of approximately 100 psi, either alone or in combination with any or all of the powder milling / mixing processes disclosed herein. After jet milling, the powder or powder mixture may optionally be sieved and blended using any number of meshes, e.g., with openings of 45 to 400 μm, in any number of repetitions or in any order.

[0136] The use of wet ball milling, tumbling mixing, and / or jet milling are high-energy processes that can break down fine particles and agglomerates, improve dispersion through increased particle mobility, provide fine-scale mixing, and provide a homogeneous powder mixture before firing. Additional powder preparation procedures such as attrition milling, high-shear mixing, planetary milling, and other procedures known to those skilled in the art can also be applied. The slurry may be dried by rotary evaporation. In other embodiments, the slurry may be dried using spray drying techniques known in the art. Before or after drying, the powder mixture can be sieved, for example, using a mesh with openings of 35 to 75 μm. The aforementioned powder preparation techniques may be used alone or in any combination thereof.

[0137] After drying, the surface area of ​​the powder mixture of step a) is between 2 and 17 m 2 / g, 2-14m 2 / g, 2-12m 2 / g, 2-10m 2 / g, 4-17m 2 / g, 6-17m 2 / g, 8-17m 2 / g, 10-17m 2 / g, 4-12m 2 / g, 4-10m 2 / g, and 5-8m 2 / g.

[0138] At this point in the process, if a multi-layer sintered ceramic body is to be formed, a second powder mixture may be formed. The second powder mixture may include, for example, combining an alumina powder with a zirconia powder, including at least one of a partially stabilized zirconia powder and a stabilized zirconia powder, to create the second powder mixture described in U.S. Provisional Patent Application No. 63 / 216,356, filed June 29, 2021, the contents of which are incorporated herein by reference.

[0139] Step b) of the methods disclosed herein involves heating the first powder mixture (and any additional powder mixtures) to a calcination temperature and maintaining the calcination temperature for a duration to form a first calcined powder mixture (also referred to herein as a "calcined powder mixture"). The calcination disclosed herein may be carried out under ambient pressure in an oxygen-containing environment, although other pressures and calcination environments may be used.

[0140] Calcination may be performed to remove moisture and ensure a uniform surface condition of the powder mixture before sintering. In certain embodiments, calcination may be performed to reduce the surface area. In other embodiments, calcination does not cause a reduction in the surface area of ​​the starting powder.

[0141] The calcination in the heat treatment step can be carried out at a temperature of 600°C to 1100°C, preferably 600 to 1000°C, preferably 600 to 900°C, preferably 700 to 1100°C, preferably 800 to 1100°C, preferably 800 to 1000°C, preferably 850 to 950°C. The calcination can be carried out in an oxygen-containing environment for 4 to 12 hours, preferably 4 to 10 hours, preferably 4 to 8 hours, preferably 6 to 12 hours, preferably 4 to 6 hours. After calcination, the calcined powder mixture can be sieved, for example, through a mesh screen having openings of 45 to 400 μm, and / or tumbled and / or blended according to known methods to form a calcined powder mixture.

[0142] The calcined powder mixture for forming the YAG phase may have a d10 particle size of preferably 0.06-4 μm, preferably 0.08-4 μm, preferably 0.1-4 μm, preferably 0.2-4 μm, preferably 0.3-4 μm, preferably 0.4-4 μm, preferably 0.08-3 μm, preferably 0.08-2 μm, preferably 0.08-1 μm, preferably 0.5-3 μm, preferably 1-2 μm, preferably 1-3 μm.

[0143] The d50 particle size of the calcined powder mixture can vary from 0.7 to 50 μm, preferably from 1 to 40 μm, preferably from 1 to 30 μm, preferably from 1 to 20 μm, preferably from 1 to 10 μm, preferably from 1 to 5 μm, preferably from 5 to 50 μm, preferably from 10 to 50 μm, preferably from 20 to 50 μm, preferably from 30 to 50 μm, preferably from 3 to 8 μm, preferably from 5 to 10 μm, preferably from 6 to 15 μm.

[0144] The d90 particle size of the calcined powder mixture may be preferably 10 to 350 μm, preferably 10 to 300 μm, preferably 10 to 250 μm, preferably 10 to 200 μm, preferably 10 to 175 μm, preferably 10 to 150 μm, preferably 10 to 100 μm, preferably 10 to 75 μm, preferably 10 to 50 μm, preferably 10 to 40 μm, preferably 10 to 30 μm, preferably 15 to 45 μm, preferably 20 to 40 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.

[0145] In certain embodiments, the firing conditions disclosed herein may result in the formation of one or more crystalline phases of YAP, YAM, and YAG, and combinations thereof, and / or aggregation of the powder mixture, resulting in a wide range of particle or aggregate sizes. Thus, in some embodiments, the particle sizes referred to herein may include single particles, while in other embodiments, the particle sizes referred to herein may include aggregates containing two or more particles or aggregates of multiple particles that can be measured as a larger single particle using the laser particle size detection methods disclosed herein. Particles containing either or both single particles or aggregates of multiple particles may comprise at least one crystalline phase selected from the group consisting of yttrium oxide, aluminum oxide, yttrium aluminum perovskite (YAP), yttrium aluminum monoclinic (YAM), and YAG (garnet) phases, and combinations thereof. In other embodiments, the lower temperature firing conditions disclosed herein may not affect the particle size distribution for the starting material, and the particle size distribution may be in the same range or similar to that of the starting powder material. Lot-to-lot variations and sustained heat transfer during firing can also contribute to the broadening of the particle size distribution. The starting powders, powder mixtures, and / or fired powder mixtures disclosed herein can be subjected to any one or combination of the mixing / milling processes disclosed herein. Thus, a wide range of particle size distributions can result from the firing conditions and processes as disclosed herein.

[0146] The calcined powder mixture is approximately 1 m2, measured in accordance with ASTM C1274. 2 / g ~ approx. 18m 2 / g, preferably 1m 2 / g ~ approx. 14m 2 / g, preferably about 1 m 2 / g~about 10m 2 / g, preferably about 1 m 2 / g~about 8m 2 / g, preferably about 2m 2 / g ~ approx. 18m 2 / g, preferably about 2m 2 / g ~ approx. 14m 2 / g, preferably about 2m 2 / g~about 10m2 / g, preferably about 3m2 / g to about 9m2 / g, preferably about 3m 2 / g~about 6m 2 / g specific surface area (SSA).

[0147] The calcined powder mixture may have a total impurity content of 5 to 200 ppm, preferably 5 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 to 100 ppm, preferably 10 to 80 ppm, preferably 10 to 60 ppm, preferably 10 to 40 ppm, preferably 20 to 80 ppm, preferably 30 to 60 ppm, based on the mass of the calcined powder mixture.

[0148] Table 6 shows the ICPMS purity results of a typical fired powder mixture before being formed into a polycrystalline YAG layer according to the present disclosure. [Table 6]

[0149] In one embodiment, a sintered ceramic body comprises polycrystalline yttrium aluminum garnet having impurities of the trace metals Na, Fe, and Mg of 50 ppm or less as determined by ICPMS. In another embodiment, a sintered ceramic body comprises polycrystalline yttrium aluminum garnet having impurities of the trace metals Na, Fe, and Mg of 5 ppm or less as determined by ICPMS. In yet another embodiment, a sintered ceramic body comprises polycrystalline yttrium aluminum garnet having a purity of the trace elements Li, Na, Mg, K, Ca, B, P, Fe, Cu, Cr, Zn, In, Sn, and Sb (combined) of 50 ppm or less as determined by ICPMS.

[0150] Step c) of the method disclosed herein involves placing a sintered powder mixture within a volume defined by a sintering apparatus tool set to form at least one layer of the first sintered powder mixture and creating a vacuum within the volume. The spark plasma sintering (SPS) apparatus used in the process disclosed herein includes at least one graphite die, typically a cylindrical graphite die. In the graphite die, the first sintered powder mixture is placed between two graphite punches. In embodiments where a multi-layer sintered ceramic body is formed, the sintered powder mixture is added sequentially to correspond to the desired layers of sintered material.

[0151] In a preferred embodiment, the SPS tool includes a die including a sidewall with an inner wall and an outer wall, the inner wall having a diameter defining an interior volume capable of receiving at least one ceramic powder; and an upper punch and a lower punch operably coupled to the die, each having an outer wall defining a diameter smaller than the diameter of the inner wall of the die, thereby defining a gap between each of the upper 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, the gap being 10 μm to 100 μm wide. In some embodiments, the gap is 10 μm to 70 μm wide. Preferably, the die and punch are made of graphite. Such an SPS tool is disclosed in U.S. Provisional Patent Application No. 63 / 087,204, filed October 3, 2020, which is incorporated herein by reference.

[0152] In some embodiments, one or more (in the case of multi-layer embodiments) sintered powder mixtures can be placed (sequentially in the case of multi-layer embodiments) into a graphite die. Vacuum conditions known to those skilled in the art are established within the powder between punches surrounded by the die. Typical vacuum conditions include 10 -2 ~10 -3Pressures include 100 torr. A vacuum is applied primarily to remove air to protect the graphite from burning and to remove most of the air from the powder mixture. In multi-layer embodiments, the order of powder mixture placement may be reversed or repeated as needed to achieve the desired structure of the multi-layer sintered ceramic body and components formed therefrom. In such embodiments, the first and second layers of the fired powder mixture are adjacent when placed within the graphite die during sintering, and are then sintered to form first and second adjacent layers.

[0153] Step d) of the method disclosed herein includes applying pressure to at least one layer of the fired powder mixture while heating to a sintering temperature to form a sintered ceramic body including at least one layer comprising 90 volume % to 99.8 volume % polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconium, and step e) includes reducing the temperature of the sintered ceramic body, for example, by removing a heat source of a sintering apparatus to cool the sintered ceramic body.

[0154] Pressure is applied to the sintered powder mixture placed between the graphite punches and can be increased to a pressure of 5 MPa to 100 MPa, preferably 5 MPa to 60 MPa, preferably 5 MPa to 40 MPa, preferably 5 MPa to 20 MPa, preferably 5 MPa to 15 MPa, preferably 10 MPa to 60 MPa, preferably 10 MPa to 40 MPa, preferably 10 MPa to 30 MPa, preferably 10 MPa to 20 MPa, preferably 13 MPa to 18 MPa, preferably 15 MPa to 60 MPa, preferably 15 MPa to 40 MPa, preferably 15 MPa to 30 MPa, preferably 20 to 40 MPa. Pressure is applied axially to the powder mixture in the die.

[0155] In a preferred embodiment, the powder mixture is heated directly by the punch and die of the sintering apparatus. The die may be constructed of a conductive material, such as graphite, to facilitate resistive / Joule heating. Temperatures in sintering apparatus according to the present disclosure are typically measured within the graphite die of the apparatus. Therefore, it is preferred that temperatures be measured as close as possible to the sintered powder mixture being processed so that the indicated temperatures are actually realized in the sintered powder mixture.

[0156] The application of heat to the fired powder mixture and / or layered powder mixture provided in the die facilitates a sintering temperature of 1000-1700°C, preferably 1200-1700°C, preferably 1400-1700°C, preferably 1500-1700°C, more preferably 1600-1700°C, preferably 1200-1600°C, preferably 1200-1400°C, preferably 1400-1600°C, more preferably 1500-1600°C. Sintering can typically be achieved with an isothermal hold time of 0.5 to 180 minutes, preferably 0.5 to 120 minutes, preferably 0.5 to 100 minutes, preferably 0.5 to 80 minutes, preferably 0.5 to 60 minutes, preferably 0.5 to 40 minutes, preferably 0.5 to 20 minutes, preferably 0.5 to 10 minutes, preferably 0.5 to 5 minutes, preferably 5 to 120 minutes, preferably 10 to 120 minutes, preferably 20 to 120 minutes, preferably 40 to 120 minutes, preferably 60 to 120 minutes, preferably 80 to 100 minutes, preferably 100 to 120 minutes, preferably 30 to 60 minutes, or preferably 15 to 45 minutes. In certain embodiments, sintering can be achieved without an isothermal hold time, and cooling rates disclosed herein are initiated once the sintering temperature is reached. During sintering, volume reduction typically occurs, resulting in a sintered ceramic body having a volume of approximately one-third the volume of the starting powder mixture when placed in the sintering apparatus tool set. Polycrystalline YAG is preferably formed in situ by reaction sintering during the sintering process due to a combination of particle size distribution, purity and / or surface area properties of the powder mixture disclosed herein.

[0157] In one embodiment, the order of application of pressure and temperature may be varied in accordance with the present disclosure, meaning that the indicated pressure may be applied first, followed by heat to reach the desired temperature. Additionally, in other embodiments, the indicated heat may be applied first to reach the desired temperature, followed by the indicated pressure. In a third embodiment according to the present disclosure, the temperature and pressure may be applied simultaneously to the calcined powder mixture to be sintered and ramped up to reach the indicated values.

[0158] Induction or radiant heating methods can also be used to heat the sintering apparatus to indirectly heat the fired powder mixture within the tool set.

[0159] In contrast to other sintering techniques, sintering aids are not required (although they may be used if desired). Furthermore, high purity starting powders are desirable for optimal etching performance. The absence of sintering aids and the use of the high purity starting materials disclosed herein, with purities of 99.99% to about 99.9999%, enable the fabrication of high purity, high density / low porosity ceramic sintered bodies that offer improved etch resistance for use as ceramic sintered components in semiconductor etch chambers.

[0160] In one embodiment of the present invention, process step d) may further comprise a pre-sintering step with a specific heating gradient of 0.1°C / min to 100°C / min, 0.1°C / min to 50°C / min, 0.1°C / min to 25°C / min, preferably 0.5°C / min to 50°C / min, preferably 0.5 to 25°C / min, preferably 0.5 to 10°C / min, preferably 0.5°C / min to 5°C / min, preferably 0.75 to 25°C / min, preferably 1 to 10°C / min, preferably 1 to 5°C / min, until a specific pre-sintering time is reached.

[0161] In a further embodiment of the present invention, process step d) may further comprise a pre-sintering step with a specific pressure gradient of 0.50 MPa / min to 30 MPa / min, preferably 0.75 MPa / min to 20 MPa / min, more preferably 1 to 10 MPa / min, until a specific pre-sintering time is reached.

[0162] At the end of process step d), the method further comprises step e) of reducing the temperature of the sintered ceramic body by natural cooling (non-forced cooling) of the process chamber under vacuum conditions, as known to those skilled in the art. In a further embodiment of process step e), the ceramic sintered body can be cooled under convection with an inert gas, such as argon or nitrogen at 1 bar. Other gas pressures above or below 1 bar can also be used. In a further embodiment, the ceramic sintered body is cooled under forced convection in an oxygen environment. To initiate the cooling step, at the end of sintering step d, the power applied to the sintering apparatus is removed, and the pressure applied to the ceramic sintered body is removed, followed by cooling according to step e). The cooling rate of the ceramic sintered body disclosed herein can be 0.5 to 20°C / min, 1 to 10°C / min, preferably 1 to 8°C / min, preferably 1 to 5°C / min, preferably 2 to 10°C / min, preferably 2 to 8°C / min, preferably 2 to 5°C / min. At the end of process step d), the sintered ceramic body is typically very dark in colour, i.e. has an L* value <30.

[0163] Optionally, but preferably, the methods disclosed herein include annealing the sintered ceramic body (or a component formed therefrom) by applying heat to raise the temperature of the sintered ceramic body (or a component formed therefrom) to an annealing temperature and then lowering the temperature of the annealed sintered ceramic body (or a component formed therefrom). In the optional annealing step according to embodiments disclosed herein, the multilayer sintered ceramic body may be subjected to a temperature of about 900 to about 1800°C, preferably about 1250 to about 1700°C, preferably about 1300 to about 1650°C, and preferably about 1400 to about 1600°C.

[0164] In embodiments, the optional annealing of the sintered ceramic body may be carried out at a heating and / or cooling rate of 0.5°C / min to 50°C / min, preferably 0.5°C / min to 25°C / min, more preferably 0.5°C / min to 10°C / min, more preferably 0.5°C / min to 5°C / min, more preferably 1°C / min to 50°C / min, more preferably 3°C / min to 50°C / min, more preferably 5°C / min to 50°C / min, more preferably 25°C / min to 50°C / min, preferably 1°C / min to 10°C / min, preferably 2°C / min to 10°C / min, preferably 2°C / min to 5°C / min.

[0165] The duration of the optional annealing step may be from 1 to 24 hours, preferably from 1 to 18 hours, preferably from 1 to 16 hours, preferably from 1 to 8 hours, preferably from 4 to 24 hours, preferably from 8 to 24 hours, preferably from 12 to 24 hours, preferably from 4 to 12 hours, preferably from 6 to 10 hours.

[0166] In some embodiments, optional annealing according to the present disclosure can be performed in a sintering apparatus after the sintering process. The optional annealing process can be preferably performed under oxidizing conditions, such as forced convection, or in air. Annealing improves the chemical and physical properties of the sintered ceramic body or a component made therefrom through the reduction of oxygen vacancies for stoichiometric correction and the reduction of stress in the sintered body or component. The optional process step of annealing the sintered corrosion-resistant component is performed in an oxidizing atmosphere, whereby the annealing process can provide an increase in albedo, improved mechanical handleability, and reduced porosity. After the optional process step of annealing the multilayer sintered ceramic body is performed, the temperature of the sintered, and optionally annealed, multilayer sintered ceramic body is reduced to ambient temperature by removing the heat source. At the end of process step e), the annealed sintered ceramic body is typically lighter in color due to oxidation, i.e., has an L* value of 70 to 85. A 22-inch round part (2,452 cm) made according to the methods disclosed herein was measured. 2An example of color measurements made on an annealed YAG layer of 1000 nm is shown in Table 7. Five measurements were made across the part, and the mean and standard deviation for each color variable are shown in Table 7. [Table 7]

[0167] Step f) of the method disclosed herein is exposing the sintered ceramic body to UV radiation for a time period of 1 to 400 minutes. The purpose of the UV exposure step is to activate the doped zirconium and impart a red color to the sintered ceramic body. The length of time for UV radiation exposure should be determined by the uniformity and intensity of the red color imparted to the sintered ceramic body. The total exposure time will depend on the intensity of the UV lamp used to irradiate the sintered ceramic body.

[0168] In a preferred embodiment, the UV radiation is applied at a distance of 3 inches from the sintered ceramic body for an exposure time of about 6 hours, e.g., H + It is delivered by a UV lamp such as the Heraeus Noblelight Hammer Mark II LH10 Lamp System, which uses a bulb and R500 reflector.

[0169] At the end of process step f), the sintered ceramic body comprises at least one layer comprising 90 vol.% to 99.8 vol.% polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconium, the at least one layer comprising at least one surface, and the at least one surface contains pores, and the pores Pore ​​diameter not exceeding 5 μm death , having a maximum pore diameter of 1.5 μm for at least 95% of the pores death At least one surface exhibits an L* value of 50 to 77, preferably 50 to 60, an a* value of 6 to 12 and a b* value of 3 to 6, and at least one layer has a thickness of 500 μm to 2 cm, and the L* and a* values Coefficient of variation is less than 10% over at least one surface be .

[0170] The above-described process is suitable for producing sintered ceramic bodies as disclosed herein, for example, having a maximum dimension of 100 to about 625 mm, preferably 100 to 622 mm, preferably 200 to about 625 mm, preferably 300 to about 625 mm, preferably 400 to about 625 mm, preferably 500 to about 625 mm, preferably 300 to 622 mm, preferably 400 to 622 mm, preferably 500 to 622 mm. Despite their large size, sintered ceramic bodies produced according to the methods disclosed herein have a uniform density of approximately 99.5% of the theoretical value for YAG. The sintered ceramic bodies are formed, for example, into disk shapes whose maximum dimension is the diameter. The disclosed process provides rapid powder consolidation and densification, maintains a maximum grain size of about 10 μm or less in the sintered ceramic body, and achieves high density and low porosity within at least one first layer across the maximum dimension. This combination of fine grain size, high density and CTE matching provides high strength sintered ceramic bodies of large size suitable for machining, handling and use as components in semiconductor plasma processing chambers.

[0171] Step j) of the methods disclosed herein involves machining the sintered ceramic body (or the annealed sintered ceramic body) to produce sintered ceramic components in the shape of windows, lids, 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. Machining, drilling, boring, grinding, lapping, polishing, and the like, as known to those skilled in the art, can be performed as needed to form the sintered ceramic body into the desired shape of a component for use in a plasma processing chamber. The use of powder mixtures in the composition ranges disclosed herein can provide sintered ceramic bodies with improved machinability due to the use of CTE-matched layers, thereby reducing stress during the machining step of the disclosed methods.

[0172] The methods and compositions disclosed herein are further illustrated by reference to the following examples, but it should be understood that they are not to be construed as limiting. [Example]

[0173] In order to more clearly demonstrate the overall nature of the present disclosure, the following examples are included, which are intended to illustrate, but not limit, the disclosure.

[0174] Measurements for all examples were performed using the disclosed equipment and methods. Purity measurements were performed using an Agilent 7900 ICP-MS model G8403. The specific surface area (SSA) of powders and powder mixtures was measured using a Horiba BET Surface Area Analyzer model SA-9601. Specific surface area measurements were performed according to ASTM C1274. Particle size was measured using a Horiba model LA-960 Laser Scattering Particle Size Distribution Analyzer, which can measure particle sizes from 10 nm to 5 mm. In all examples, given the need to minimize contamination, the total concentration of undesirable elements in the raw materials used was a maximum of 1 atomic %.

[0175] The sintered ceramic bodies produced in the following examples were circular and had a diameter of 620 mm.

[0176] Example 1 YAG - no dopant 4.5~6m 2 yttria powder (purity 99.9984%, impurities of approximately 16 ppm by mass) having a specific surface area of ​​6 to 8 m / g, a d10 particle size of 2.0 to 3.5 μm, a d50 particle size of 4.0 to 6.5 μm, and a d90 particle size of 6.5 to 10 μm; 2Alumina powder (purity approximately 99.9995%, with approximately 5 ppm impurities by mass) having a specific surface area of ​​0.075-0.2 μm / g, a d10 particle size of 0.075-0.2 μm, a d50 particle size of 2.5-5.5 μm, and a d90 particle size of 15-22 μm was combined in a molar ratio to form a powder mixture that reacts upon sintering to form a ceramic sintered body containing a cubic yttrium aluminum garnet (YAG) phase. High-purity alumina media (greater than 99.9% as measured by ICPMS) was added at a loading of approximately 60% by powder weight, and ethanol was added in an amount of approximately 35% by combined ethanol and powder weight to form a slurry. Tumble mixing or end-over-end mixing, as known to those skilled in the art, was performed for 20 hours, after which the ethanol was extracted from the powder mixture using rotary evaporation according to known methods. When calcined in air at 1050°C for 6 hours, the calcined powder mixture had a solubility of 4-6 m. 2 The powder, powder mixture, and / or calcined powder mixture may be sieved, for example, using openings of 45-400 μm, and calcined, blended, and / or milled in various process steps according to methods known to those skilled in the art. Purity was measured using the ICPMS method disclosed herein, and a total impurity content of the calcined powder mixture was measured to be about 5 ppm based on the total mass of oxides calculated from all constituents, corresponding to a purity of about 99.9995%. The purity limits and impurity contents of the yttria and alumina starting powders and the calcined powder mixture disclosed herein do not include Si. The detection limit for Si using the ICPMS method of measuring purity disclosed herein is about 14 ppm, and therefore, the yttria and alumina starting powders and the calcined powder mixture may contain Si in the form of silica at a detection level of about 14 ppm. The calcined powder mixture was placed within a volume defined by the toolset of a sintering apparatus disclosed herein and subjected to 10 -2 ~10 -3A vacuum of 1000 torr was created within the volume. A pressure of 5 MPa was applied, and the sintered powder mixture within the volume was heated from ambient temperature to 800 °C at approximately 10 °C / min. The pressure was then increased at a rate of approximately 0.4 to approximately 0.6 MPa / min, and the temperature gradient continued as before, until sintering conditions of 1600 °C and 15 MPa were reached over 60 minutes, forming polycrystalline YAG sintered ceramic bodies in the shape of a disk with a maximum dimension of 150 mm. Density measurements were performed on the as-sintered and annealed samples according to ASTM B962-17. A density of 4.549 g / cc was obtained, averaged over five measurements. This corresponds to 99.854% of the theoretical density of YAG (reported herein as 4.556 g / cc) and a corresponding volumetric porosity of 0.146%, respectively, calculated from the density measurements. The processed samples have a slightly transparent dark gray ceramic appearance when thinly ground for optical transmission. The sample is then oxidized at 1400 °C for 8 h using a heating rate of 1-5 °C / min up to 1400 °C, resulting in a translucent white material.

[0177] Example 2 Zr doping 4.5~6m 2 yttria powder (purity 99.9984%, impurities of approximately 16 ppm by mass) having a specific surface area of ​​6 to 8 m / g, a d10 particle size of 2.0 to 3.5 μm, a d50 particle size of 4.0 to 6.5 μm, and a d90 particle size of 6.5 to 10 μm; 2 Alumina powder (purity approximately 99.9995%, impurities approximately 5 ppm by mass) having a specific surface area of ​​0.075-0.2 μm / g, a d10 particle size of 0.075-0.2 μm, a d50 particle size of 2.5-5.5 μm, and a d90 particle size of 15-22 μm was combined in a molar ratio to form a powder mixture that reacts upon sintering to form a ceramic sintered body containing a cubic yttrium aluminum garnet (YAG) phase. High-purity alumina media (greater than 99.9% as measured by ICPMS) was added at a loading of approximately 60% by powder weight, and ethanol was added in an amount of approximately 35% by combined weight of the ethanol and powder to form a slurry. Furthermore, a 6.0-8.0 μm 2Yttria-stabilized zirconia powder with a specific surface area of ​​0.075-0.2 μm / g, a d10 particle size of 0.25 μm-0.45 μm, and a d90 particle size of 1.0-2.0 μm was added to the mixture at the appropriate dopant level (purity of approximately 99.9954%, impurities of approximately 46 ppm by mass, excluding typical yttrium and hafnium impurities as are typical for stabilized zirconia). Tumble mixing or end-over-end mixing, as known to those skilled in the art, was performed for 20 hours, after which the ethanol was extracted from the powder mixture using rotary evaporation according to known methods. When calcined in air at 1050°C for 6 hours, the calcined powder mixture had a viscosity of 4-6 m / s. 2 The powder, powder mixture, and / or calcined powder mixture may be sieved, for example, using openings between 45 and 400 μm, and calcined, blended, and / or milled in various process steps according to methods known to those skilled in the art. Purity was measured using the ICPMS method disclosed herein, and a total impurity content of the calcined powder mixture was measured to be approximately 5 ppm based on the total mass of oxides calculated from all constituents, corresponding to a purity of approximately 99.9995%. The purity limits and impurity content of the yttria and alumina starting powders and the calcined powder mixture disclosed herein do not include Si. The detection limit for Si using the ICPMS method of measuring purity disclosed herein is approximately 14 ppm, and therefore, the yttria and alumina starting powders and the calcined powder mixture may contain Si in the form of silica at a detection level of approximately 14 ppm. The calcined powder mixture was placed within a volume defined by the toolset of the SPS sintering apparatus disclosed herein and sintered for 10 minutes. -2 ~10 -3A vacuum of 1000 torr was created within the volume. A pressure of 5 MPa was applied, and the sintered powder mixture within the volume was heated from ambient temperature to 800 °C at approximately 10 °C / min. The pressure was then increased at a rate of approximately 0.4 to approximately 0.6 MPa / min, and the temperature gradient continued as before, over 60 minutes, until sintering conditions of 1600 °C and 15 MPa were reached, forming polycrystalline YAG sintered ceramic bodies in the shape of disks with a maximum dimension of 150 mm. Density measurements were performed on the as-sintered and annealed samples according to ASTM B962-17. A density of 4.549 g / cc was obtained, averaged over five measurements. This corresponds to 99.854% of the theoretical density of YAG (reported herein as 4.556 g / cc) and a corresponding volumetric porosity of 0.146%, respectively, calculated from the density measurements. The processed samples have a slightly transparent dark red / black ceramic appearance when thinly ground for optical transmission. The sample is then oxidized at 1400 °C for 8 h using a heating rate of 1-5 °C / min up to 1400 °C, resulting in a translucent white material.

[0178] For the samples with and without doped zirconium, the UV irradiation step was performed using a UV lamp (H + The measurements were performed using a Heraeus Noblelight Hammer Mark II LH10 Lamp System using a bulb and an R500 reflector. The results are shown in Table 8. Sample 144 was prepared according to Example 1 above, while Samples 135, 149, and 142 were prepared according to Example 2, but with varying amounts of doped zirconium. Sample 144 (0 ppm Zr) had a slight color change response, exhibiting a slight pink color compared to the strong red coloration of Sample 135. [Table 8]

[0179] Example 3: Porosity Measurement Two sintered ceramic bodies (designated 210 and 219) were prepared according to the method of Example 2 (doped with 50 ppm zirconium). The surfaces were polished, and the level of porosity was measured across the sample surface using SEM images (FIGS. 2A and 2B) obtained from a Phenom XL scanning electron microscope at 10,000x magnification. The images were imported into ImageJ software for analysis. ImageJ, developed at the National Institutes of Health (NIH), is a Java-based, public-domain image processing and analysis program for image processing of scientific multidimensional images.

[0180] Pore ​​sizes were measured across seven SEM images using the ImageJ software method disclosed herein. Sample 210 showed a maximum pore size of 1.01 μm, and sample 219 showed a maximum pore size of 0.94 μm.

[0181] A number of embodiments have been described as disclosed herein. However, it will be understood that various modifications can be made without departing from the spirit and scope of the embodiments disclosed herein. Accordingly, other embodiments are within the scope of the following claims.

Claims

1. 1. A sintered ceramic body comprising at least one layer comprising 90 volume % to 99.8 volume % polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconium, wherein the at least one layer comprises at least one surface, the at least one surface comprising pores, the pores having a pore size not exceeding 5 μm, the at least one surface exhibiting an L* value of 50 to 77 and an a* value of 6 to 12, the at least one layer having a thickness of 500 μm to 2 cm, and a coefficient of variation of the L* and a* values ​​being 10% or less across the at least one surface.

2. 10. The sintered ceramic body of claim 1, wherein the at least one layer has a b* value of 3-6.

3. 3. The sintered ceramic body of claim 2, wherein the coefficient of variation of b* is 15% or less across the at least one surface.

4. 4. The sintered ceramic body according to claim 1, wherein the coefficient of variation of L* is 3% or less and the coefficient of variation of a* is 9% or less across the at least one surface.

5. 4. The sintered ceramic body according to claim 1, wherein the polycrystalline yttrium aluminum garnet contains pores having a pore diameter of not more than 1.75 μm for at least 97% of all pores, and the polycrystalline yttrium aluminum garnet has a volume porosity of 0.1 to 3%.

6. The polycrystalline yttrium aluminum garnet may be ２ O ３ 4. The sintered ceramic body of claim 1, wherein the sintered ceramic body is present in an amount of 93 to 99.8 volume %, excluding zirconium.

7. 4. The sintered ceramic body of any one of claims 1 to 3, wherein the polycrystalline ceramic body has trace metal Na, Fe, and Mg impurities of 50 ppm or less as determined by ICPMS.

8. The sintered ceramic body of any one of claims 1 to 3, wherein the pores occupy less than 0.2% of the surface area.

9. 4. The sintered ceramic body of claim 1, having a maximum dimension of 100 mm to 625 mm.

10. 10. The sintered ceramic body of claim 9, having a density variance measured across said largest dimension of 0.2 to less than 5%.

11. 1. A method for preparing a sintered ceramic body, comprising: a. combining an yttria powder, an alumina powder, and a zirconium-containing powder providing 15-500 ppm zirconium to form a first powder mixture; b. firing the first powder mixture by applying heat to raise the temperature of the first powder mixture to a firing temperature and maintaining the firing temperature to form a first fired powder mixture; c) placing the first fired powder mixture within a volume defined by a sintering machine toolset to form at least one layer of the first fired powder mixture and creating a vacuum condition within the volume; d. applying pressure to the at least one layer of the first fired powder mixture while heating to a sintering temperature and sintering to form a sintered ceramic body comprising the at least one layer comprising 90% to 99.8% by volume polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconium; e. reducing the temperature of the sintered ceramic body; f. exposing the sintered ceramic body to UV radiation for a time period of 1 to 400 minutes; Including, the first calcined powder mixture having a total impurity content of 150 ppm or less; The yttria powder and the alumina powder in step a) each have a thickness of about 18 mm as measured in accordance with ASTM C1274. ２ / g or less specific surface area, the sintered ceramic layer comprises at least one layer comprising 90% to 99.8% by volume polycrystalline yttrium aluminum garnet (YAG) and 15 ppm to 500 ppm zirconium; the at least one layer comprising at least one surface; the at least one surface comprises pores; the pores have a pore size not exceeding 5 μm; having a maximum pore size of 1.5 μm for at least 95% of the pores; said at least one surface exhibiting an L* value of 50 to 77 and an a* value of 6 to 12; said at least one layer having a thickness of 500 μm to 2 cm; the coefficient of variation of L* and a* is 10% or less across the at least one surface; A method for preparing a sintered ceramic body.

12. The following steps: g. annealing the sintered ceramic body by applying heat to raise the temperature of the sintered ceramic body to an annealing temperature and annealing; h. reducing the temperature of the annealed multi-layer sintered ceramic body; i. optionally machining the sintered ceramic body or the annealed sintered ceramic body to produce a sintered ceramic component in the shape of a dielectric window, an RF window, a focus ring, a process ring, a deposition ring, a nozzle or gas injector, a showerhead, a gas distribution plate, an etch chamber liner, a plasma source adapter, a gas inlet adapter, a diffuser, an electrostatic wafer chuck (ESC), a chuck, a puck, an ion suppressor element, a faceplate, an isolator, a spacer, and / or a guard ring in a plasma processing chamber; The method of claim 11 further comprising:

13. 13. The method of claim 11 or 12, wherein the toolset comprises a graphite die having a volume, an inner wall, and first and second openings, and first and second punches operatively coupled to the die, each of the first and second punches having an outer wall defining a diameter smaller than a diameter of the inner wall of the die, thereby forming a gap between each of the first and second punches and the inner wall of the die when at least one of the first and second punches moves within the volume of the die.

14. 14. The method of claim 13, wherein the gap is a distance of 10 to 100 μm between the inner wall of the die and the outer wall of each of the first and second punches.

15. The method according to claim 11 or 12, wherein the sintering temperature is 1000 to 1500°C.

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