Anodizing of metal matrix composite semiconductor processing chamber components.

Abstract

A semiconductor processing chamber component formed of a metal-based composition has an anodized layer on its surface. The anodized layer includes an aluminum oxide layer formed on an AlSiC composition. The anodized layer provides the component with protection against corrosion by plasma processing gases while providing a protective coating. An aluminum layer is plated onto the surface of the component, and then the aluminum layer is anodized to form the protective layer.

Description

[Technical Field]

[0001] REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 070,722, filed August 26, 2020, which is incorporated herein by reference for all purposes.

[0002] The present disclosure relates generally to the manufacture of semiconductor devices. In particular, the present disclosure relates to chamber components used in the manufacture of semiconductor devices. [Background technology]

[0003] During semiconductor wafer processing, plasma processing chambers are used to process semiconductor devices. Plasma processing chambers are exposed to plasma, which can degrade components within the plasma processing chamber. For example, electrostatic chuck (ESC) base plates are an essential component of etch chambers as part of the subsystem on which the wafer rests. Because ESCs can be exposed to corrosive plasma and high electrostatic potentials, metal matrix composites can be used as base plate substrates to enhance the reliability of plasma-sprayed coated substrates operating over a wide temperature range.

[0004] Anodizing is used as an inexpensive method to protect components such as base plate substrates from the extreme conditions of processing chambers, including plasma erosion and mechanical adhesive wear. However, standard anodizing techniques have proven unsuccessful on metal composite structures due to the leaky and porous nature of metal composites. The confinement of metal within the metal composite prevents the growth of a uniform anodic oxide film, resulting in a non-planar, unreliable anodic native oxide film with poor corrosion protection in plasma environments. The presence of reinforcing particles on the surface of metal composite structures also prevents the formation of a continuous, unbroken barrier oxide layer, reducing the effectiveness of the anodization process. Therefore, it is desirable to be able to form a protective coating, such as a uniform anodic oxide layer, on metal matrix composite components in order to create semiconductor processing chamber components that are more resistant to corrosive plasma materials.

[0005] The Background Art set forth herein is intended to present the contents of the present disclosure generally, and the inventions of the presently named inventors are not admitted expressly or impliedly as prior art to the present disclosure to the extent that they are described in this Background Art section and in a descriptive manner that does not constitute prior art at the time of filing. Summary of the Invention

[0006] According to an embodiment, a component for a semiconductor processing chamber is provided, the component including a body including a metal matrix composite and an anodized layer on the body.

[0007] According to another embodiment, a method is provided for forming an anodization layer on a body comprising a metal matrix composite. A body is provided comprising a metal matrix composite. An aluminum layer is plated on a surface of the body, the aluminum being at least 99% pure by weight. The aluminum layer is anodized to form the anodization layer.

[0008] According to yet another embodiment, an anodized layer is provided for a body comprising a metal matrix composite in a semiconductor processing chamber. A body comprising a metal matrix composite is provided. An aluminum layer is plated on a surface of the body, the aluminum being at least 99% pure aluminum by weight. The aluminum layer is anodized to form the anodized layer. [Brief explanation of the drawings]

[0009] The present disclosure is illustrated by way of example, and not limitation, in the figures of the accompanying drawings, in which like reference numerals represent like elements and in which:

[0010] [Figure 1] 1 is a high-level flowchart of an embodiment for providing an ESC system.

[0011] [Figure 2A] FIG. 10 is a bottom view of a plate used in an ESC system according to an embodiment.

[0012] [Figure 2B] Top view of the plate shown in Figure 2A.

[0013] [Figure 2C] FIG. 2C is a cross-sectional side view of the plate shown in FIGS. 2A and 2B.

[0014] [Figure 3A] 10 is a cross-sectional view of a portion of a plate after anodization according to an embodiment.

[0015] [Figure 3B] FIG. 10 is a cross-sectional view of a portion of a plate after anodization according to another embodiment.

[0016] [Figure 3C] FIG. 10 is an enlarged cross-sectional view of a gas path after anodization according to an embodiment.

[0017] [Figure 3D] FIG. 10 is an enlarged cross-sectional view of a gas path after anodization according to another embodiment.

[0018] [Figure 4] 1 is a schematic diagram of a plasma processing system for plasma processing a substrate. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present disclosure will now be described in detail with reference to several preferred embodiments thereof, as illustrated in the accompanying drawings. In the following description, several specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure may be practiced without some or all of these specific details. In other instances, well-known process steps and / or structures have not been described in detail in order to avoid unnecessarily obscuring the present disclosure.

[0020] Metal matrix composites are desirable component materials for plasma processing chamber components. Metal matrix composites may be used for plasma chamber components such as ESC base plates. However, the metal parts of the ESC may be exposed to higher voltages than the chamber body. It is necessary to protect the metal parts of the ESC from chemical degradation and electrical discharges. Etch-resistant coatings can provide additional protection for such plasma chamber components. Metal matrix composites are composite materials formed by dispersing a reinforcing material (metal or non-metal, such as a ceramic or organic compound) in a matrix of a continuous solid-phase monolithic metal material.

[0021] Current protective coatings for ESC base plates include anodized layers, ceramic thermal spray coatings, or thermal spray coatings on anodized layers. Some products use aluminum nitride coatings grown directly on the surface of the aluminum base plate. When anodized on aluminum on flat surfaces, it collapses at approximately 2 kilovolts (kV) for a 0.002-inch (0.00508 cm) thick coating and 600 volts (V) at corner radii. Thermal spray coatings, when applied perpendicular to the surface, can withstand up to 10 kV on flat surfaces but only about 4–5 kV at corner radii. Thermal spray coatings can be sealed with polymers, but all known effective sealing methods fail, especially when exposed to fluorine-containing plasmas under chamber operating conditions. Attempts to further improve collapse by increasing coating thickness have led to existing technology reaching its limits at these values, as the mismatch between the coefficient of thermal expansion (CTE) of the substrate and the CTE of the coating material causes cracking in response to thermal cycling.

[0022] Various embodiments described herein provide ESCs that are resistant to damage from arcing and / or corrosion due to plasma etching. For ease of understanding, FIG. 1 is a high-level flowchart of an embodiment for providing an ESC system. A plate is formed (step 104). FIG. 2A is a bottom view of plate 204 used in ESC system 200 provided in an embodiment. The bottom view of plate 204 shows a first side of plate 204. In this embodiment, the first side of plate 204 is a flat surface.

[0023] In this embodiment, the plate 204 is formed of a metal matrix composite. In some embodiments, the metal matrix composite is aluminum-silicon carbide (AlSiC), which comprises an aluminum matrix with dispersed silicon carbide (SiC) particles, fibers, or whiskers. AlSiC comprises silicon carbide dispersed in a continuous, solid, monolithic aluminum matrix. In some embodiments, the plate 204 formed of AlSiC comprises 30-75% silicon carbide by volume. In other embodiments, the plate 204 formed of AlSiC comprises 40-60% silicon carbide by volume. An ESC system 200 built using a plate 204 formed of AlSiC offers significant advantages over conventional base plate technologies. AlSiC offers a combination of low CTE and high thermal conductivity.

[0024] The plate 204 includes multiple internal gas passages 206 and 208. Each of the gas passages 206 and 208 has an outlet on the bottom surface 204A or backside of the plate 204. As shown in FIG. 2A, the gas passage holes 206 and through-holes 208 are shown in a bottom view of the plate 204. FIG. 2B is a top view of the plate 204 showing the coolant passages 210 on the top surface 204B of the plate 204. Wafer backside cooling gas can flow through the cooling gas distribution passages 210 in a direction substantially parallel to the surface of a first side of the plate 204. In some embodiments, the wafer backside cooling gas is helium.

[0025] 2C is a side view of the plate 204 of the ESC system 200. As shown in FIG. 2C, the gas through-holes 208 extend all the way through to the top surface 204B of the plate 204. Each gas flow hole 206 extends to and terminates in a cooling gas distribution channel 210.

[0026] After the plate 204 is formed and provided (step 104), an aluminum layer 212 is formed on the bottom surface 204A of the plate 204 (step 108), as shown in Figure 2C. The aluminum layer 212 is plated on the bottom surface 204A of the plate 204 and the inner surfaces of the gas passages 206 and 208.

[0027] In some embodiments, the aluminum layer 212 is plated to form a cladding layer on the metal matrix composite plate 204. In some embodiments, the aluminum layer 212 is deposited using a deposition method such as atomic layer deposition (ALD) or plasma electrolytic oxidation (PEO). This aluminum layer 212 aids in the formation of an anodized overlayer 214 (described below) that is more uniform, has minimal porosity, and has low trace contaminants compared to standard anodization. This anodized layer 214 is a corrosion-resistant barrier against aggressive plasma environments and also provides voltage standoff protection from high-voltage plasma environments. In some embodiments, the aluminum layer 212 is at least 99% pure aluminum by weight. In other embodiments, the aluminum layer 212 is at least 99.5% pure aluminum by weight. In yet other embodiments, the aluminum layer 212 is at least 99.9% pure aluminum by weight.

[0028] After aluminum layer 212 is formed, ESC system 200 (including plate 204) is anodized (step 112) to form anodized layer 214. FIG. 3A is a cross-sectional view of an embodiment of a portion of plate 204 after anodization, showing anodized layer 214. As shown in FIG. 3A, in some embodiments, anodized layer 214 is at least 10 microns thick and can be as thick as 50 microns. In other embodiments, anodized layer 214 has a thickness of 25-50 microns. In some embodiments, aluminum layer 212 after anodization is less than 10 microns thick. The thickness of aluminum layer 212 in some embodiments is at least one-third the thickness of anodized layer 214 after anodization.

[0029] In other embodiments, the anodization process anodizes all of the aluminum layer 212, so that there is no aluminum layer between the anodized layer 214 and the plate 204 after anodization, as shown in Figure 3B. The bottom surface of the plate 204, in accordance with embodiments, has at least one opening to the gas paths 206 and 208, and the anodized layer 214 is also formed on the interior surfaces of the gas paths 206 and 208. In some embodiments having more than one gas path 206 and 208, the anodized layer 214 is also formed on the interior surface of each of the gas paths 206 and 208.

[0030] In one embodiment, the anodized layer 214 is an aluminum oxide layer having an aluminum oxide purity of at least 99% by weight. In another embodiment, the anodized layer 214 is an aluminum oxide layer having an aluminum oxide purity of at least 99.5% by weight. In yet another embodiment, the anodized layer 214 is an aluminum oxide layer having an aluminum oxide purity of at least 99.9% by weight. The anodized layer 214 has a porosity of 0.5% by volume or less. In some embodiments, the porosity of the anodized layer 214 is between 0.1 and 0.5% by volume.

[0031] The ESC system 200 is then installed in a plasma processing chamber (step 116). In an embodiment, a ceramic plate is mounted on the plate 204. A gas source is placed in fluid communication with the gas openings 208. In this embodiment, the gas source provides helium. The helium is provided to transfer heat between the ceramic plate and the plate 204. A coolant source is placed in fluid communication with the coolant channels 224. The coolant source provides coolant to control the temperature of the ESC system 200. The ESC system 200 supports a substrate to be processed. The ESC system 200 is used in plasma processing of the substrate (step 120). The ESC system 200 supports the substrate during processing and is exposed to plasma and high potentials during processing.

[0032] Forming aluminum layer 212 on plate 204 provides a layer 212 that can be anodized to form a corrosion-resistant aluminum oxide layer 214. The aluminum oxide layer 214 formed by anodization provides an improved protective layer, including over more complex geometries such as the interior of gas paths 206 and 208. The improved protective aluminum oxide layer 214 is more resistant to arcing and other damage (such as corrosion from plasma etching).

[0033] The plated aluminum layer 212 allows for coating of surfaces such as the interior surfaces of the gas paths 206 and 208 that are difficult to coat because anodization of the aluminum layer 212 forms a protective aluminum oxide layer 214. Figure 3C is an enlarged cross-sectional view of an embodiment of the gas paths 206 and 208 having a protective aluminum oxide layer 214 on the substantially pure aluminum layer 212 on the interior surfaces of the gas paths 206 and 208. Figure 3D is an enlarged cross-sectional view of another embodiment of the gas paths 206 and 208 having a protective aluminum oxide layer 214 on the interior surfaces of the gas paths 206 and 208. In the embodiment shown in Figure 3D, there is no aluminum layer between the aluminum oxide layer 214 and the gas paths 206 and 208 because the anodization process anodized all of the aluminum layer.

[0034] Unlike metal alloys, substantially pure aluminum (at least 99% pure aluminum by weight) being anodized reduces inherent contamination risks. The anodization quality of the subsequent aluminum oxide layer 214 is greatly improved by eliminating defects and voids in the surface oxide layer. High-purity aluminum material also offers the added benefit of greatly reducing plasma etch chamber contamination from the substrate or at the anodized layer. This superior structure results in improved corrosion, dielectric, and wear performance compared to stand-alone standard anodization processes on metal matrix composites.

[0035] FIG. 4 is a schematic diagram of a plasma processing system 400 for plasma processing a substrate, in which components may be mounted in embodiments. In one or more embodiments, the plasma processing system 400 includes a plasma processing chamber 404 surrounded by a chamber wall 450 and a gas distribution plate 406 providing gas inlets and an ESC system 200. Within the plasma processing chamber 404, a substrate 407 is placed on the ESC system 200. An ESC power supply 448 may provide bias power to the ESC system 200. A gas source 410 is connected to the plasma processing chamber 404 through the gas distribution plate 406. A cooling system 451 is fluidly connected to the cooling gas distribution channels 210 of the ESC system 200 and provides temperature control of the ESC system 200. A backside gas system 452 is fluidly connected to the gas paths 206 and 208. In this embodiment, the backside gas system 452 provides a helium flow. A radio frequency (RF) power supply 430 provides RF power to the ESC system 200 and the upper electrode. In this embodiment, the upper electrode is a gas distribution plate 406. In a preferred embodiment, 13.56 megahertz (MHz), 2 MHz, 60 MHz, and / or 27 MHz power sources, if desired, comprise the RF power source 430 and the ESC power source 448. A controller 435 is controllably connected to the RF power source 430, the ESC power source 448, the exhaust pump 420, and the gas source 410. A high-flow liner 460 is a liner within the plasma processing chamber 404. The high-flow liner 460 confines gas from the gas source and has slots 462. The slots 462 maintain a controlled flow of gas from the gas source 410 through the exhaust pump 420. An example of such a plasma processing chamber is the Exelan Flex® Etch System manufactured by Lam Research Corporation of Fremont, California. The processing chamber can be a CCP (capacitively coupled plasma) reactor or an ICP (inductively coupled plasma) reactor.

[0036] The plasma processing chamber 404 is used to plasma process the substrate 407. The plasma processing may be one or more of etching, deposition, passivation, or another plasma process. The plasma processing may be performed in conjunction with a non-plasma process. Such a process may expose the ESC system 200 to a plasma containing halogen and / or oxygen.

[0037] While this disclosure has been described in terms of several preferred embodiments, there are alterations, substitutions, modifications, and various substitute equivalents that fall within the scope of this disclosure. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of this disclosure. It is therefore intended that the following appended claims be interpreted to include all such alterations, substitutions, and various substitute equivalents that fall within the true spirit and scope of this disclosure. The present disclosure may be realized in the following forms. [Form 1] 1. A component of a semiconductor processing chamber, comprising: a body including a metal matrix composite; an anodized layer on the body; Component parts, including: [Form 2] The component according to aspect 1, The component, wherein the metal matrix composite comprises AlSiC. [Form 3] The component according to aspect 1, further comprising: The component includes an aluminum layer between the body and the anodized layer. [Form 4] The component according to aspect 3, The component, wherein the aluminum layer is at least 99% by mass pure aluminum. [Form 5] The component according to aspect 3, The component, wherein the aluminum layer is at least 99.5% by mass pure aluminum. [Form 6] The component according to aspect 3, The component, wherein the aluminum layer is at least 99.9% by weight pure aluminum. [Form 7] The component according to aspect 2, The AlSiC component contains 30 to 75 volume % silicon carbide. [Form 8] The component according to aspect 1, The anodized layer is formed on a bottom surface of the body. [Form 9] The component according to aspect 1, The component, wherein the anodized layer is an aluminum oxide layer having an aluminum oxide purity of at least 99% by weight. [Form 10] The component according to aspect 1, The component, wherein the anodized layer has a porosity of 0.1 to 0.5% by volume. [Form 11] The component according to aspect 1, The anodized layer has a thickness of 10 to 50 microns. [Form 12] 11. The component according to claim 10, The component, wherein the anodized layer has a thickness of less than 50 microns. [Form 13] 11. The component according to claim 10, The component, wherein the anodized layer has a thickness of less than 10 microns. [Form 14] The component according to aspect 1, The component is a base plate, and further comprises a plurality of internal gas passages, each internal gas passage having a surface including an anodized layer and having an outlet on an underside of the base plate. [Form 15] 1. A method for forming an anodized layer on a body comprising a metal matrix composite, comprising: providing the body comprising the metal matrix composite; plating an aluminum layer on the surface of the body, the aluminum being at least 99% pure by weight; anodizing the aluminum layer to form an anodized layer; A method comprising: [Form 16] 16. The method of claim 15, The method, wherein the metal matrix composite comprises AlSiC. [Form 17] 16. The method of claim 15, The method, wherein the aluminum in the aluminum layer is at least 99.5% by weight pure aluminum. [Form 18] 16. The method of claim 15, The method, wherein the aluminum in the aluminum layer is at least 99.9% by weight pure aluminum. [Form 19] 16. The method of claim 15, The method wherein the thickness of the aluminum layer is at least one-third the thickness of the anodized layer after anodization. [Form 20] 16. The method of claim 15, The method, wherein the surface of the body includes at least one opening to an internal flow passage, and the anodized layer is formed on a surface inside the internal flow passage. [Form 21] 1. A component of a semiconductor processing chamber, comprising: 16. A component formed by the method of claim 15. [Form 22] 22. The component according to claim 21, The component is a base plate, and further comprises a plurality of internal gas passages, each internal gas passage having a surface including an anodized layer and having an outlet on an underside of the base plate.

Claims

1. 1. A component of a semiconductor processing chamber, comprising: a body including a metal matrix composite formed by dispersing a reinforcement material in a matrix of a continuous solid phase monolithic metallic material; an anodized layer on the body; an aluminum layer between the body and the anodized layer; Including, The component, wherein the aluminum layer is at least 99% by weight pure aluminum.

2. 10. The component of claim 1, The component, wherein the metal matrix composite comprises AlSiC.

3. 10. The component of claim 1, The component, wherein the aluminum layer is at least 99.5% by weight pure aluminum.

4. 10. The component of claim 1, The component, wherein the aluminum layer is at least 99.9% by weight pure aluminum.

5. Component according to claim 2, The component, wherein the AlSiC comprises 30 to 75 volume percent silicon carbide.

6. 10. The component of claim 1, the anodized layer is formed on a bottom surface of the body; the body is a plate used in an electrostatic chuck (ESC) system; The bottom surface is a surface opposite to a surface on which a semiconductor wafer is placed.

7. 10. The component of claim 1, The component, wherein the anodized layer is an aluminum oxide layer having an aluminum oxide purity of at least 99% by weight.

8. 10. The component of claim 1, The component, wherein the anodized layer has a porosity of 0.1 to 0.5 volume percent.

9. 10. The component of claim 1, The component wherein the anodized layer has a thickness of 10 to 50 microns.

10. 9. The component of claim 8, The component wherein the anodized layer has a thickness of less than 50 microns.

11. 9. The component of claim 8, The component wherein the anodized layer has a thickness of less than 10 microns.

12. 10. The component of claim 1, The component is a base plate, and further comprises a plurality of internal gas passages, each internal gas passage having a surface including an anodized layer and having an outlet on an underside of the base plate.

13. 1. A method for forming an anodized layer on a body comprising a metal matrix composite, comprising: providing the body comprising a metal matrix composite formed of a matrix of continuous solid phase monolithic metallic material having a reinforcing material dispersed therein; plating an aluminum layer on the surface of the body, the aluminum being at least 99% pure by weight; anodizing the aluminum layer to form an anodized layer; A method comprising:

14. 14. The method of claim 13, The method, wherein the metal matrix composite comprises AlSiC.

15. 14. The method of claim 13, The method, wherein the aluminum in the aluminum layer is at least 99.5% by weight pure aluminum.

16. 14. The method of claim 13, The method, wherein the aluminum in the aluminum layer is at least 99.9% by weight pure aluminum.

17. 14. The method of claim 13, The method wherein the thickness of the aluminum layer is at least one-third the thickness of the anodized layer after anodization.

18. 14. The method of claim 13, The method of claim 1, wherein the surface of the body includes at least one opening to an internal flow passage, and the anodized layer is formed on a surface inside the internal flow passage.

19. 1. A component of a semiconductor processing chamber, comprising: A component formed by the method of claim 13.

20. 20. The component of claim 19, The component is a base plate, and further comprises a plurality of internal gas passages, each internal gas passage having a surface including an anodized layer and having an outlet on an underside of the base plate.

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