WO2021072040A1

WO2021072040A1 - Inorganic coating of plasma chamber component

Info

Publication number: WO2021072040A1
Application number: PCT/US2020/054728
Authority: WO
Inventors: Jeremy George SMITH; David Joseph WETZEL; Slobodan Mitrovic; Robin Koshy; Ann Erickson
Original assignee: Lam Research Corporation
Priority date: 2019-10-10
Filing date: 2020-10-08
Publication date: 2021-04-15
Also published as: JP2022553646A; KR20220075426A

Abstract

A component for use in a plasma processing chamber is provided. A component body is made of a conductive material. A first ceramic coating of a first ceramic material is on a surface of the component body, wherein the first ceramic coating has a first side adjacent to the component body and a second side spaced apart from the component body and wherein the first ceramic material is a dielectric material. A second ceramic coating of a second ceramic material is on the second side of the first ceramic coating, wherein a gap is between the first ceramic coating and the second ceramic coating, wherein the gap is filled with at least one of a polymer material or a gas and wherein the second ceramic material is a dielectric material.

Description

INORGANIC COATING OF PLASMA CHAMBER COMPONENT

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of priority of U.S. Application No. 62/913,619, filed October 10, 2019, which is incorporated herein by reference for all purposes.

BACKGROUND

[0002] The background description provided here is for the purpose of generally presenting the context of the present disclosure. Anything described in this background section, and potentially aspects of the written description, are not expressly or impliedly admitted as prior art with respect to the present application. [0003] The present disclosure relates to the manufacturing of semiconductor devices. More specifically, the disclosure relates to coating chamber surfaces used in manufacturing semiconductor devices.

[0004] During semiconductor wafer processing, plasma processing chambers are used to process semiconductor devices. Coatings are used to protect chamber surfaces.

[0005] In forming semiconductor devices, plasma processing chambers are used to process the substrates. Some plasma processing chambers have aluminum alloy parts, such as liners in the plasma processing chamber. Such components may be aluminum to provide electrical and thermal characteristics that are useful in maintaining the plasma. Aluminum also allows a reduction in weight and cost. Such aluminum parts may be eroded by the plasma used during the plasma processing. A coating may be used to protect the aluminum component.

[0006] Ceramic coatings are formed over plasma processing chamber components to provide protection from plasma erosion. Such coatings may be subject to stress due to coefficient of thermal expansion mismatch and fluorination due to exposure to fluorine plasmas, resulting in part failure or the production of contaminants from the part. Typically, the coefficient of thermal expansion (CTE) is greater for an aluminum ESC body than for a ceramic protective coating. A difference in CTE between an ESC body and protective coating may cause cracking of the protective coating. SUMMARY

[0007] To achieve the foregoing and in accordance with the purpose of the present disclosure, a component for use in a plasma processing chamber is provided.

A component body is made of a conductive material. A first ceramic coating of a first ceramic material is on a surface of the component body, wherein the first ceramic coating has a first side adjacent to the component body and a second side spaced apart from the component body and wherein the first ceramic material is a dielectric material. A second ceramic coating of a second ceramic material is on the second side of the first ceramic coating, wherein a gap is between the first ceramic coating and the second ceramic coating, wherein the gap is filled with at least one of a polymer material or a gas and wherein the second ceramic material is a dielectric material. [0008] In another manifestation, a method for coating a component body for use in a plasma processing chamber is provided. A first ceramic coating is formed on a surface of the component body, wherein the first ceramic coating has a first side adjacent to the component body and a second side spaced apart from the component body, wherein the component body is of a conductive material and the first ceramic coating is of a dielectric material. A polymer layer is formed over the second side of the first ceramic coating, wherein the polymer layer has a first side adjacent to the second side of the first ceramic coating and a second side spaced apart from the first ceramic coating. A second ceramic coating is formed on the second side of the polymer layer, wherein the second ceramic coating is of a dielectric material.

[0009] In another manifestation, a method for coating a component body for use in a plasma processing chamber is provided. A ceramic coating is formed on a surface of the component body, wherein the component body is of a conductive material and the ceramic coating is of a dielectric material. A compression layer is formed in the ceramic coating through an ion exchange process.

[0010] In another manifestation, a component for use in a plasma processing chamber is provided. A component body is made of a conductive material. A diamond like carbon coating is on a surface of the component body. A ceramic coating is over the diamond like carbon coating.

[0011] In another manifestation, a method for coating a component body for use in a plasma processing chamber is provided. A diamond like carbon coating is formed on a surface of the component body, wherein the component body is of a conductive material. A ceramic coating is deposited on the diamond like carbon coating.

[0012] In another manifestation, a method for coating a component body for use in a plasma processing chamber is provided. A metal oxide coating is deposited on the component body by providing at least one of metal oxide chemical vapor deposition or plasma-enhanced vapor deposition at a temperature of less than 300° C.

[0013] These and other features of the present disclosure will be described in more detail below in the detailed description of the disclosure and in conjunction with the following figures.

BRIEF DESCRIPTION OF THE DRAWINGS [0014] The present disclosure is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:

[0015] FIG. 1 is a high level flow chart of an embodiment.

[0016] FIGS. 2A-D are schematic views of a substrate processed according to the embodiment shown in FIG. 1.

[0017] FIG. 3 is a schematic view of a plasma processing system that may be used in an embodiment.

[0018] FIG. 4 is a high level flow chart of another embodiment.

[0019] FIGS. 5A-B are schematic views of a substrate processed according to the embodiment shown in FIG. 4.

[0020] FIG. 6 is a high level flow chart of another embodiment.

[0021] FIGS. 7A-B are schematic views of a substrate processed according to the embodiment shown in FIG. 6.

[0022] FIG. 8 is a high level flow chart of another embodiment.

[0023] FIG. 9 is a schematic view of a substrate processed according to the embodiment shown in FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0024] The present disclosure will now be described in detail with reference to a few preferred embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one 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 not unnecessarily obscure the present disclosure.

[0025] For an electrostatic chuck (ESC) in a plasma processing chamber, plasma conditions cause erosion of the ESC. A protective coating may be applied to the surface of the ESC. Typically, the coefficient of thermal expansion (CTE) is greater for an aluminum ESC body than for a ceramic protective coating. A difference in CTE between an ESC body and protective coating may cause cracking of the protective coating.

[0026] Several embodiments will be provided to provide an improved protective coating. To facilitate understanding of an embodiment, FIG. 1 is a high level flow chart of a process used in an embodiment of coating a component body. A component body is provided (step 104). In this example, the component body is made of an electrically conductive material, such as aluminum with an anodized surface. A first ceramic coating of a ceramic material is applied on a surface of the component body (step 108). FIG. 2A is a schematic cross-sectional view of part of a component body 204 with a first ceramic coating 208 on a surface of the component body 204. In this embodiment, the first ceramic coating 208 is deposited by a thermal spray deposition. In other embodiments, the first ceramic coating may be deposited by plasma vapor deposition (PVD), chemical vapor deposition (CVD), or aerosol deposition. In this embodiment, the ceramic material is yttria. The component body 204 is on a first side of the first ceramic coating 208.

[0027] Thermal spraying is a general term used to describe a variety of coating processes, such as plasma spraying, arc spraying, flame/combustion spraying, and suspension spraying. All thermal spraying uses energy to heat a solid to a molten or plasticized state. The molten or plasticized material is accelerated towards the substrate so that the molten or plasticized material coats the surface of the substrate and then cools. These processes are distinct from vapor deposition processes, which use vaporized material instead of molten material. In this embodiment, the thickness of the ceramic coating is 25 to 500 microns. The first ceramic coating has a porosity in the range of 0.5% to 20%. In the specification and claims, porosity is measured according to the standard test method of ASTM E2109-01(2014).

[0028] A polymer layer of a polymer material is deposited on the first ceramic coating 208. The polymer may be deposited by at least one of atomic layer deposition (ALD), chemical vapor deposition (CVD), Plasma vapor deposition (PVD), plasma- enhanced vapor deposition (PEVD), a spin on process, or other polymer deposition methods. FIG. 2B is a schematic cross-sectional view of part of the component body 204 with the first ceramic coating 208 after the polymer layer 212 has been deposited. In this embodiment, the polymer layer 212 is formed from parylene. In this embodiment, the polymer layer 212 has a thickness of 25 to 500 microns.

[0029] A second ceramic coating of the ceramic material is deposited over the polymer layer 212 (step 116). In this embodiment, the second ceramic coating is deposited is by a chemical vapor deposition (CVD). In other embodiments, the second ceramic coating may be deposited by plasma vapor deposition (PVD) or aerosol deposition. In this embodiment, the ceramic material is yttria. In this embodiment, the thickness of the second ceramic coating is 25 to 500 microns. The second ceramic coating has a porosity of less than 0.5%.

[0030] FIG. 2C is a schematic cross-sectional view of part of the component body 204 after the second ceramic coating 216 has been deposited (step 116). In this example, the second ceramic coating 216 surrounds the polymer layer 212 and extends to the first ceramic coating 208.

[0031] The polymer layer 212 is removed (step 120). In this embodiment, a bum gas comprising oxygen is provided. The bum gas is transformed into a plasma. The plasma burns and removes the polymer layer 212, leaving an air gap. FIG. 2D is a schematic cross-sectional view of part of the component body 204 after the polymer layer 212 has been burned (step 120) leaving a gap 220. In other embodiments, the polymer layer 212 is melted away.

[0032] The component is mounted as part of a plasma processing chamber (step 124). In this embodiment, the component is an electrostatic chuck (ESC). FIG. 3 is a schematic view of a plasma processing chamber 300 for plasma processing substrates, in which the component may be installed in an embodiment. In one or more embodiments, the plasma processing chamber 300 comprises a gas distribution plate 306 providing a gas inlet and the ESC component 316, within a plasma processing chamber 304, enclosed by a chamber wall 350. Within the plasma processing chamber 304, a substrate 307 is positioned on top of the ESC component 316. The ESC component 316 may provide a bias from an ESC power source 348. A gas source 310 is connected to the plasma processing chamber 304 through the gas distribution plate 306. An ESC temperature controller 351 is connected to the ESC component 316 and provides temperature control of the ESC component 316. A radio frequency (RF) power source 330 provides RF power to the ESC component 316 and an upper electrode. In this embodiment, the upper electrode is the gas distribution plate 306. In a preferred embodiment, 400 kilohertz (kHz), 13.56 megahertz (MHz), 1 MHz, 2 MHz, 60 MHz, and/or optionally, 27 MHz power sources make up the RF power source 330 and the ESC power source 348. A controller 335 is controllably connected to the RF power source 330, the ESC power source 348, an exhaust pump 320, and the gas source 310. A high flow liner 360 is a liner within the plasma processing chamber 304, which confines gas from the gas source and has slots 362. The slots 362 maintain a controlled flow of gas to pass from the gas source 310 to the exhaust pump 320. An example of such a plasma processing chamber is the Flex^® etch system manufactured by Lam Research Corporation of Fremont, CA. In various embodiments, the process chamber can be a CCP (capacitively coupled plasma) reactor or an ICP (inductively coupled plasma) reactor.

[0033] The plasma processing chamber 304 uses the ESC component 316 to plasma process the substrate 307 (step 128). The plasma processing may be one or more processes of etching, depositing, passivating, or another plasma process. The plasma processing may also be performed in combination with nonplasma processing. Such processes may expose the ESC component 316 to plasmas containing halogen and/or oxygen.

[0034] Various components of the plasma processing chamber 304 use an electrically conductive metal base material coated with a dielectric material such as aluminum oxide or yttrium oxide deposited in a thermal or plasma spray process.

Such components include ESC’s, pinnacles, liners, gas distribution plates 306, among others. [0035] The integrity of the dielectric coating is crucial to maintain both electrical standoff and chemical resistance. Thicker dielectric ceramic coatings are more susceptible to cracking. Thinner dielectric layers do not provide sufficient insulation to prevent damage caused by the voltage used by the plasma processing chamber 304. The use of two thin ceramic coatings of the first ceramic coating 208 and the second ceramic coating 216 reduces cracking with respect to thicker ceramic coating. In addition, the use of the gap 220 has a higher dielectric strength than the first ceramic coating 208 and the second ceramic coating 216 increasing the standoff voltage and reducing electrical damage.

[0036] In other embodiments, a wall, plugs, or pillars may be used to separate the first ceramic coating 208 from the second ceramic coating 216 after the polymer layer 212 is removed. Other embodiments may use other methods to provide supports to create the gap 220. For example, a ring may be placed on the first ceramic coating, before the polymer layer fills the ring with polymer. The gap 220 may be filled with air to act as an air gap.

[0037] In other embodiments, the polymer layer 212 is not burned away. The polymer layer 212 has a higher dielectric strength than the first ceramic coating 208 and the second ceramic coating 216. However, the polymer layer 212 would be quickly eroded by a plasma. Therefore, the second ceramic coating 216 encapsulates and protects the polymer layer 212 from plasma. Such embodiments may provide improved voltage standoff and improved thermal insulation.

[0038] In various embodiments, the first ceramic coating 208 and the second ceramic coating 216 may be formed from alumina, yttria, zirconia, stabilized zirconia, and yttrium aluminum mixtures (such as yttrium aluminum garnet), or magnesium aluminum oxide (MgA^C ) spinel. In other embodiments, the first ceramic coating 208 and the second ceramic coating 216 may be formed from rare earth materials, such as erbium oxide, dysprosium oxide, cerium oxide, gadolinium oxide, and ytterbium oxide. In some embodiments, the first ceramic coating 208 is of the same material as the second ceramic coating 216. When the first ceramic coating 208 is of the same material as the second ceramic coating 216, the first ceramic coating 208 and the second ceramic coating have the same CTE. [0039] FIG. 4 is a high level flow chart of another embodiment. A component body is provided (step 404). The component body is made of an electrically conductive material. A ceramic coating is deposited on a surface of the component body (step 408). FIG. 5A is a schematic cross-sectional view of a component body 504 after the ceramic coating 508 has been deposited on a surface of the component body 504 (step 408). In this embodiment, the component body is aluminum with an anodized surface. In this example, the ceramic coating of alumina is deposited using a thermal spray process.

[0040] A compression layer is formed in the ceramic coating 508 through an ion exchange process (step 412). In this example, the ion exchange is provided by providing a vacuum-based ion bombardment of the ceramic coating 508. The ion bombardment may be provided by providing a plasma of ions with a bias. The bias causes the ions to be accelerated to and implanted in the ceramic coating 508. FIG. 5B is a schematic cross-sectional view of a component body 504 after the compression layer 512 has been formed in the ceramic coating 508 (step 412). The ions take up more space causing compression. The component is mounted as part of a plasma processing chamber 300 (step 416). The component is used in the plasma processing chamber 300 (step 420). It has been found that a compression layer 512 may harden the ceramic coating 508, making the ceramic coating 508 more resistant to cracking caused by handling and during thermal cycling in response to stress. Therefore, the compression layer 512 helps prevent cracking caused by high temperatures.

[0041] In other embodiments, a bath may be used to provide the ion exchange. A bath temperature above a certain temperature may be used to facilitate the ion exchange. An ion exchange bath may be a molten salt bath at a temperature below the melting point of the ceramic coating 508. An alkali ion from the ceramic coating 508 may be exchanged with a larger ion from the bath causing a compressive stress. In other embodiments, a diffusion process may be used to create the compression layer 512.

[0042] FIG. 6 is a high level flow chart of another embodiment. A component body is provided (step 604). In this embodiment, the component body is an electrically conductive material, such as aluminum. A diamond-like coating is formed over a surface of the component body (step 608). An example of a process for depositing the diamond-like coating uses a combination of heat and pressure so that carbon bonded with sp² bonds are sufficiently compressed to create sp³ carbon bonds. In this embodiment, the diamond like coating is an amorphous carbon material that displays some of the properties of diamond. The phrase diamond-like carbon is known in the art. FIG. 7A is a schematic cross-sectional view of part of a component body 704 after a diamond-like carbon layer 708 is deposited on a surface of the component body 704.

[0043] A ceramic coating is formed over the diamond-like carbon layer 708 (step 612). In an embodiment, the ceramic coating is formed by atomic layer deposition or chemical vapor deposition. FIG. 7B is a schematic cross-sectional view of part of the component body 704 after the ceramic coating 712 is formed over the diamond- like carbon layer 708. The component is mounted in a plasma processing chamber 300 (step 616). The component is used in the plasma processing chamber (step 624). [0044] The diamond-like carbon layer 708 has a high dielectric strength and high physical strength. However, the diamond-like carbon layer 708 is eroded by an oxygen or halogen containing plasma. Therefore the ceramic coating 712 is provided to protect the diamond-like carbon layer 708 from erosion by an oxygen or halogen containing plasma. The ceramic coating 712 may be thin. A more nonporous ceramic coating 712 is desirable. A ceramic coating formed by atomic layer deposition or chemical vapor deposition would have such properties. In this embodiment, the thickness of the second ceramic coating is 100 nanometers to 500 microns. The second ceramic coating has a porosity of less than 0.5%.

[0045] FIG. 8 is a high level flow chart of another embodiment. A component body is provided (step 804). In this example, the component body is aluminum. A metal oxide coating is deposited on a surface of the component body (step 808). In this example, the metal oxide coating is aluminum oxide (AI2O3)_. The metal oxide is deposited by either a metal oxide chemical vapor deposition (MOCVD) or plasma- enhanced vapor deposition (PECVD) at a low temperature, instead of oxidizing the component body. In this embodiment, the formation of the metal oxide is performed at a temperature of less than 300° C. In other embodiments, the formation of the metal oxide is performed at a temperature of less than 200° C. In other embodiments, the formation of the metal oxide is performed at a temperature of less than 100° C. FIG. 9 is a schematic cross-sectional view of a component body 904 with a metal oxide coating 908. The component is mounted in a plasma processing chamber 300 (step 812). The component is used in the plasma processing chamber 300 (step 816).

[0046] While this disclosure has been described in terms of several preferred embodiments, there are alterations, permutations, modifications, and various substitute equivalents, which 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 the present disclosure. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and various substitute equivalents as fall within the true spirit and scope of the present disclosure.

Claims

CLAIMS What is claimed is:

1. A component for use in a plasma processing chamber, comprising: a component body of a conductive material; a first ceramic coating of a first ceramic material on a surface of the component body, wherein the first ceramic coating has a first side adjacent to the component body and a second side spaced apart from the component body and wherein the first ceramic material is a dielectric material; and a second ceramic coating of a second ceramic material on the second side of the first ceramic coating, wherein a gap is between the first ceramic coating and the second ceramic coating, wherein the gap is filled with at least one of a polymer material or a gas and wherein the second ceramic material is a dielectric material.

2. The component, as recited in claim 1, wherein the first ceramic coating and second ceramic coating comprise at least one of alumina, yttria, zirconia, stabilized zirconia, yttrium aluminum mixtures, erbium oxide, dysprosium oxide, cerium oxide, gadolinium oxide, magnesium aluminum oxide spinel, and ytterbium oxide.

3. The component, as recited in claim 1, further comprising at least one support between the first ceramic coating and the second ceramic coating to maintain the gap between the first ceramic coating and the second ceramic coating.

4. The component, as recited in claim 1, wherein the first ceramic material is the same as the second ceramic material.

5. A method for coating a component body for use in a plasma processing chamber, comprising: forming a first ceramic coating on a surface of the component body, wherein the first ceramic coating has a first side adjacent to the component body and a second side spaced apart from the component body, wherein the component body is of a conductive material and the first ceramic coating is of a dielectric material; forming a polymer layer over the second side of the first ceramic coating, wherein the polymer layer has a first side adjacent to the second side of the first ceramic coating and a second side spaced apart from the first ceramic coating; and forming a second ceramic coating on the second side of the polymer layer, wherein the second ceramic coating is of a dielectric material.

6. The method, as recited in claim 5, further comprising removing the polymer layer after forming the second ceramic coating.

7. The method, as recited in claim 5, wherein the first ceramic coating is of a first ceramic material and the second ceramic coating is of a second ceramic material, wherein the first ceramic material is the same as the second ceramic material.

8. A method for coating a component body for use in a plasma processing chamber, comprising: forming a ceramic coating on a surface of the component body, wherein the component body is of a conductive material and the ceramic coating is of a dielectric material; and forming a compression layer in the ceramic coating through an ion exchange process.

9. The method, as recited in claim 8, wherein the forming the compression layer comprises providing a vacuum-based ion bombardment of the ceramic coating.

10. The method, as recited in claim 8, wherein the forming the compression layer, comprises immersing the ceramic coating in a bath at a temperature sufficient to cause ion exchange or a diffusion process that implants ions in the ceramic coating.

11. A component made by the method of claim 8.

12. A component for use in a plasma processing chamber, comprising: a component body comprising a conductive material; a diamond like carbon coating on a surface of the component body; and a ceramic coating over the diamond like carbon coating.

13. The component, as recited in claim 12, wherein the ceramic coating is a dielectric coating formed by at least one of atomic layer deposition or chemical vapor deposition.

14. A method for coating a component body for use in a plasma processing chamber, comprising: forming a diamond like carbon coating on a surface of the component body, wherein the component body comprises conductive material; and depositing a ceramic coating on the diamond like carbon coating.

15. The method, as recited in claim 14, wherein the depositing the ceramic coating comprises at least one of atomic layer deposition or chemical vapor deposition.

16. A method for coating a component body for use in a plasma processing chamber, comprising depositing a metal oxide coating on the component body by providing at least one of metal oxide chemical vapor deposition or plasma-enhanced vapor deposition at a temperature of less than 300° C.

17. The method, as recited in claim 16, wherein the component body comprises aluminum and is conductive.

18. A component made by the method of claim 16.