Coated components for capacitive coupling chambers - Patents.com

Abstract

An apparatus for processing a substrate is provided, the capacitively coupled plasma electrode is in a capacitively coupled plasma processing chamber, the plasma confinement component is in the capacitively coupled plasma processing chamber, and at least one of the capacitively coupled plasma electrode and the plasma confinement component includes a metal component body having a plasma-facing surface and a plasma sprayed coating thereon.

Description

[Background technology]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority to U.S. Application No. 63 / 277,282, filed November 9, 2021, which is incorporated by reference herein for all purposes.

[0002] The Background Art provided 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 manner that is not prior art at the time of filing.

[0003] FIELD OF THE DISCLOSURE The present disclosure relates to capacitively coupled plasma processing apparatus. In particular, the present disclosure relates to components or methods of providing components for use in capacitively coupled plasma processing apparatus.

[0004] Capacitively coupled plasma processing equipment has a plasma-facing surface that is exposed to voltages that corrode the plasma-facing surface. As a result, many capacitively coupled plasma processing equipment have plasma-facing surfaces that are silicon, because the corrosion of silicon forms volatile by-products that do not impair the process. The corrosion of the plasma-facing surface requires periodic replacement of parts of the capacitively coupled plasma processing equipment. Additionally, the corrosion of the plasma-facing surface can cause process drift. Summary of the Invention

[0005] To achieve the foregoing in accordance with the objectives of the present disclosure, an apparatus is provided for processing a substrate, a capacitively coupled plasma electrode is in a capacitively coupled plasma processing chamber, a plasma confinement component is in the capacitively coupled plasma processing chamber, and at least one of the capacitively coupled plasma electrode and the plasma confinement component includes a metal component body having a plasma-facing surface and a plasma sprayed coating on the plasma-facing surface.

[0006] In another embodiment, a method is provided for forming and using a plasma confinement component for a capacitively coupled plasma processing chamber. A metal component body has a plasma-facing surface. A coating is plasma sprayed onto the plasma-facing surface.

[0007] These and other features of the present disclosure will be described in more detail in conjunction with the following detailed description and the following figures. [Brief description of the drawings]

[0008] The present disclosure is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, in which like reference numbers refer to similar elements and in which:

[0009] [Figure 1] 1 is a flowchart of one embodiment.

[0010] [Figure 2A] 1 is a schematic cross-sectional view of a part formed in accordance with one embodiment. [Figure 2B] 1 is a schematic cross-sectional view of a part formed in accordance with one embodiment. [Figure 2C] 1 is a schematic cross-sectional view of a part formed in accordance with one embodiment. [Figure 2D] 1 is a schematic cross-sectional view of a part formed in accordance with one embodiment.

[0011] [Diagram 3] 1 is a diagram of a plasma processing chamber that may be used in one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] 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 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 configurations have not been described in detail in order not to unnecessarily obscure the present disclosure.

[0013] Capacitively coupled plasma (CCP) processing equipment has a plasma-facing surface that is exposed to voltages that corrode the plasma-facing surface. As a result, many capacitively coupled plasma processing equipment have plasma-facing surfaces that are silicon because the corrosion of silicon forms volatile by-products that can be evacuated instead of impairing the process. The corrosion of the plasma-facing surface requires periodic replacement of parts of the capacitively coupled plasma processing equipment and causes process drift.

[0014] Also, the roughness of silicon surfaces cannot be easily controlled and maintained. If the surface roughness of the plasma-facing surface of the component can be controlled and maintained, the surface roughness may be tailored to increase adhesion of deposits on the surface. Such deposits may be polymer by-products formed in the plasma process. Increasing adhesion of deposits on the surface reduces flaking and contamination from the deposits, thereby reducing defects.

[0015] In an inductively coupled plasma processing chamber, the coating is exposed to much lower voltages than the coating in a CCP processing chamber, where the components are exposed to high voltages of 100 eV to 400 eV, which is expected to erode the plasma-facing surfaces of the components.

[0016] Aluminum is a lightweight, inexpensive, conductive material for forming chamber components. However, aluminum can be a contaminant that increases defects in the resulting semiconductor devices. Aluminum-containing parts with plasma-facing surfaces have been avoided for CCP plasma processing chambers because of the expected corrosion of the plasma-facing surfaces of CCP plasma processing chambers.

[0017] Previously, yttria-containing coatings were avoided to protect components in capacitively coupled plasma processing equipment because yttria does not form volatile by-products and therefore yttria-containing coatings exposed to high voltages would corrode, forming yttria particles that would impair the plasma process. Also, exposure of yttria to fluorine-containing plasmas would corrode the yttria.

[0018] The CCP processing chamber has plasma confinement components. Such plasma confinement components have plasma-facing surfaces that help confine and / or direct the plasma flow. Such plasma confinement components may include electrodes, confinement rings, and various types of liners (e.g., high flow liners and / or C-shrouds). Some of the plasma confinement components in the CCP processing chamber are made of silicon and are consumables because the plasma corrodes silicon. The corrosion of the components creates process drift and increases the cost of ownership because the consumables must be replaced. Also, the surface roughness of the components changes as the components corrode. An embodiment provides a CCP processing chamber with plasma confinement components that have a higher etch resistance. The electrodes used for capacitive coupling may be exposed to the plasma as well, and are subject to corrosion and deposition of by-products. When the electrodes are above the substrate, the by-products deposited on the electrodes will flake off and fall onto the substrate, resulting in contamination.

[0019] FIG. 1 is a flow chart of one embodiment for ease of understanding. A metallic component body, such as aluminum, is provided (step 104). The aluminum component body is made of pure aluminum or an aluminum alloy (e.g., aluminum 6061). By way of example, FIG. 2A is a schematic cross-sectional view of a portion of an aluminum component body 204 of a component 208. In this example, the aluminum component body 204 is part of a C-shroud of a CCP processing system. The aluminum component body 204 is made of aluminum 6061. The aluminum component body 204 has a plasma-facing surface 212. If necessary, grit blasting of the plasma-facing surface 212 may be used to increase adhesion of the plasma-facing surface 212.

[0020] Next, an unsealed anodized layer is formed on the plasma-facing surface 212 of the aluminum component body 204 (step 108). In this embodiment, the formation of the unsealed anodized layer (step 108) involves a Type III anodizing process (also called hard anodizing or hardcoat anodizing), in which the aluminum component body 204 is exposed to a sulfur bath at a temperature between 0° C. and 3° C. and high voltage (up to 100 V) to form an oxide or "anodized" layer. The hard anodizing process forms an anodized layer 224 with a thickness of up to about 50 μm or greater, as shown in FIG. 2B. The anodized layer 224 is not shown to scale for clarity. In this embodiment, water sealing or other hydrothermal or precipitation means are not performed after anodizing, as such sealing would likely result in cracking or degradation due to the plasma process.

[0021] In some embodiments, the anodized layer 224 is at least 10 μm thick and can be as thick as 100 μm. In other embodiments, the anodized layer 224 has a thickness between 20 μm and 50 μm. In further embodiments, the anodized layer 224 has a thickness between 25 μm and 35 μm.

[0022] In one embodiment, the anodized layer 224 is an aluminum oxide layer comprising aluminum oxide with a purity of at least 99% by weight. In another embodiment, the anodized layer 224 is an aluminum oxide layer comprising aluminum oxide with a purity of at least 99.5% by weight. In yet another embodiment, the anodized layer 224 is an aluminum oxide layer comprising aluminum oxide with a purity of at least 99.9% by weight. The anodized layer 224 has a porosity of 0.5% by volume or less. In some embodiments, the porosity of the anodized layer 224 is between 0.1% and 0.5% by volume.

[0023] A plasma spray coating is then deposited on the unsealed anodized layer (step 112). In this embodiment, the plasma spray coating forms a yttrium aluminum oxide coating. Plasma spraying, also known as thermal spraying, is a coating process in which a potential is applied between two electrodes to form a blowtorch, resulting in the ionization of an accelerating gas (plasma). This type of blowtorch can easily reach temperatures of several thousand degrees Fahrenheit and liquefy high melting point materials such as ceramics. In the plasma spray head, particles of the desired material (in this embodiment, yttrium aluminum oxide particles) are injected into a nozzle, melted, and accelerated toward the substrate such that the molten or plasticized material coats the surface of the part and cools to form a solid conformal coating. These processes differ from deposition processes, which use vaporized material rather than molten material. In this embodiment, the plasma spray coating is a crystalline yttrium aluminum garnet (Y3Al5O 12 In some embodiments, the plasma spray coating further comprises a mixture of yttrium aluminum monoclinic (Y4Al2O9 (YAM)) or yttrium aluminum perovskite (YAlO3 (YAP)). In general, the yttrium aluminum oxide coating may include any yttrium aluminum oxide material (e.g., at least one of YAG, YAM, and YAP).

[0024] 2C is a schematic cross-sectional view of a portion of an aluminum component body 204 of a component 208 having an anodized layer 224 and a plasma sprayed coating 228 thereon. In this embodiment, the plasma sprayed coating 228 has a thickness inclusive of 50 μm to 200 μm and a roughness inclusive of 2 μm to 10 μm RA.

[0025] After the plasma spray coating 228 is deposited on the plasma-facing surface 212 using plasma spraying, the component 208 may be subjected to additional processing, such as cleaning (step 114). In some embodiments, the cleaning may be at least one of wet cleaning, blasting, or applying energy (e.g., ultrasonic or megasonic energy). In this embodiment, the component 208 is attached to another component to form a C-shroud. FIG. 2D is a schematic cross-sectional view of a portion of an aluminum component body 204 of the component 208 having an anodized layer 224 and a plasma sprayed coating 228 thereon, the component 208 being mechanically connected to a second C-shroud component 240. The second C-shroud component 240 is a bottom C-shroud component. In this embodiment, the second C-shroud component 240 includes an aluminum component body 244. An anodized layer 248 is formed on the plasma-facing surface of the aluminum component body 244. A plasma sprayed coating 252 is deposited on the anodized layer 248. The plasma spray coating 272 is applied before the component 208 is mechanically connected to the second C-shroud component 240 so that a plasma spray head has access to apply the plasma spray coating.

[0026] In this embodiment, one or more bolts 256 are used to mechanically connect the part 208 to the second C shroud 240. A ridge 258 is placed in front of where the part 208 is attached to the second C shroud part 240. The ridge 258 prevents a line of sight gap between the plasma region and the seam between the part 208 and the second C shroud part. The non-plasma facing surface of the second C shroud part 240 is an exposed surface 260. The exposed surface 260 is used to electrically connect the aluminum part body 244 to ground. A portion of the non-plasma facing surface of the part 208 is also exposed to connect the aluminum part body 204 to ground.

[0027] In this embodiment, the second C-shroud component 240 has a number of openings. A cross-sectional view of the openings 264 is shown in FIG. 2D. The openings 264 allow process gases, ions, and possibly some ions to flow from the plasma region to the exhaust. The openings 264 may be slots or holes. In the aluminum component body 244, small holes with high aspect ratios of depth to width may be formed in the aluminum component body 244. In this embodiment, the sidewalls of the openings 264 are coated with the anodized layer 248 and the plasma spray coating 252 to form the opening sidewall coating 268. In the plasma spray coating process, the sidewalls of the openings may not be adequately coated. Such a plasma spray coating may provide a thicker coating near its source and a thinner coating farther away, or no coating may be provided. In this embodiment, the plasma spray coating is applied from both the plasma-facing side and the opposite side. As a result, a plasma spray coating 272 is formed on the non-plasma facing surface of the second C shroud component 240. Masking may be used to provide the exposed surface 260. In various embodiments, the openings 264 may have a width of 0.01 to 5 mm. In other embodiments, the openings may have a width of 2 to 10 mm. In other embodiments, the non-plasma facing surface is not coated. In some embodiments, a portion of the non-plasma facing surface is not coated, but is anodized along with other portions of the non-plasma facing surface that are exposed.

[0028] The part 208 is mounted in the CCP processing chamber (step 116). FIG. 3 is a schematic diagram of a plasma processing system in which the part may be mounted. In one or more embodiments, the plasma processing system 300 includes a gas distribution plate 306 that provides gas inlets and an electrostatic chuck (ESC) 308 in a CCP processing chamber 309 surrounded by chamber walls 350. Inside the CCP processing chamber 309, a substrate is placed on the ESC 308. The ESC 308 serves as a substrate support. The ESC 308 may provide a bias from an ESC source 348. A gas source 310 is connected to the CCP processing chamber 309 through the gas distribution plate 306. An ESC temperature controller 351 is connected to the ESC 308 and provides temperature control of the ESC 308. In this example, a first connection 313 provides power to an internal heater 311 for heating an internal zone of the ESC 308. A second connection 314 provides power to an external heater 312 for heating an external zone of the ESC 308. The RF source 330 provides RF power to the lower electrode 334 and the upper electrode. In this embodiment, the upper electrode is the gas distribution plate 306 and is grounded. This embodiment also has an external upper electrode 345, which is grounded. The lower electrode is the ESC 308, which is a capacitively coupled plasma electrode. In a preferred embodiment, 13.56 megahertz (MHz), 2 MHz, 60 MHz, and / or 27 MHz power sources, as appropriate, comprise the RF source 330 and the ESC source 348. A controller 335 is controllably connected to the RF source 330, the ESC source 348, the exhaust pump 320, and the gas source 310. The high flow liner is a liner inside the CCP processing chamber 309. In this embodiment, the high flow liner is a C-shroud, which includes the part 208 and the second C-shroud part 240. The high flow liner confines the gas from the gas source. The high flow liner has openings 264 for maintaining a controlled flow of gas passing from the gas source 310 to the exhaust pump 320. An example of such a CCP processing chamber is the Exelan Flex™ Etch System manufactured by Lam Research Corporation of Fremont, Calif. In this embodiment, there is no inductive coupling.

[0029] The part 208 is used to process a substrate as part of a CCP processing chamber 309. In this embodiment, the substrate is processed by providing a plasma etch that deposits a passivation layer (step 120). A plasma 365 is formed by providing an etchant and a polymerizing gas of a process gas and activating the gas using a capacitively coupled plasma radio frequency (RF) power to generate a plasma. In this embodiment, the plasma process simultaneously deposits a film on the coating and etches the stack. In this example, a high aspect ratio etch is provided and a polymer-containing sidewall deposition is used. The plasma etch process provides a polymer-containing sidewall deposition so that some of the polymerizing sidewall deposition gas deposits on the plasma sprayed coating 228, forming a deposited film that includes a polymer. In some embodiments, the deposition and etching steps are repeated multiple times in a cyclical manner.

[0030] For high aspect ratio memory stacks (e.g., silicon oxide, silicon nitride, silicon oxide, silicon nitride alternating layers (ONON)), high voltage etching is used in conjunction with deposition of a passivation layer. The high voltage etching will etch the silicon components and the plasma sprayed coating 228. Etching of the plasma sprayed coating 228 will generate metal contaminant particles. However, in this embodiment providing a polymer-containing deposit on the plasma sprayed coating 228, the coating prevents or reduces erosion of the plasma sprayed coating 228 during etching. Thus, this embodiment provides a method and apparatus for providing high aspect ratio etching of stacks using a high voltage CCP with a plasma-facing surface having a yttria coating, with little or no erosion of the plasma sprayed coating and low or no contamination. In some embodiments, the high aspect ratio etching is performed at cryogenic temperatures (e.g., temperatures at which the substrate is cooled below -10°C). In some embodiments, the substrate is cooled to cryogenic temperatures of -80°C to -20°C during etching. At very low temperatures, by-product adhesion becomes more of a problem. At such temperatures, by-products do not adhere to chamber parts, resulting in more peeling and contamination. Some embodiments provide improved roughness tuning and improved erosion resistance over silicon parts to maintain roughness over time. In some embodiments, the roughness is tuned to increase adhesion of by-products to reduce contamination. With increased adhesion to reduce contamination, some embodiments may be used to etch stacks having 200 or more alternating layers.

[0031] Inductively coupled plasma processing does not require film deposition during the etching process to protect the coating. Coatings in an inductively coupled plasma processing chamber are exposed to much lower voltages than coatings in a CCP processing chamber. Coatings in a CCP processing chamber are exposed to high voltages of 100 eV to 400 eV, which would erode plasma sprayed coatings and generate particulate contamination. Such coatings would not erode in an inductively coupled plasma processing chamber. It has been unexpectedly discovered that a deposited film during etching provides sufficient protection for plasma sprayed coatings when used in a CCP process where the plasma-facing surface is exposed to electrostatic potential voltages greater than about 100 eV.

[0032] In some embodiments, other plasma-facing surfaces of plasma confinement components of the CCP processing chamber (e.g., the plasma-facing surface of a grounded electrode such as the outer upper electrode 345) may be coated with the unsealed anodized layer 224 and the plasma sprayed coating 228. In some embodiments, the outer upper electrode 345 and the gas distribution plate 306 each comprise an aluminum electrode body having a plasma-facing surface and a plasma sprayed coating thereon.

[0033] In some embodiments, plasma confinement components such as a C-shroud are placed closer to the wafer and electrode. In some embodiments, the C-shroud is placed closer to the wafer or electrode than the chamber walls are to the C-shroud. Such plasma confinement allows for the use of lower ion energies during processing, but at the same time, the plasma confinement components are exposed to higher energy ions than the chamber walls.

[0034] Currently, the plasma confinement components of such CCP processing chambers are made of silicon. The reason for making such components from silicon is that such components corrode due to exposure to high voltages. If silicon components corrode during silicon wafer etching process, the corrosion of silicon components does not create contamination during substrate processing. Silicon components corrode and are consumables that must be replaced periodically. Consumable silicon components increase the cost of ownership and increase downtime during replacement of consumable silicon components. Also, the corrosion of consumable silicon components creates process drift. To protect the silicon components, a precoat may be applied before each wafer is inserted into the chamber, and then a cleaning process may be used to remove the residual precoat after the wafer is removed from the chamber. Using a precoat process and a cleaning process for each wafer reduces throughput.

[0035] Replacement of the consumable silicon parts with aluminum parts having an unsealed anodized layer 224 and a plasma sprayed coating 228 that is more resistant to erosion in the CCP processing chamber allows replacement of the consumable parts with longer lasting parts. Extending the life of the parts or providing parts that last the life of the CCP chamber will reduce the cost of ownership and will also reduce downtime. Also, removing the consumable parts will reduce process drift. Furthermore, the surface roughness will have a longer life because the parts are more resistant to erosion. If the replacement parts include metals such as aluminum and yttrium and corrode, the corroded aluminum and yttrium will impair the processing of the substrate. To prevent such contamination, various embodiments provide parts that are more resistant to etch erosion. In various embodiments, the grounded parts are not corroded. If the plasma sprayed coating 228 is yttria (Y2O3) rather than yttrium aluminum oxide, such yttria coatings will more easily form yttrium fluoride (YF3) flakes. The YF3 particles are a source of contamination and cause process drift. In some embodiments, ungrounded parts exposed to bias corrode at a faster rate because they are exposed to higher voltages.

[0036] In other embodiments, the plasma spray coating 228 includes spinel (cubic MgAl2O4) and / or lanthanum zirconium oxide (LZO). In other embodiments, the plasma spray coating is applied to a non-anodized surface of the aluminum component body. In some embodiments, the plasma spray coating is applied to a non-anodized surface of the aluminum component body having a native oxide layer on the surface of the aluminum component body. In some embodiments, a plasma spray coating of at least one of yttria, yttrium fluoride, yttrium oxyfluoride, and magnesium fluoride may be provided on the aluminum component body. The plasma spray coating provides a more easily processed textured surface that provides improved deposition adhesion and improved erosion resistance on the silicon component body.

[0037] In various embodiments, the plasma sprayed coating 224 has a thickness including 50 μm to 200 μm and a roughness including 2 μm to 10 μm RA. The roughness may be used to promote adhesion of the polymer by-product to the surface. The increased roughness may be used to increase adhesion of the polymer by-product to the surface. The increased adhesion prevents the polymer from flaking off and becoming a contaminant. The increased adhesion may also be used to increase protection of the plasma sprayed coating 228 by the polymer to prevent or reduce corrosion. In other embodiments, the plasma sprayed coating 224 has a thickness including 60 μm to 90 μm and a roughness including 4 μm to 8 μm RA.

[0038] Although the present disclosure has been described in terms of several preferred embodiments, there are changes, modifications, permutations, and various substitute equivalents that fall within the scope of the present disclosure. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present disclosure. Therefore, the following appended claims are intended to be construed to include all such changes, modifications, permutations, and various substitute equivalents that fall within the true spirit and scope of the present disclosure. The expression "A, B, or C" as used herein should be construed to mean a logic using a non-exclusive logical "OR" ("A OR B OR C"), and should not be construed to mean "only one of A or B or C". Each step in a process is optional and not required. Different embodiments may omit one or more steps or provide steps in a different order. Also, various embodiments may provide different steps simultaneously rather than sequentially.

Claims

1. 1. A component for use in a plasma processing chamber, comprising: a metal component body having a plasma-facing surface; an anodized layer on the plasma-facing surface of the metal component body, the anodized layer being an unsealed anodized layer; A plasma spray coating on the anodized layer, comprising yttrium aluminum oxide, spinel (cubic MgAl ２ O ４ a plasma spray coating comprising at least one of: A part that includes:

2. 10. The component of claim 1, The part, wherein the plasma spray coating has a thickness comprised between 50 μm and 200 μm and a roughness comprised between 2 μm and 10 μm RA.

3. 10. The component of claim 1, The component is grounded.

4. 10. The component of claim 1, A component, wherein the metal component body comprises aluminum or an aluminum alloy, and a portion of the surface of the metal component body is not covered by the anodized layer and the plasma sprayed coating to ground the component.

5. 10. The component of claim 1, The metal component body is electrically and mechanically connected to a second metal component body.

6. 10. The component of claim 1, The metal component body includes aluminum or an aluminum alloy, the metal component body has a plurality of openings including sidewalls, and the surfaces of the sidewalls are covered with the anodized layer and the plasma sprayed coating.

7. 10. The component of claim 1, The metal component body is part of a capacitively coupled plasma processing chamber.

8. 1. A method for forming and using a component for a plasma processing chamber, comprising: providing a metal component body having a plasma-facing surface; forming an anodized layer on the plasma-facing surface of the metal component body, the anodized layer being unsealed; Plasma spraying a coating onto the anodized layer, the anodized layer being unsealed, the plasma spraying comprising yttrium aluminum oxide, spinel (cubic MgAl ２ O ４ ), and lanthanum zirconium oxide (LZO); A method comprising:

9. 9. The method of claim 8, The method wherein the coating has a thickness comprised between 50 μm and 100 μm and a roughness comprised between 2 μm and 10 μm RA.

10. 9. The method of claim 8, The method of claim 1, wherein the metal component body is comprised primarily of aluminum or an aluminum alloy.

11. 9. The method of claim 8, further comprising: The method includes mechanically connecting the metal component body with a second metal component body.

12. 9. The method of claim 8, further comprising: The method includes mounting the component as part of a capacitively coupled plasma processing chamber, wherein the component is grounded and a portion of the surface of the metal component body is not covered by the anodized layer to ground the component.

13. 13. The method of claim 12, further comprising:

10. The method of claim 1, further comprising providing a plasma etch of a stack in the capacitively coupled plasma processing chamber, the plasma etch depositing a polymer on the component and the stack while etching the stack, the component being exposed to a bias greater than 100 eV.

14. 9. The method of claim 8, The method, wherein the component is an electrode for capacitive coupling.

Images