Multilayer coating of components for workpiece handling chambers

Abstract

A processing tool comprising a processing chamber for processing a workpiece, the processing chamber comprising at least one component part coated with a multi-layer protective coating, the multi-layer protective coating comprising (a) an aluminum layer formed on the at least one component part, and (b) a ceramic coating formed on the aluminum layer. In various embodiments, the multi-layer protective coating can be applied to the at least one component part before assembling the processing chamber or at least partially in situ in the processing chamber.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to U.S. Patent Application No. 62 / 779,113, filed on December 13, 2018, which is incorporated herein by reference for all purposes. Technical Field

[0003] The present disclosure relates to workpiece processing tools and, more particularly, to protective multi-layer films applied to such tools to protect against damage caused by thermal cycling, corrosion, and potential failures caused by exposure to various chemicals used in the processing chambers. Background Art

[0004] Workpieces such as semiconductor wafers and flat panel displays are often processed during the manufacturing process using various processing tools. For example, various deposition tools are commonly used to deposit various thin films onto the workpiece surface. Similarly, various etching tools such as wet and / or plasma etching tools are also commonly used to selectively remove material layers from the workpiece surface. There are many different chemistries used in the processing chamber.

[0005] For example, using a plasma etching tool, the workpiece is typically exposed to a plasma rich in chlorine and / or fluorine. During deposition, when radio frequency (RF) is applied to one or more reactive gases (such as silane (SiH 4 ), nitrous oxide (N 2 O), ammonia (NH 4 ), nitrogen (N 2 ), plasma is generated in the process chamber. Also, materials deposited on the workpiece using deposition tools will typically also accumulate on surfaces exposed to the process chamber. In routine "dry cleaning" processes, plasmas rich in chlorine and / or fluorine can be periodically generated in the process chamber to remove these deposits. Similarly, using etching tools, chlorine and / or fluorine are often used to remove selected materials from the workpiece.

[0006] The process chambers of both etching and deposition tools are comprised of a variety of subassemblies (e.g., a showerhead, a workpiece heater, a portion of a workpiece support, etc.) and a variety of mechanical parts (e.g., clamps, screws, bolts, springs, pins, clips, or other mechanical fasteners) used to mechanically secure the various subassemblies together. In general, these subassemblies and / or mechanical parts, hereinafter collectively referred to as "component parts," are characterized by: (1) any metal part that is exposed to chemicals in the process chamber; and / or (2) being subjected to some type of mechanical stress, such as deflection caused by thermal cycling, friction, and / or contact or friction with another component part, such as in the case of clamps, springs, pins, and clips.

[0007] When these component parts are exposed to the various chemicals used in the process chamber, they can experience corrosion, which is problematic. For certain types of components, such as clamps or springs, corrosion can negatively impact their performance, meaning that over time, these parts will no longer provide the clamping force or spring force within the required specifications. Additionally, corrosion can eventually lead to component part failure. Corrosion can further lead to particle shedding. These particles can contaminate the workpiece being processed, adversely affecting the output of that process.

[0008] To mitigate the aforementioned corrosion issues, manufacturers of workpiece processing tools and / or their suppliers often overlay component parts with ceramic or aluminum. Both materials have their drawbacks due to the challenges present in the processing chamber.

[0009] Thermal mismatch between the ceramic coating and its underlying component may cause the two to expand and contract at different rates, especially during high temperature thermal cycles typically experienced in workpiece processing. The resulting mechanical stresses may cause the ceramic to crack and / or fail. Second, the ceramic coating is susceptible to scratching, flaking, and / or accidental encapsulation of particulate contaminants, all of which may cause the ceramic coating to fail. The underlying component is then exposed to chemicals that cause corrosion, which may ultimately cause the component to be out of specification and / or fail.

[0010] Aluminum coatings are often produced using an electroplating process. During electroplating, the component parts are often clamped while held in the electroplating bath. Where clamped, "holder" marks often result because minimal or even no electroplating occurs in these locations. As a result, bubbles trapped during the electroplating process may be released into the process chamber later during workpiece processing. In addition, aluminum coatings grow an aluminum fluoride layer when exposed to aluminum chemicals. Aluminum fluorides tend to generate particles. Both the release of bubbles and particle formation are problematic because they tend to contaminate the process environment within the process chamber during workpiece processing. Summary of the invention

[0011] Disclosed herein is a workpiece processing tool comprising a process chamber having at least one component part protected by a multi-layer coating that provides protection from damage caused by thermal cycling and exposure to chemicals commonly used in the process chamber. In a non-exclusive embodiment, the multi-layer coating comprises (a) an aluminum base layer formed on the at least one component part and (b) a ceramic coating formed on the underlying aluminum layer.

[0012] Multilayer coatings have many advantages. The relatively thick base aluminum layer provides mechanical protection for the underlying component parts. As a result, damage or failure caused by mechanical stress caused by thermal mismatch between the component parts and the aluminum layer during thermal cycling is greatly reduced or completely eliminated. In addition, the relatively thick aluminum layer is less susceptible to failure due to scratching, flaking and / or accidental coating of particulate contaminants. On the other hand, the ceramic layer is relatively inert to many chemicals used in the processing chamber (such as fluorine). As a result, the underlying component parts are greatly protected from corrosion, preventing or reducing component parts from being out of specification and / or failure. In addition, the ceramic layer is used to cover the bracket marks that may appear in the electroplating process of the underlying aluminum layer, thereby preventing the release of bubbles during workpiece processing.

[0013] In non-exclusive embodiments, the base layer is aluminum having a thickness of 25 microns, 250 microns, any thickness in the range of 25 to 250 microns, less than 25 microns, or greater than 250 microns. In still other embodiments, the ceramic coating is an amorphous aluminum oxide ceramic layer, a yttrium oxide layer, or a combination of the two. In other embodiments, the thickness of the ceramic layer is 1 micron or less or 10 microns or less.

[0014] In additional embodiments, the processing chamber includes one or more component parts, each of which is protected by a multi-layer coating. The one or more component parts may include (a) any metal part or parts that are exposed to the above-mentioned chemicals in the processing chamber; and / or (2) are subjected to some type of mechanical stress, such as deflection caused by thermal cycling, contact with another mechanical part, or friction. Such component parts may include, but are not limited to, a wide range of subassemblies (e.g., a showerhead, a workpiece heater, a portion of a workpiece holder, etc.) and / or various mechanical parts, such as clamps, screws, bolts, springs, pins, clips and other mechanical fasteners.

[0015] In other embodiments, the process chamber of the workpiece processing tool can be assembled in a variety of different ways. In a first embodiment, the component parts are first coated with a multi-layer coating in the following manner: (a) electroplating aluminum layer, and (b) using an atomic layer deposition (ALD) process to form a ceramic layer. Once the coating is completed, the component parts can be used to assemble the process chamber.

[0016] In an alternative embodiment that can be implemented with a deposition tool, the component part is (a) first coated with an aluminum layer using an electroplating process. Once the aluminum layer is applied, the component part is used to assemble a processing chamber. Thereafter, the component part is (b) coated with a ceramic layer in situ in the processing chamber using a deposition process.

[0017] The workpiece processing tool can be any type having a processing chamber for processing the workpiece. In a non-exclusive embodiment, the tool can be any type of deposition tool or a wet or dry etching tool. The workpiece can include a semiconductor wafer, a flat panel display, or any other type of workpiece that needs to be processed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present application and its advantages will be best understood by referring to the following description and accompanying drawings, in which:

[0019] Figure 1A and 1B FIG. 2 is a diagram of a process chamber of an exemplary deposition and etching tool that is used for workpiece processing in accordance with a non-exclusive embodiment of the present invention.

[0020] Figures 2A-2D Detailed Description of the Invention Various component parts are provided in a processing chamber according to a non-exclusive embodiment of the present invention.

[0021] Figure 3A-3B 2 is a cross-sectional view of various multi-layer coatings applied to a component part according to a non-exclusive embodiment of the present invention.

[0022] Figure 4A and 4B is a flow chart illustrating the steps of assembling a workpiece processing tool in accordance with a non-exclusive embodiment of the present invention.

[0023] In the drawings, like reference numerals are sometimes used to refer to like structural elements. It should be understood, however, that the depictions in the drawings are schematic and not necessarily drawn to scale. DETAILED DESCRIPTION

[0024] The present application will now be described in detail with reference to some non-exclusive embodiments as shown in the accompanying drawings. In the following description, many 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 implemented without some or all of these specific details. In other cases, known processing steps and / or structures are not described in detail to avoid unnecessarily obscuring the present disclosure.

[0025] Figure 1A and Figure 1B Figures are diagrams of process chambers of exemplary deposition and etch workpiece processing tools, respectively.

[0026] Reference Figure 1A, which shows a diagram of an exemplary chemical vapor deposition (CVD) tool 10. The CVD tool 10 includes a process chamber 12, a showerhead 14, a workpiece holder 16 for supporting and positioning a workpiece 18 to be processed, and a radio frequency (RF) generator 20. In many embodiments, the CVD tool can be a plasma enhanced (PECVD), low pressure (LPCVD), ultra-high vacuum (UHVCVD), atomic layer deposition (ALD), plasma enhanced atomic layer deposition (PEALD), or any other type of CVD tool.

[0027] For example, silane (SiH 4 ), nitrous oxide (N 2 O), ammonia (NH 4 ) and / or nitrogen (N 2 ) is supplied to the processing chamber 12 through the showerhead 14. In the showerhead 14, the gas is distributed to the general area above the surface of the workpiece 18 to be processed in the chamber 12 through one or more gas chambers (not shown). Then the RF potential generated by the RF generator 20 is applied to the electrode (not shown) on the showerhead 14. (The RF potential may also be applied to the workpiece holder 18). The RF potential generates a plasma 22 in the processing chamber 12. In the plasma 22, the charged electrons are ionized or dissociated (i.e., "broken") from the reactive gas, generating chemically reactive free radicals. When these free radicals react, they are deposited and form a thin film on the workpiece 18.

[0028] During workpiece processing, the processing chamber 12 will typically undergo thermal cycles. The extent of the thermal cycle is determined by several factors, including the type of workpiece, the specific chemistry used and the material to be deposited, the desired deposition rate, etc. Other factors that may also be considered are the thermal budget to prevent damage to the film, the physical and chemical properties of the film, and a general preference for using lower temperature processing when feasible.

[0029] For example, it is generally less expensive to use aluminum rather than ceramic components in the processing chamber 12. However, aluminum is easily weakened or otherwise adversely affected when the temperature exceeds 450°C. Therefore, to some extent, the use of aluminum components will limit the upper limit of the thermal cycle to about 450°C. On the other hand, ceramics are better than aluminum in terms of tolerance for elevated temperatures. In this way, the upper limit of the thermal cycle using ceramics can be higher. Therefore, it should be understood that the temperature range of a given thermal cycle can vary greatly, such as any temperature from 20°C to 450°C or even from 20°C to 800°C, depending on various factors and other considerations mentioned above. These lower and upper temperature values ​​are merely exemplary and should not be interpreted as limiting. Lower or higher temperature values ​​can be used.

[0030] As previously discussed, materials deposited on the workpiece 18 may also be inadvertently deposited on various other surfaces within the processing chamber 12. To remove these accumulated deposits, the tool 10 is typically subjected to a periodic "dry clean" procedure, in which chlorine and / or fluorine chemicals are introduced into the chamber 12 and RF power is applied to generate a plasma. In response, the deposits are etched or otherwise removed from surfaces within the chamber 12. Once the deposits are substantially removed, the tool 10 is then used again to process the workpiece 18 in the manner discussed above.

[0031] Reference Figure 1B , which shows a diagram of an exemplary plasma etching tool 30. The plasma etching tool 30 includes a processing chamber 32, a power electrode 38, and an RF power source 40 coupled to the power electrode 38. During operation, etching chemicals such as chlorine and / or fluorine are introduced into the processing chamber 32, and RF power is applied to the power electrode 38 by the RF power source 40 to generate a plasma 42. The plasma 42 etches away exposed materials on the surface of the workpiece 36, which is well known in the art.

[0032] The processing chamber 32 of the processing tool 30 is also subjected to thermal cycles. During the etching of the workpiece, the temperature inside the chamber 32 will generally increase. The thermal cycle can vary widely and also depends on a variety of factors, such as the type of workpiece, the type of material being etched, the materials of the components of the etching chamber, etc. For example, in non-exclusive embodiments, the upper limit of the thermal cycle can be 450° C. or up to 800° C. Once again, it should be understood that these values ​​are exemplary and should not be interpreted as limiting. Lower or higher temperatures can be used.

[0033] The processing chamber 10 / 30 of deposition tool 10 and etching tool 30 each comprises various components. As used herein, the term "components" is intended to be broadly interpreted as any metal parts that refer to (a) being exposed to the chemical substances in the processing chamber 10 / 30, and / or (b) being subjected to the effect of a certain type of mechanical stress, such as the deflection caused by thermal cycle, contact or friction with another mechanical part. Such components can include but are not limited to various subassemblies (such as showerheads, workpiece heaters (not shown), parts of workpiece holders, etc.) and / or various mechanical parts, such as fixtures, screws, bolts, springs, pins, clips and other mechanical fixtures. In various embodiments, the components can be made of various metals and / or alloys, including, for example, aluminum, stainless steel, ferrous alloys, Inconel 718, Nonel, Nimonic 90, Waspaloy, A286, etc.

[0034] FIG. 2A to FIG. 2D1 is a diagram of various component parts, which are arranged in a processing chamber of a workpiece processing tool according to a non-exclusive embodiment of the present invention. In these examples, Figure 2A Load distribution washers are shown. Figure 2B A retaining or "snapping" ring is shown. Figure 2C The load distributing washer is shown centered on the bearing. Figure 2D Different views of a wave spring are shown. These illustrations are exemplary only and should not be construed as limiting in any respect. In actual embodiments, the number and types of component parts that may be covered by multiple layers of protective coatings are too numerous to be practically described here.

[0035] In order to solve the corrosion, degradation and potential failure of the above-mentioned component parts, the applicant proposes to use a multi-layer coating. In a non-exclusive embodiment, the multi-layer coating comprises (a) an aluminum base layer formed on the at least one component part and (b) a ceramic coating formed on the underlying aluminum layer.

[0036] In a non-exclusive embodiment, the base aluminum layer has a thickness of 25 microns and is formed by an electroplating process. The thickness of the ceramic layer is 1 micron or less and is formed by an atomic layer deposition (ALD) process. Examples of ceramic coatings may include, but are not limited to, amorphous aluminum oxide ceramic layers (Al 2 O 3 ), yttrium oxide layer (Y 2 O 3 ), or a stack of the two. It should be understood that the materials and dimensions of the multilayer coating described in this embodiment are exemplary and should not be construed as limiting. Multilayer coatings of various materials and thicknesses can be used and selected based on their mechanical properties and / or inertness to different chemicals. For example, the thickness of the aluminum substrate layer can be less than 25 microns, between 25 and 250 microns, or greater than 250 microns. Due to the slow deposition rate of ALD and the stress present in the deposited film, the thickness of the ceramic layer commonly used is less than 1 micron. However, again, this should not be construed as limiting. For example, a layer of 10 microns or thicker can be used.

[0037] Multilayer coatings have many advantages. The relatively thick base aluminum layer provides mechanical protection for the underlying components. As a result, during thermal cycling, failures caused by mechanical stresses caused by thermal mismatch between the components and the aluminum layer are greatly reduced or completely eliminated. In addition, the relatively thick aluminum layer is less susceptible to failure due to scratches, peeling and / or accidental coating on particulate contaminants. On the other hand, the ceramic layer is inert to a variety of chemicals such as fluorine and provides protection against these chemicals. The ceramic layer protects the underlying components from corrosion and prevents granulation of the underlying aluminum. In addition, the ceramic layer covers the bracket marks that may appear during the electroplating process of the aluminum layer, thereby preventing the release of trapped bubbles.

[0038] Figure 3A-3B 5 are cross-sectional views of various multi-layer coatings applied to an exemplary component part 50 in accordance with non-exclusive embodiments of the present invention.

[0039] exist Figure 3A In the embodiment of the present invention, an aluminum layer 52 is formed on the surface of the component part 50. In various embodiments, the aluminum layer 52 is formed by electroplating and has a thickness of at least 25 microns. In alternative embodiments, the thickness of the aluminum layer can be in the range of 25 to 250 microns, less than 25 microns, or greater than 250 microns. In addition, the purity level of the aluminum can also vary. In some embodiments, high purity aluminum can be used, while in other embodiments, lower purity aluminum can be used.

[0040] exist Figure 3B , a ceramic coating 54 is formed on an underlying aluminum layer 52. In various embodiments, the ceramic coating 54 has a thickness of 1 micron or less and is formed using an atomic layer deposition (ALD) process. Examples of ceramic coatings 54 include, but are not limited to, an amorphous aluminum oxide ceramic layer, a yttrium oxide layer, or a stack of the two. In alternative embodiments, any deposition process may be used to form the ceramic coating 54, and other ceramic materials other than those listed herein may be included. In addition, the thickness may vary, for example, from 1 micron or less, 10 microns or less, or greater than 10 microns.

[0041] Figure 4A and Figure 4B is a flow chart illustrating steps for assembling a workpiece processing tool according to a non-exclusive embodiment of the present invention.

[0042] Reference Figure 4A , a flow chart 60 is shown in which multiple layers of coating of component parts are performed prior to assembling a process chamber of a tool.

[0043] The initial step 62 involves applying a multi-layer coating to one or more component parts using any of the above-described embodiments. In other words, the one or more component parts are coated with at least (a) an aluminum base layer 52 formed on at least one component part 50, and (b) a ceramic coating 54 formed on the underlying aluminum layer. Again, the term "component part" as used herein is intended to be broadly interpreted and includes, but is not limited to, any of the above-listed component parts that may be subjected to mechanical stress and / or exposure to chemicals within the processing chamber.

[0044] The process chamber of the tool is assembled at least in part using component parts having the multi-layer coating and other uncoated parts and / or subassemblies in step 64. Thereafter, the process chamber and tool are tested and made operational as is known in the art.

[0045] In step 66, the tool is used to process a workpiece such as a semiconductor wafer, a flat panel display, etc. In various embodiments, the tool may be a deposition tool for depositing a thin film onto a workpiece or may be an etching tool for selectively removing material from a workpiece.

[0046] Reference Figure 4B , shows a flow chart 70 in which multi-layer coating of component parts occurs partially prior to assembly of the process chamber of the tool and partially in situ after the process tool has been assembled and is operational. For this embodiment, only deposition tools may be used.

[0047] An initial step 72 involves partially coating one or more component parts with (a) an aluminum base layer 52 using any of the above-described embodiments.

[0048] In step 74, the processing chamber of the tool is assembled using one or more component parts coated with only the aluminum base layer 52. Thereafter, the tool is tested and made operational as is known in the art.

[0049] In step 76, the ceramic coating 54 of (b) is formed in situ in the process chamber of the tool. For example, the ceramic layer 54 is deposited onto the aluminum base layer 52 using any of the above-described embodiments using an atomic layer deposition (ALD) tool. For this embodiment, it should be understood that other exposed surfaces within the process chamber may also be coated with the ceramic material unless steps are taken to mask or otherwise prevent deposition on these surfaces.

[0050] Finally, in step 78, the tool is used to process the workpiece.

[0051] like Figure 4BAs shown, one notable advantage is the ability to re-apply the ceramic layer 54 in-situ in the process chamber from time to time. Since the process tool is used to process the workpiece, the ceramic layer 54 may degrade due to repeated exposure to various chemicals. With the ability to form the ceramic coating 54 in-situ, the one or more component parts can be periodically re-coated as part of a routine maintenance procedure, thereby eliminating the need to disassemble the process chamber and / or tool.

[0052] It should be understood that although the embodiments described herein are largely related to deposition and etching tools, this should not be construed as limiting. Instead, the subject matter described herein can be used with any type of workpiece processing tool, regardless of the type of workpiece or how the workpiece is processed.

[0053] It should be understood that the embodiments provided herein are only exemplary and should not be interpreted as limiting in any aspect. Although only several embodiments are described in detail herein, it should be understood that the application can be implemented in many other forms without departing from the spirit or scope of the disclosure provided herein. Therefore, the present embodiment should be considered to be illustrative rather than restrictive, and is not limited to the details given herein, but can be modified in the scope and equivalents of the appended claims.

Claims

1. A processing tool comprising a processing chamber for processing a workpiece, wherein the processing chamber comprises at least one component part subjected to mechanical stress having a multi-layer coating, wherein the multi-layer coating comprises (a) an aluminum mechanical protection layer formed on the at least one component part, wherein the aluminum mechanical protection layer comprises a thickness of 25 microns or more, and (b) a deposited ceramic coating formed on the aluminum mechanical protection layer, wherein the deposited ceramic coating has a thickness of 10 microns or less, wherein the deposited ceramic coating has an anti-fluorine protection effect, and wherein the at least one component part is made of an iron-containing alloy.

2. The processing tool of claim 1, wherein the deposited ceramic coating is an amorphous aluminum oxide ceramic layer.

3. The processing tool of claim 1, wherein the deposited ceramic coating is a yttrium oxide layer.

4. The processing tool of claim 1, wherein the deposited ceramic coating is a stack of amorphous aluminum oxide ceramic and yttrium oxide.

5. The processing tool of claim 1, wherein the deposited ceramic coating has a thickness of 1 micron or less.

6. The processing tool of claim 1, wherein the aluminum mechanical protection layer has a thickness of 25 microns to 250 microns.

7. The processing tool of claim 1, wherein said aluminum mechanical protection layer includes a standoff trace, and wherein said deposited ceramic coating covers said standoff trace.

8. The processing tool according to claim 1, wherein the component part is a spring, a washer or a retaining ring.

9. The processing tool of claim 1, wherein the processing tool is a deposition tool or an etching tool.

10. A method of forming at least one component part of a workpiece tool, comprising: electroplating the at least one component part to form an aluminum mechanical protection layer, the aluminum mechanical protection layer being formed on the at least one component part, the aluminum mechanical protection layer comprising a thickness of 25 micrometers or more, wherein the at least one component part is made of an iron-containing alloy; and After the electroplating, a ceramic coating is deposited by vapor deposition, wherein the ceramic coating is formed on the aluminum mechanical protective layer, wherein the deposited ceramic coating has a thickness of 10 microns or less, wherein the deposited ceramic coating has an anti-fluorine protection effect, and wherein the electroplating and the deposition are performed before assembling the processing chamber using at least one of the component parts. The method according to claim 10 , wherein the thickness of the aluminum mechanical protection layer is 25 to 250 μm.

12. The method of claim 10, wherein the deposited ceramic coating comprises one of the following: (c) an amorphous aluminum oxide ceramic layer; (d) yttrium oxide layer; (e) Laminated layers of amorphous aluminum oxide ceramic and yttrium oxide.

13. The method of claim 10, wherein the deposited ceramic coating has a thickness of 1 micron or less.

14. The method of claim 10, wherein the component part is a spring, a washer, or a retaining ring.

15. The method of claim 10, wherein the process chamber is incorporated into a deposition tool or an etching tool.

16. A method of assembling a workpiece processing tool, comprising: Assembling a process chamber using at least one component part having an aluminum mechanical protection layer formed on the at least one component part, the aluminum mechanical protection layer comprising a thickness of 25 micrometers or more, and A ceramic coating is deposited on the aluminum mechanical protective layer using atomic layer deposition (ALD), wherein the deposited ceramic coating comprises a thickness of 10 microns or less, wherein the deposited ceramic coating has an anti-fluorine protection effect, and wherein at least one of the component parts is made of an iron-containing alloy and is a spring, a washer or a retaining ring.

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