Coated substrate support assembly for substrate processing

Abstract

The embodiments of the present disclosure generally relate to a substrate support having a two-part surface coating that reduces defect formation and backside metallic contamination during substrate processing. The support body includes a body having an upper surface and a two-part coating disposed on the upper surface of the body. The two-part coating includes a first coating layer extending a first radial distance from a center of the body. The first coating layer includes at least one of a metal-containing material or an alloy. The two-part coating includes a second coating layer disposed on the first coating layer. The second coating layer extends a second radial distance from a center of the body. The first radial distance is greater than the second radial distance. The second coating layer is non-metallic.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to an apparatus for supporting a substrate during a processing operation in an electronic device manufacturing process. More particularly, the embodiments disclosed herein relate to a substrate support having a two-part surface coating that reduces defect formation and backside metal contamination during substrate processing, as well as a method of forming the coating.

Background Art

[0002] Integrated circuits are formed within and on silicon and other semiconductor substrates. In the case of single-crystalline silicon, the substrate is made by growing an ingot from a bath of molten silicon and then cutting the solidified ingot into a plurality of substrates. Next, an epitaxial silicon layer can be formed on the single-crystalline silicon substrate to form a defect-free silicon layer that may or may not be doped. Semiconductor devices such as transistors can be fabricated from the epitaxial silicon layer. The electrical properties of the formed epitaxial silicon layer are generally superior to those of the single-crystalline silicon substrate.

[0003] The surfaces of single-crystalline silicon and the epitaxial silicon layer are prone to contamination when exposed to the ambient conditions of a typical substrate manufacturing facility. For example, a native oxide layer may form on the single-crystalline silicon surface prior to the deposition of the epitaxial layer due to the handling of the substrate in a substrate processing facility and / or exposure to the surrounding environment. Further, foreign substances such as carbon and oxygen species present in the surrounding environment may deposit on the single-crystalline surface. The presence of an oxide layer or contaminants on the single-crystalline silicon surface adversely affects the quality of the epitaxial layer subsequently formed on the single-crystalline surface. Thus, a pre-cleaning process may be performed to remove the oxide layer and contaminants from the single-crystalline surface. However, in conventional pre-cleaning processes, the substrate needs to be exposed to a processing gas, which may cause surface corrosion of the substrate support. In some instances, by-products of the material resulting from the corrosion of the substrate support may contact the substrate, causing defect formation on the substrate and metal contamination on the backside.

[0004] Therefore, in the art, there is a need to provide an improved substrate support that minimizes substrate defect formation and backside metal contamination and withstands the corrosive action of the pre-cleaning process gas. SUMMARY OF THE INVENTION

[0005] The present disclosure describes a support body for supporting a substrate within a processing chamber. In some embodiments, the support body includes a body having an upper surface and a two-part coating disposed on the upper surface of the body. The two-part coating includes a first coating layer extending at a first radial distance from the center of the body. The first coating layer includes at least one of a metal-containing material or an alloy. The two-part coating includes a second coating layer disposed on the first coating layer. The second coating layer extends at a second radial distance from the center of the body. The first radial distance is greater than the second radial distance. The second coating layer is non-metallic.

[0006] In some embodiments, the system includes a processing chamber configured to clean a substrate. The processing chamber includes a chamber body, a lid assembly disposed at an upper end of the chamber body, and a substrate support assembly at least partially disposed within the chamber body and configured to support a substrate within the processing chamber. The lid assembly includes a dual-channel showerhead having a first channel set providing fluid communication above and below a plane of the showerhead and a second channel set providing fluid communication with a side port of the chamber body. The substrate support assembly includes a support body having an upper surface that extends at a first radial distance from a center of the support body. The substrate support assembly includes a stem coupled to the support body and a coating disposed on the support body. The coating includes a first coating layer disposed across the upper surface of the support body, the first coating layer including electroless nickel plating. The coating includes a second coating layer disposed on the first coating layer, the second coating layer extending at a second radial distance from a center of the support body, the second radial distance being less than the first radial distance, and the second coating layer including silicon carbide.

[0007] In some embodiments, a method of forming a surface coating on a support body of a processing chamber includes depositing a first material across an entire upper surface of the support body, thereby forming a first coating layer, the first material including at least one of a metal-containing material or an alloy. The method includes depositing a second material on the first coating layer only on a portion of the upper surface of the support body, thereby forming a second coating layer, the second material being non-metallic.

[0008] Embodiments of the present disclosure have been briefly summarized above and will be described in more detail below, but can be understood by reference to the exemplary embodiments of the present disclosure shown in the accompanying drawings. However, it should be noted that the accompanying drawings show only typical embodiments of the present disclosure and thus are not considered to limit the scope of the present disclosure as other equally effective embodiments are contemplated.

Brief Description of the Drawings

[0009]

Figure 1A

Figure 1B

Figure 1C

Figure 1D

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0010] For ease of understanding, wherever possible, the same reference numbers are used to denote the same elements common to each figure. The figures are not drawn to scale and may be simplified for clarity. It is contemplated that the elements and features of one embodiment may be beneficially incorporated into other embodiments without further elaboration.

[0011] The embodiments disclosed herein relate to a substrate support having a two-part surface coating that reduces defect formation and backside metal contamination during substrate processing, as well as a method of forming the coating.

[0012] Certain embodiments disclosed herein provide a substrate support assembly (also referred to as a "pedestal") having a two-part surface coating, as opposed to a conventional one-part coating. A first coating that can fill even the smallest feature sizes and complex structures is applied over the entire substrate support assembly to reduce corrosion across the surface of the substrate support assembly. A second coating that is free of metal contaminants is applied over the upper portion of the substrate support assembly (e.g., the support body) to reduce metal contamination on the back side of the substrate. Thus, the coating performance is improved compared to conventional one-part coatings.

[0013] In some examples, the substrate may include a silicon-containing material, and the surface may include a material such as silicon (Si), germanium (Ge), or a silicon germanium alloy (SiGe). In some examples, the Si, Ge, or SiGe surface may have an oxide layer, such as a native oxide layer, and contaminants deposited thereon. Since epitaxial deposition processes are sensitive to contaminants such as oxides and carbon-containing contaminants, surface contamination caused by exposure to a cleanroom environment for several hours can become severe enough to affect the quality of the subsequently formed epitaxial layer by the accumulated oxides and contaminants. Thus, a pre-cleaning process may be performed to remove the oxide layer and contaminants from the surface. As used herein, the term "pre-cleaning" refers to a process involving exposing the substrate (e.g., a semiconductor substrate) to one or more process gases to remove an oxide layer or contaminants from the substrate surface. In this specification, "pre-cleaning" may also be referred to as "etching".

[0014] In some examples, the substrate surface can be cleaned by performing an oxide removal process and a contaminant removal process. In one example, a pre-cleaning process can be used to remove oxides from the surface of the substrate, and a reduction process can be used to remove contaminants, such as carbon-containing contaminants, from the surface of the substrate.

[0015] In some examples, the processing gas may include a reactive gas such as a fluorine-containing gas or a chlorine-containing gas. In some examples, the processing gas may further include vapor. In some examples, the processing gas may further include one or more purge gases or carrier gases (e.g., hydrogen, helium, and / or argon). In some examples, the reactive gas may include hydrogen fluoride (e.g., HF), anhydrous hydrogen fluoride (sometimes referred to as "AHF"), diatomic fluorine (F2), nitrogen fluoride (e.g., nitrogen trifluoride (NF3)), carbon fluoride (e.g., carbon tetrafluoride (CF4), hexafluoroethane (C2F6), trifluoromethane (CHF3), difluoromethane (CH2F2), octafluoropropane (C3F8), octafluorocyclobutane (C4F8), octafluoro[1-]butane (C4F8), octafluoro[2-]butane (C4F8), or octafluoroisobutylene (C4F8)), sulfur fluoride (e.g., sulfur hexafluoride (SF6)), ammonia (NH3), or combinations thereof.

[0016] In some examples, the flow rate of the reactive gas may be from about 50 sccm to about 500 sccm for a 300 mm substrate. In some examples, the concentration of the reactive gas in the processing chamber (e.g., in contact with the substrate surface) may be from about 5% wt / wt to about 75% wt / wt of the total processing gas mixture including any other components (e.g., vapor, carrier gas, or purge gas).

[0017] In some examples, the vapor may include water (e.g., distilled water), a primary alcohol (e.g., methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, or isobutyl alcohol), a secondary alcohol (e.g., isopropyl alcohol or sec-butyl alcohol), a tertiary alcohol (e.g., tert-butyl alcohol), a cyclic alcohol (e.g., cyclohexyl alcohol), a compound alcohol (e.g., 4-ethyl-3-hexanol), a C1 alcohol, a C2 alcohol, a C3 alcohol, a C1-C2 alcohol, a C1-C3 alcohol, a C1-C4 alcohol, an organic acid, or a combination thereof. In some examples, the vapor may increase the reaction rate between the reactive gas and the surface oxide. In some examples, an alcohol with a lower carbon number can increase the reaction rate more significantly compared to an alcohol with a higher carbon number (e.g., the relative reaction rate may be C1 alcohol > C2 alcohol > C3 alcohol). In some examples, for a 300 mm substrate, the vapor flow rate may be from about 5 sccm to about 500 sccm. In some examples, the flow rate ratio of the reactive gas to the vapor may be from about 10:1 to about 1:10. In some examples, the vapor concentration may be from about 5 wt / wt to about 75 wt / wt of the total process gas mixture including any other components (e.g., reactive gas, carrier gas, or purge gas).

[0018] During operation, the reactive gas and the vapor may be provided to the processing chamber via different paths (i.e., separately), and after arriving at the processing chamber, they may be mixed before contacting the substrate. In some other examples, the reactive gas may be mixed with the vapor to fill the processing chamber. The mixing of the gases may be spatially separated from the processing region where the substrate is disposed. The term "spatially separated" as described herein may refer to a mixing region separated from the substrate processing region by one or more chamber components, or even a conduit between the mixing chamber and the substrate processing chamber. In some examples, the processing temperature, which may refer to the temperature of the mixed processing gas in the processing chamber (e.g., the temperature of the mixed processing gas contacting the substrate surface), may be about 0 °C or less, for example, from about -50 °C to about 40 °C. In some examples, the pressure in the processing chamber may be in the range of about 0.5 Torr to about 20 Torr.

[0019] Since the pre-cleaning process is mainly conformal and can be selective to the oxide layer, it does not easily etch silicon (e.g., low-k spacers or other dielectric materials), germanium, or nitride layers, regardless of whether the layer is amorphous, crystalline, or polycrystalline. In some examples, the selectivity of the processing gas for the oxide compared to silicon or germanium can be at least about 3:1, for example, about 5:1 or more, for example, about 10:1 or more. The processing gas may also have a high selectivity for the oxide compared to the nitride. In some examples, the selectivity of the processing gas for the oxide compared to the nitride can be at least about 3:1, for example, about 5:1 or more, for example, about 10:1 or more, for example, about 20:1 or more, for example, about 50:1 or more, for example, about 80:1 or more, for example, about 100:1 or more, for example, about 120:1 or more.

[0020] In some examples, thermal energy may be applied to the processed substrate either during or after the pre-cleaning process to assist in the removal of the generated by-products. In some examples, the thermal energy may be provided via radiation, convection, and / or conduction heat transfer processes that sublime the undesirable by-products found on the substrate surface.

[0021] In some examples, additional processing may be performed to remove carbon contaminants or other contaminants from the surface of the substrate. In some examples, removal of contaminants may be performed before or after the pre-cleaning process. In some examples, removal of contaminants may include plasma processing performed within a plasma cleaning chamber. The plasma processing can use a plasma formed from a gas including hydrogen (H2), helium (He), ammonia (NH3), a fluorine-containing gas, or combinations thereof. The plasma can be inductively coupled or capacitively coupled, the plasma can be formed by a microwave source within the processing chamber, or the plasma can be formed by a remote plasma source.

[0022] In some examples, an epitaxial layer can be formed on the surface of the substrate. When pre-cleaned as described above, the surface of the substrate becomes uniform in terms of oxides and contaminants, and thereafter the quality of the layer formed on the surface of the substrate is improved. An exemplary processing chamber that can be used to perform the epitaxial deposition process is a Centura (trademark) Epi chamber available from Applied Materials, Inc. of Santa Clara, California. Chambers from other manufacturers may also be used.

[0023] FIG. 1A is a cross-sectional view of a processing chamber 100 according to a particular embodiment. The processing chamber 100 is configured to perform a pre-cleaning process. In one example, the processing chamber 100 may be a Siconi (trademark) or Selectra (trademark) chamber available from Applied Materials of Santa Clara, California. The processing chamber 100 generally includes a chamber body 102, a lid assembly 104, and a substrate support assembly 106. The lid assembly 104 is disposed at the upper end of the chamber body 102, and the substrate support assembly 106 is disposed at least partially within the chamber body 102. A vacuum system is used to remove gas from the processing chamber 100. The vacuum system includes a vacuum pump 108 coupled to a vacuum port 110 disposed within the chamber body 102. A pumping ring 122 is disposed within the chamber body 102. The pumping ring 122 provides fluid communication between the interior of the processing chamber 100 and the vacuum port 110 and has a plurality of exhaust ports 126 through which gas is exhausted.

[0024] The lid assembly 104 includes a plurality of stacked components configured to provide gas to a processing region 112 within the chamber 100. The lid assembly 104 is connected to a first gas source 114 and a second gas source 116. Gas from the first gas source 114 is introduced into the lid assembly 104 through an upper port 118. Gas from the second gas source 116 is introduced into the lid assembly 104 through a side port 120. In some examples, the first gas source 114 can provide at least a first portion of a processing gas (e.g., a reactive gas). In some examples, the second gas source 116 can provide a second portion of the processing gas (e.g., a vapor). In some examples, one or more purge gases or carrier gases may be delivered to the processing region 112 from the first gas source 114, the second gas source 116, or another gas source.

[0025] The lid assembly 104 generally includes a showerhead 124 disposed above the processing region 112, through which gas from the first gas source 114 is introduced into the processing region 112. The showerhead 124 may include one or more additional plates (e.g., a shielding plate, a faceplate) disposed on the plate shown in FIG. 1A. Each plate of the showerhead 124 may include a plurality of openings formed therethrough, which connect the gas regions above and below each plate. In some examples, the showerhead 124 may be heated. In some examples, gas may be mixed within or on the showerhead 124 during heating. In one example, the showerhead 124 can be heated to about 190° C. while the substrate being processed is about 10° C.

[0026] In the example shown in FIG. 1A, the showerhead 124 is a dual-channel showerhead having a first channel set 128 and a second channel set 130. The first channel set 128 provides fluid communication above and below the plane of the showerhead 124 such that gas enters the processing region 112 from the upper port 118. The second channel set 130 provides fluid communication with the side port 120 such that gas from the second gas source 116 enters the processing region 112. The dual-channel showerhead can be particularly advantageous for improving the mixing of different gases coming from the first gas source 114 and the second gas source 116.

[0027] The substrate support assembly 106 (also referred to as a “pedestal”) includes a support body 132 (also referred to as a “pack”) that supports the substrate 101 during processing and a stem 136 coupled to the support body 132. The substrate support assembly 106 includes a two-part coating that will be described in more detail below with respect to FIGS. 1C and 1D. In some examples, the support body 132 may be modular and thus can be easily exchanged with another coated component. Thus, if only the coating on the support body 132 is damaged, replacement of the entire substrate support assembly 106 can be avoided.

[0028] The support body main body 132 has a flat or substantially flat substrate support surface 133 (also referred to as the "substrate support region" or "substrate contact surface" of the support body main body 132). Referring to FIG. 1B, the substrate support surface 133 is an area that is under and / or in contact with the substrate 101 (shown by a virtual line in FIG. 1B). In some examples, the substrate support surface 133 may extend a radial distance R1 from the center C1 of the support body main body 132. As shown in FIG. 1B, the outer perimeter of the substrate 101 matches the size of the substrate support surface 133, but in some examples, the substrate 101 may extend beyond the substrate support surface 133. The substrate support surface 133 includes a plurality of surface features (such as the channels 135, ports 137, and recesses 139 shown in FIG. 1B) formed therein, and due to the small size and / or complex structure of the plurality of surface features, it may be difficult to coat them using a conventional single-part coating. Advantageously, the two-part coating described herein covers substantially the entire outer surface of each surface feature, and thus protects against corrosion even with the smallest feature sizes. In some examples, the two-part coating may be able to fill feature sizes with a critical dimension of about 30 μm or less. Advantageously, the two-part coating described herein can fill high aspect ratio features having an aspect ratio of about 5:1 or greater, such as about 10:1 or greater, such as about 20:1 or greater, thereby improving the protection of high aspect ratio features against corrosion.

[0029] As shown in FIG. 1A, the support body main body 132 includes two independent temperature control zones (referred to as "dual zones") for controlling the substrate temperature for uniformity and adjustment of processing from the center to the edge. In the example shown in FIG. 1A, the support body main body 132 has an inner zone 132i and an outer zone 132o surrounding the inner zone 132i. As shown in FIG. 1B, the inner zone 132i and the outer zone 132o are radially separated from each other by a circumferential recess 139. In some other examples, the support body main body 132 may have three or more independent temperature control zones (referred to as "multi-zones").

[0030] The support body main body 132 is coupled to the actuator 134 by a stem 136 that extends through a centrally located opening formed in the bottom of the chamber main body 102. The actuator 134 is flexibly sealed to the chamber main body 102 by a bellows 138 that prevents vacuum leakage around the stem 136. The actuator 134 enables the support body main body 132 to move vertically within the chamber main body 102 between a processing position and a loading position. The loading position is slightly below a substrate opening 140 formed in the side wall of the chamber main body 102.

[0031] The processing chamber 100 also includes a cryogenic kit 142 for lowering the temperature of the substrate to be processed, thereby improving the selectivity of oxide removal (e.g., native oxide removal) compared to other materials, such as low-k dielectric materials and silicon nitride (e.g., SiN). In some examples, the temperature of the substrate to be processed and / or the temperature of the support body main body 132 may be lowered from about -30 °C to about 10 °C. The cryogenic kit 142 provides a continuous flow of cryogenic coolant to the support body main body 132 to cool the support body main body 132 to a desired temperature. In some examples, the cryogenic coolant may include a perfluorinated inert polyether fluid (e.g., Galden® fluid). In the example shown in FIG. 1A, the cryogenic coolant is provided to the inner zone 132i and the outer zone 132o of the support body main body 132 via an inner coolant channel 144i and an outer coolant channel 144o, respectively. The coolant channels are schematically depicted in FIG. 1A and may have an arrangement different from that shown. For example, each coolant channel may be in the form of a loop.

[0032] A system controller 150, such as a programmable computer, is coupled to the processing chamber 100 to control the processing chamber 100 or its components. For example, the system controller 150 can control the operation of the processing chamber 100 using direct control of the substrate support assembly 106, the vacuum pump 108, the first gas source 114, the second gas source 116, the actuator 134, and / or the cryogenic kit 142, or using indirect control of other controllers associated with these. During operation, the system controller 150 enables data collection and feedback from each component to coordinate processing within the processing chamber 100.

[0033] The system controller 150 includes a programmable central processing unit (CPU) 152 operable with a memory 154 (e.g., non-volatile memory) and support circuitry 156. The support circuitry 156 is coupled to the CPU 152 in a conventional manner and includes a cache, a clock circuit, an input / output subsystem, a power supply, etc., and combinations of these coupled to various components of the processing chamber 100.

[0034] In some embodiments, the CPU 152 is one of any form of general-purpose computer processor used in industrial environments, such as a programmable logic controller (PLC), for controlling various monitoring system components and sub-processors. The memory 154 coupled to the CPU 152 is non-transitory and is typically one or more of readily available memories such as random access memory (RAM), read only memory (ROM), floppy disk drive, hard disk, or any other form of digital storage, local or remote.

[0035] In this specification, the memory 154 is in the form of a computer-readable storage medium (e.g., non-volatile memory) that contains instructions which, when executed by the CPU 152, facilitate the operation of the processing chamber 100. The instructions in the memory 154 are in the form of a program product such as a program (e.g., middleware application, device software application, etc.) that implements the method of the present disclosure. The program code may conform to any of various programming languages. In one example, the present disclosure may be implemented as a program product stored in a computer-readable storage medium for use in a computer system. The program of the program product defines the functions of the embodiments (including the methods described herein).

[0036] Examples of computer-readable storage media include, but are not limited to, (i) non-writable storage media where information is permanently stored (e.g., a CD-ROM disk readable by a CD-ROM drive, flash memory, ROM chip, or any type of solid-state non-volatile semiconductor memory, such as a read-only memory device in a computer), and (ii) writable storage media where changeable information is stored (e.g., a floppy disk in a disk drive, or a hard disk drive, or any type of solid-state random access semiconductor memory). Such a computer-readable storage medium is an embodiment of the present disclosure when it carries computer-readable instructions that direct the functions of the methods described herein.

[0037] Figure 1C is an enlarged cross-sectional view of a portion of the stem 136 of FIG. 1A according to a particular embodiment and shows an exemplary surface coating disposed on the stem 136. The stem 136 includes a base layer 160 having an outer surface 162. The "outer surface" can refer to the surface that is exposed before the surface coating is disposed thereon. The stem 136 includes a first coating layer 164 disposed on the outer surface 162. The first coating layer 164 has an outer surface 166. As shown, the first coating layer 164 is in direct contact with the outer surface 162. However, in some other examples, one or more additional layers may be disposed between the base layer 160 and the first coating layer 164. Only a portion of the stem 136 is shown in FIG. 1C, but in some examples, the first coating layer 164 may be disposed over the entire substrate support assembly 106 including the corresponding outer surfaces of the stem 136 and the support body 132. In some examples, the first coating layer 164 may be disposed over the entire support body 132 or over one or more individual surfaces or portions of the support body 132. For example, the first coating layer 164 may be disposed on one or more surfaces of the support body 132 (shown in FIG. 1B) such as on the substrate support surface 133, on a region of the support body 132 outside the substrate support surface 133 (e.g., on the upwardly facing surface 141 surrounding the substrate support surface 133 or around the side surface 143 of the support body 132), or a combination thereof. In some examples, the first coating layer 164 may be disposed across the entire upper surface of the support body 132 including the substrate support surface 133 and the upwardly facing surface 141. The first coating layer 164 may extend a second radial distance R2 from the center C1 of the support body 132. The second radial distance R2 is greater than the first radial distance R1 of the substrate support surface 133.

[0038] In some examples, the base layer 160 may include a metal such as aluminum, a nickel alloy (e.g., Ni100 or Ni200), or other metal alloy, a ceramic such as aluminum nitride or aluminum oxide, a mild steel alloy, a stainless steel alloy, or a combination thereof. In some examples, the first coating layer 164 may include a metal-containing material or alloy. In one example, the first coating layer 164 includes an alloy of nickel and phosphorus formed by electroless nickel plating (ENP). In some examples, the ENP coating may be either a high-phosphate ENP or a low-phosphate ENP. In some other examples, the first coating layer 164 may include electrolytic nickel plating. In some other examples, the first coating layer 164 may be deposited using atomic layer deposition (ALD). In some examples, the first coating layer 164 may include bulk nickel, a noble metal (e.g., platinum or gold), aluminum oxide (e.g., Al2O3), yttrium oxide (e.g., Y2O3), nickel fluoride (e.g., NiF2), magnesium fluoride (e.g., MgF2), or a combination thereof. In some examples, the first coating layer 164 may be a conformal layer that substantially conforms to the contour of the base layer 160. The term "conformal" may refer to a coating having a thickness within + / - 5% of the nominal coating thickness. In some examples, the first coating layer 164 may have a substantially equal thickness across the entire outer surface 162. In some examples, during application, the first coating layer 164 may have fluidity parameters that allow the coating to fill even the smallest features formed on the outer surface 162. For example, the first coating layer 164 may be able to fill feature sizes having critical dimensions in the range of about 30 μm to about 50 μm.

[0039] In some examples, the thickness of the first coating layer 164 may be in the range of about 0.1 μm to about 50 μm. In some examples, the average surface roughness (Ra) of the first coating layer 164 may be in the range of about 2 microinches (μin) to about 64 μin, such as about 20 μin. In some examples, the first coating layer 164 may have resistance to pitting corrosion and discoloration even when exposed to 50 mole% liquid hydrochloric acid (HCl) for at least 24 hours. In some examples, the first coating layer 164 may have resistance to HCl vapor for at least 22 days without pitting corrosion or discoloration.

[0040] FIG. 1D is an enlarged cross-sectional view of a portion of the support body 132 of FIG. 1B showing an exemplary surface coating disposed thereon, according to a particular embodiment. The support body 132 includes a base layer 170 having an outer surface 172. The support body 132 has a first coating layer 174 disposed on the outer surface 172. The first coating layer 174 has an outer surface 176. As shown, the first coating layer 174 is in direct contact with the outer surface 172. However, in some other examples, one or more additional layers may be disposed between the base layer 170 and the first coating layer 174. In some examples, the base layer 170 may include a metal such as aluminum, stainless steel, nickel alloy, or other metal alloy, a ceramic such as aluminum nitride or aluminum oxide, or a combination thereof. In some examples, the base layer 170 may be formed from the same material as the base layer 160. In some examples, the first coating layer 174 may include one or more aspects of the first coating layer 164 described above. In some examples, the first coating layer 174 may be the same as the first coating layer 164 of FIG. 1C. Although not shown in FIG. 1D, the first coating layer 174 may cover substantially the entire outer surface 172 of each surface feature (such as the channels 135, ports 137, recesses 139, etc. shown in FIG. 1B) formed in the substrate support region of the base layer 170.

[0041] The support body main body 132 includes a second coating layer 178 disposed on the outer surface 176 of the first coating layer 174. The second coating layer 178 has an outer surface 180. As shown in the figure, the second coating layer 178 is in direct contact with the outer surface 176. However, in some other examples, one or more additional layers may be disposed between the first coating layer 174 and the second coating layer 178.

[0042] In some examples, the second coating layer 178 may include a material that does not contain metal contaminants (also referred to as "non-metallic" or "metal-free"). In some examples, the non-metallic material may include a material having a metal concentration of about 2000 ppm or less. In some examples, the second coating layer 178 may be deposited using chemical vapor deposition (CVD), plasma enhanced CVD (PECVD), ALD, or plasma enhanced ALD (PEALD). In some examples, the second coating layer 178 may be an amorphous film.

[0043] In some examples, the second coating layer 178 may be silicon carbide (e.g., SiC) or may include silicon carbide. In some other examples, the second coating layer 178 may be silicon or may include silicon. Generally, a silicon coating is softer than silicon carbide and has equal or better etching resistance. For example, the hardness of a silicon coating can be in the range of about 4,000 N / mm 2 (MPa) to about 6,000 N / mm 2 (MPa), in contrast to a silicon carbide coating that can have a hardness in the range of about 10,000 N / mm 2 (MPa) to about 16,000 N / mm 2 (MPa). Thus, silicon may be less likely to damage the backside surface of a semiconductor substrate, which can be particularly advantageous for coating surfaces that contact a semiconductor substrate, such as the substrate support surface 133 (shown in FIG. 1B).

[0044] In some other examples, the second coating layer 178 may be, or may include, a fully fluorinated film. In some examples, the fully fluorinated film may be a self-assembled monolayer (SAM). In contrast to other coatings such as silicon carbide, the fully fluorinated SAM has the advantages of less porosity, lower water absorption, and / or less gas evolution. In some examples, the thickness of the fully fluorinated film may be from about 5 nm to about 20 nm, such as from about 5 nm to about 10 nm, from about 10 nm to about 15 nm, or from about 15 nm to about 20 nm. In some examples, the fully fluorinated film may completely cover the underlying surface. In some examples, the perfluoride precursor of the fully fluorinated film may be, or may include, a tetrafluoroethylene-based precursor (e.g., CF3-(CF2)9-(CH2)2-SiCl3) that covalently bonds to the underlying surface. When the tetrafluoroethylene-based precursor is CF3-(CF2)9-(CH2)2-SiCl3, the covalently bonded chemical structure may be CF3-(CF2)9-(CH2)2-Si-O-. Other suitable perfluoride precursors may include, among others, perfluorooctane or tridecafluoro-1,1,2,2-tetrahydrooctyltrichlorosilane (FOTS), or may include these. Generally, the above fully fluorinated film contains short-chain molecules of polytetrafluoroethylene (PTFE). Thus, the fully fluorinated film is characterized by low friction and / or low surface energy, which can be particularly advantageous for coating surfaces that contact semiconductor substrates such as the substrate support surface 133 (shown in FIG. 1B). The above-described fully fluorinated film may be deposited using techniques such as ALD.

[0045] In some other examples, the second coating layer 178 may be or may include yttrium oxyfluoride (YOF). In some examples, the thickness of the YOF coating may be from about 100 nm to about 500 nm, such as from about 100 nm to about 200 nm, from about 200 nm to about 300 nm, from about 300 nm to about 400 nm, or from about 400 nm to about 500 nm. In some examples, the YOF coating may completely cover the surface beneath it. In some examples, the individual concentrations of yttrium atoms, oxygen atoms, and fluoride atoms in the YOF coating may be in the range of about 25 atomic (at.) % to about 40 at. %. In one example, the concentration of each component may be approximately equal (i.e., about 33 at. % Y, 33 at. % O, and 33 at. % F). Generally, the above YOF coating is more resistant to etching (e.g., when exposed to AHF / water treatment chemicals) compared to other coatings such as silicon carbide. In some examples using 4 wt% to 25 wt% HF in liquid water, the etching rate of the YOF coating may be less than about 0.5 angstroms per minute (Å / min). In some other examples, in an application-specific processing environment (e.g., using the above-described processing chamber 100 that uses HF and water vapor at a temperature below about 0 °C), the etching rate of the YOF coating may be less than about 0.15 Å / min. The YOF coating described above can be deposited using ALD, among other techniques.

[0046] In some examples, the second coating layer 178 has a high bulk density corresponding to a low void volume. In some examples, the second coating layer 178 may have a bulk density of about 90% or more, such as about 95% or more, such as about 99% or more, such as about 100%, as a ratio of the volume mass density of the coating material. In some examples, the thickness of the second coating layer 178 may be in the range of about 100 nm to about 40 μm, such as about 100 nm to about 40 μm, such as about 1 μm to about 10 μm, such as about 10 μm to about 20 μm, such as about 20 μm to about 30 μm, such as about 30 μm to about 40 μm, such as about 30 μm. In some examples, the second coating layer 178 may have higher durability by using a thicker coating (e.g., greater than about 1 μm) compared to using a thinner coating (e.g., less than about 1 μm). Thus, in at least some embodiments, CVD can be a particularly advantageous process compared to ALD for forming the second coating layer 178. In some examples, the average surface roughness (Ra) of the second coating layer 178 may be in the range of about 5 μin to about 20 μin. In some examples, the electrical resistivity of the second coating layer 178 is about 10 7 ohm·centimeter to about 10 8 ohm·centimeter.

[0047] Advantageously, as shown in FIG. 1D, when the substrate support surface 133 of the support body 132 includes a non-metallic coating, metal contamination on the back surface of the substrate is reduced or prevented as compared to conventional surface materials containing metal elements such as aluminum oxide (e.g., Al2O3). The portion of the support body 132 shown in FIG. 1D corresponds to the substrate support surface 133. In some examples, the second coating layer 178 may be disposed only on the substrate support surface 133. In other words, the second coating layer 178 may extend at a radial distance approximately equal to a first radial distance R1 from the center C1 of the support body 132. Thus, the second coating layer 178 may extend at a radial distance shorter than a second radial distance R2 of the first coating layer 164 from the center C1. In some other examples, the second coating layer 178 may be applied to an area outside the substrate support surface 133. For example, the second coating layer 178 may be applied to the entire upper surface of the support body 132 including the upward surface 141 (shown in FIG. 1B) surrounding the substrate support surface 133. In some examples, the side surface 143 (e.g., the vertical side surface) of the support body 132 does not have the second coating layer 178. In some other examples, the second coating layer 178 may be applied around the side surface 143 (shown in FIG. 1B) of the support body 132. However, the portion of the second coating layer 178 disposed on a vertical surface such as the side surface 143 of the support body 132 may reduce the overall coating quality. Thus, it may be advantageous to avoid coating the side surface 143. In some examples, the second coating layer 178 may be disposed over the entire support body 132. In some examples, the stem 136 may not have the second coating layer 178. Applying the second coating layer 178 to the stem 136 may be particularly difficult in some cases. Thus, it may be advantageous to avoid coating the stem 136.

[0048] In some examples, the coated substrate support assembly 106 (e.g., shown in FIGS. 1C-1D) may have an increased thermal conductivity compared to a corresponding uncoated support. The coating embodiments disclosed herein are particularly advantageous for improving the thermal properties of a support formed at least in part from aluminum because an uncoated aluminum-based support has limited control over substrate temperature compared to a more thermally conductive material.

[0049] FIG. 2 is a diagram illustrating a method 200 of forming an exemplary surface coating of FIG. 1C according to a particular embodiment. In operation 202, any first surface treatment is applied to the outer surface 162 of the base layer 160. In some examples, the first surface treatment may include a cleaning process that removes oxides and trace metals at a uniform density. In some examples, the first surface treatment may include O2 plasma cleaning. In some examples, the cleaning process may include the above-described pre-cleaning process that may be performed within the processing chamber shown in FIG. 1A. In some other examples, the cleaning process may use milder processing chemicals compared to the pre-cleaning process, in which case the milder processing conditions may be more suitable for cleaning the unfinished surface of the substrate support assembly (e.g., an uncoated surface or a surface coated with only a single coating layer).

[0050] In operation 204, a first material precursor is deposited on the base layer 160 to form a first coating layer 164. In some examples, the first material precursor may be deposited using ENP or electroless nickel plating, among other processes suitable for depositing the material that forms the first coating layer 164 as described above. In some examples, the portion of the substrate support assembly 106 to be coated (e.g., the support body 132 and / or the stem 136) is immersed in a bath containing the first material precursor.

[0051] In operation 206, an optional second surface treatment is applied to the outer surface 166 of the first coating layer 164. In some examples, the second surface treatment may include one or more of the cleaning processes described above with respect to operation 202.

[0052] FIG. 3 is a diagram showing a method 300 for forming an exemplary surface coating of FIG. 1D according to a particular embodiment. In operation 302, an optional first surface treatment is applied to the outer surface 172 of the base layer 170. In some examples, the first surface treatment may include one or more of the cleaning processes described above with respect to operation 202.

[0053] In operation 304, a first material precursor is deposited on the base layer 170 to form a first coating layer 174. In some examples, the first material precursor may be deposited using ENP or electroless nickel plating, among other processes suitable for depositing the material for forming the first coating layer 164 as described above.

[0054] In operation 306, an optional second surface treatment is applied to the outer surface 176 of the first coating layer 174. In some examples, the second surface treatment may include one or more of the cleaning processes described above with respect to operation 202. In some examples, the second surface treatment may include reactive ion etching. In some examples, the second surface treatment may include reversed arc plasma cleaning.

[0055] In operation 308, a second material precursor is deposited on the first coating layer 174 to form a second coating layer 178. In some examples, the second material precursor may be deposited using CVD, PECVD, ALD, or PEALD.

[0056] In operation 310, an optional third surface treatment is applied to the outer surface 180 of the second coating layer 178. In some examples, the third surface treatment may include one or more of the cleaning processes described above with respect to operation 202.

[0057] Figure 4 is an enlarged cross-sectional view of a portion of a support body configured for use within the processing chamber 100 of FIG. 1A, showing another exemplary surface coating disposed thereon. The surface coating shown in FIG. 4 is similar to the surface coating shown in FIG. 1D, except that the first coating layer 174 is omitted. In such an example, if the support body is formed from a material resistant to the processing environment, the first coating layer 174 is not necessary. Instead, the second coating layer 178 is in direct contact with the outer surface 172 of the base layer 170. In some other examples, one or more additional layers can be disposed between the base layer 170 and the second coating layer 178. In one example, the base layer 170 may be a nickel alloy (e.g., Ni100 or Ni200), or may include a nickel alloy, and the second coating layer 178 may be silicon carbide (e.g., SiC), silicon, a perfluorinated film, YOF, or a combination thereof, or may include them.

[0058] The portion of the support body shown in FIG. 4 corresponds to the substrate support surface 133. However, in some examples, as described above with respect to FIG. 1D, the second coating layer 178 may be applied directly to the base layer 170 in an area outside the substrate support surface 133.

[0059] Advantages of the present disclosure include an improved coating for a substrate support assembly of a processing chamber. Certain embodiments provide a two-part surface coating as opposed to a conventional one-part coating. The two-part coating includes a first coating that reduces corrosion of the entire surface of the substrate support assembly and a second coating that is free of metal contaminants that reduce metal contamination on the back side of the substrate.

[0060] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof.

Claims

1. A system comprising a processing chamber and a support pedestal configured to support a substrate within the processing chamber, wherein the support pedestal includes a body having an upper surface, the upper surface of the body being provided with a two-part coating, the two-part coating including: a first coating layer extending at a first radial distance from the center of the body, the first coating layer including at least one of a metal-containing material or an alloy; a second coating layer disposed on the first coating layer; wherein the second coating layer extends at a second radial distance from the center of the body, the first radial distance being greater than the second radial distance; and the second coating layer is non-metallic; a stem coupled to the body and extending through an opening in the bottom of the processing chamber, the stem having an outer stem surface, the first coating layer being disposed on the outer stem surface.

2. The system according to claim 1, wherein the first coating layer is disposed over the entire upper surface of the body.

3. The system according to claim 1, wherein the first coating layer is disposed over the entire body and the second coating layer is not present on the vertical side surfaces of the body.

4. The system according to claim 1, wherein the first coating layer is disposed on the substrate contact surface of the body and on the region of the body outside the substrate contact surface, and the second coating layer is disposed only on the substrate contact surface of the body.

5. The first coating layer includes electroless nickel plating, and the second coating layer includes either a fully fluorinated substituted film including a self-assembled monolayer or yttrium oxyfluoride.

6. The system according to claim 5, wherein the thickness of the first coating layer is in the range of 0.1 μm to 50 μm.

7. The second coating layer has a bulk density of 90% or more as a ratio of the volume mass density of the coating material.

8. The thickness of the fully fluorinated substituted film is 5 nm to 20 nm. ​ ​ ​ ​

9. The system according to claim 5, wherein the thickness of the yttrium oxyfluoride coating is from 100 nm to 500 nm.

10. The system according to claim 5, wherein the individual concentrations of yttrium atoms, oxygen atoms, and fluoride atoms in the yttrium oxyfluoride coating are in the range of 25 atomic % to 40 atomic %.

11. The processing chamber is configured to clean the substrate, The processing chamber, comprises a chamber body, and a lid assembly disposed at an upper end of the chamber body, and the lid assembly is a dual-channel showerhead having a first channel set that provides fluid communication above and below a plane of the showerhead, the dual-channel showerhead, and a second channel set that provides fluid communication with a side port of the chamber body and the first coating layer is disposed over the entire upper surface of the body, The system according to claim 1, wherein the upper surface extends at a first radial distance from the center of the body.

12. The system according to claim 11, wherein the first coating layer is further disposed on a vertical side surface of the body, and the second coating layer is not present on the vertical side surface and the stem of the body.

13. The system according to claim 11, further comprising an epitaxial chamber for growing an epitaxial layer on the substrate after the substrate has been cleaned by the processing chamber.

14. The system according to claim 11, wherein the second coating layer is disposed only on a substrate contact surface of the body.

15. A method of forming a surface coating on a support pedestal of a processing chamber, comprising: depositing a first material over an entire upper surface of a body of the support pedestal and over an outer stem surface of a stem of the support pedestal, thereby forming a first coating layer, the first material including electroless nickel plating, the stem being coupled to the body and extending through an opening at a bottom of the processing chamber, depositing the first material; Depositing a second material on only a part of the upper surface of the body, thereby forming a second coating layer, wherein the second material is non-metallic. A method comprising. **Claim 16**: The first coating layer includes electroless nickel plating. The method according to claim 15, wherein the second coating layer includes either a fully fluorinated substituted film including a self-assembled monolayer or yttrium oxyfluoride. **Claim 17** The method according to claim 15, wherein the upper surface extends at a first radial distance from the center of the body, and the second coating layer extends at a second radial distance smaller than the first radial distance from the center of the body. **Claim 18** The method according to claim 15, further comprising depositing the first material over the entire body.

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