Substrate support assembly having deposited surface features

Abstract

A method of manufacturing an electrostatic chuck includes polishing a surface of a ceramic body of an electrostatic chuck to produce a polished surface and depositing a ceramic coating onto the polished surface of the ceramic body to produce a coated ceramic body. The method further includes disposing a mask over the coated ceramic body, the mask including a plurality of oblong apertures, and depositing a ceramic material through the plurality of oblong apertures of the mask to form a plurality of oblong mesas on the coated ceramic body, wherein the plurality of oblong mesas have rounded edges. The mask is then removed from the coated ceramic body, and the plurality of oblong mesas are polished.

Description

[0001] This application is a divisional application of patent application number 201680067355.X, filed on June 1, 2016, entitled "Substrate Support Assembly with Deposited Surface Feature Structure". Technical Field

[0002] Embodiments of the present invention generally relate to substrate support assemblies having a plasma-resistant protective layer with deposited surface feature structures, such as electrostatic chucks. Background Technology

[0003] In the semiconductor industry, devices are manufactured using several processes that produce structures with ever-shrinking dimensions. Some processes, such as plasma etching and plasma cleaning, expose substrate supports, such as electrostatic chucks (ESCs) (e.g., exposing the edges of the ESC during wafer processing and the entire ESC during chamber cleaning) to a high-speed plasma stream to etch or clean the substrate. The plasma can be highly corrosive and may corrode the processing chamber and other surfaces exposed to the plasma.

[0004] ESCs typically have surface feature structures formed by placing a positive mask on the surface of the ESC and then bead blasting the exposed portions of the ESC. The positive mask is a mask containing an exact copy of the pattern to be retained on the wafer. The bead blasting process results in sharp edges and cracks in the ESC surface. Furthermore, the spaces between the formed surface feature structures (called valleys) have high roughness, which provides pits that trap particles and spikes that break off during thermal expansion. Trapped particles and broken spikes cause particle contamination on the back side of the retained wafer during processing. Summary of the Invention

[0005] In one embodiment, an electrostatic chuck includes a thermally conductive base and a ceramic body bonded to the thermally conductive base, the ceramic body having embedded electrodes. A protective ceramic coating covers the surface of the ceramic body. A plurality of deposited elliptical mesas are distributed on the surface of the ceramic body. Each of these elliptical mesas has a rounded edge.

[0006] In one embodiment, a method of manufacturing an electrostatic chuck includes polishing the surface of a ceramic body of the electrostatic chuck to produce a polished surface. The method further includes depositing a protective ceramic coating onto the polished surface of the ceramic body to produce a coated ceramic body. The method further includes providing a mask over the coated ceramic body, the mask including a plurality of elliptical apertures (e.g., circular apertures). The method further includes depositing ceramic material through the plurality of elliptical apertures of the mask to form a plurality of elliptical mesa on the coated ceramic body, wherein the plurality of elliptical mesa (e.g., circular mesa) has rounded edges. The mask is then removed, and the plurality of elliptical mesa are polished.

[0007] In one embodiment, a circular mask for depositing elliptical mesa onto the surface of an electrostatic chuck includes a body having a first diameter smaller than a second diameter of the electrostatic chuck, the mask being placed on the electrostatic chuck. The circular mask further includes a plurality of elliptical through-holes in the body having a depth-to-width ratio of approximately 1:2 to approximately 2:1. At least one elliptical hole has a flared apex and a flared base, wherein the flared apex is used to inject particles into the electrostatic chuck through the elliptical hole to form elliptical mesa on the electrostatic chuck, and wherein the flared base prevents the elliptical mesa from contacting the mask. Attached Figure Description

[0008] The present invention is illustrated by way of example, rather than by way of limitation, in the accompanying drawings, in which similar element symbols indicate similar elements. It should be noted that different references to "a" or "an" embodiment in this disclosure do not necessarily refer to the same embodiment, and such references mean at least one.

[0009] Figure 1 A cross-sectional side view of one embodiment of the processing chamber is shown;

[0010] Figure 2A A top view illustrating an example pattern of an elliptical platform on the surface of an electrostatic chuck;

[0011] Figure 2B Draw Figure 2A Vertical cross-sectional view of the electrostatic chuck;

[0012] Figure 3A -D shows an illustrative side profile of a tabletop according to an embodiment of the present invention;

[0013] Figure 4 A cross-sectional side view of one embodiment of the electrostatic chuck is shown;

[0014] Figure 5 The illustration shows one embodiment of a process for manufacturing an electrostatic chuck;

[0015] Figure 6A -C illustrates the deposition of ceramic material onto the surface of an electrostatic chuck using a mask to form a circular mesa with rounded edges; and

[0016] Figure 7 The illustration is a top view of a mask used to form a mesa and a ring on a ceramic body of an electrostatic chuck according to one embodiment. Detailed Implementation

[0017] Embodiments of the present invention provide a substrate support assembly (e.g., an electrostatic chuck) having a deposition mesa with rounded edges. Embodiments also provide a substrate support assembly having a protective ceramic coating formed on a ceramic body of the substrate support assembly. The protective ceramic coating provides resistance to plasma corrosion to protect the ceramic body. The mesa can be deposited on the protective ceramic coating and is also resistant to plasma corrosion.

[0018] In one embodiment, the electrostatic chuck includes a thermally conductive base (e.g., a metal or metal alloy base) and a ceramic body (e.g., an electrostatic puck) bonded to the thermally conductive base. A protective ceramic coating, acting as a protective layer, covers the surface of the ceramic body, and a plurality of elliptical (e.g., circular) mesa are disposed on the protective ceramic coating. In one embodiment, the electrostatic chuck is manufactured by first depositing the protective ceramic coating onto the ceramic body, and then depositing the elliptical mesa onto the ceramic body through holes in a mask. As used herein, the term mesa refers to a protrusion on a substrate having a steep edge and a flat or gently sloping top surface.

[0019] In particular, the electrostatic chucks and other substrate supports described in the embodiments herein have mesa surfaces created by depositing mesa surfaces using a negative mask. A negative mask is a mask containing a pattern that is exactly the opposite of the pattern to be formed on the electrostatic chuck. In other words, the negative mask has gaps where the feature structures will be formed on the electrostatic chuck. In contrast, conventionally, mesa surfaces are formed on the surface of the electrostatic chuck by sandblasting the surface of the electrostatic chuck using a positive mask (a mask containing an exact copy of the pattern to be transferred to the electrostatic chuck). Mesa surfaces formed by sandblasting have sharp edges that can fracture and cause particulate contamination on the back side of the wafer supported by the electrostatic chuck. However, the mesa surfaces deposited according to the embodiments described herein have more fracture-resistant rounded edges (e.g., a top-hat profile).

[0020] Furthermore, the sandblasting process traditionally used to create mesa in electrostatic chucks results in high surface roughness in the regions (valleys) between the generated mesa. This high surface roughness acts as pits that trap particles, which may then be released onto the back side of the supporting wafer during processing. Additionally, localized spikes in the rough surfaces of the valleys can break off and detach during thermal cycling, becoming another source of particulate contamination. However, in the embodiments described herein, the surface of the electrostatic disk is polished prior to mesa deposition. Therefore, the valleys between the deposited mesa have very low surface roughness (e.g., approximately 4–10 microinches), further reducing particulate contamination on the back side.

[0021] The electrostatic chuck described in the embodiments herein also includes a blanket protective ceramic coating, which acts as a protective layer for the electrostatic chuck. The protective ceramic coating covers the surface of the electrostatic chuck and is deposited onto the electrostatic chuck after the surface of the electrostatic chuck has been polished. The protective ceramic coating is highly conformal and has a surface roughness substantially the same as that of the polished electrostatic chuck. Both the protective ceramic coating and the platform deposited on the protective ceramic coating can be plasma-resistant materials, such as yttrium aluminum garnet (YAG). Therefore, the electrostatic chuck (including the platform formed on the electrostatic chuck) can be resistant to chlorine, fluorine, and hydrogen-based plasmas.

[0022] Figure 1 This is a cross-sectional view of one embodiment of a semiconductor processing chamber 100 in which a substrate support assembly 148 is disposed. According to the embodiment described herein, the substrate support assembly 148 includes an electrostatic chuck 150 having an electrostatic disk 166 having a rounded platform for placement.

[0023] The processing chamber 100 includes a chamber body 102 and a cover 104 surrounding an internal volume 106. The chamber body 102 may be made of aluminum, stainless steel, or other suitable materials. The chamber body 102 typically includes sidewalls 108 and a bottom 110. An outer liner 116 may be disposed adjacent to the sidewalls 108 to protect the chamber body 102. The outer liner 116 may be made of and / or coated with a plasma- or halogen-containing gas-resistant material. In one embodiment, the outer liner 116 is made of alumina. In another embodiment, the outer liner 116 is made of and / or coated with yttrium oxide, yttrium alloys, or oxides thereof.

[0024] The exhaust port 126 can be defined within the chamber body 102, and the internal volume 106 can be coupled to the pump system 128. The pump system 128 may include one or more pumps and throttle valves for extracting and regulating the pressure of the internal volume 106 of the processing chamber 100.

[0025] A cover 104 may be supported on the sidewall 108 of the chamber body 102. The cover 104 can be opened to allow access to the internal volume 106 of the processing chamber 100 and can provide a seal to the processing chamber 100 when closed. A gas panel 158 may be coupled to the processing chamber 100 to provide processing and / or cleaning gases to the internal volume 106 via a gas distribution assembly 130, which is part of the cover 104. Examples of processing gases that may flow into the processing chamber include halogen-containing gases such as C2F6, SF6, SiCl4, HBr, NF3, CF4, CHF3, CH2F3, Cl2, and SiF4, as well as other gases such as O2 or N2O. Notably, the processing gases may be used to generate highly corrosive chlorine-based plasmas, fluorine-based plasmas, and / or hydrogen-based plasmas. The gas distribution assembly 130 may have a plurality of apertures 132 on its downstream surface to guide gas flow to the surface of a substrate 144 (e.g., a wafer) supported by a substrate support assembly 148. Alternatively, the gas distribution assembly 130 may have a central aperture through which gas is supplied via a ceramic gas nozzle.

[0026] A substrate support assembly 148 is disposed within the internal volume 106 of the processing chamber 100, below the gas distribution assembly 130. During processing, the substrate support assembly 148 holds the substrate 144. An inner liner 118 may be coated around the substrate support assembly 148. The inner liner 118 may be a halogen-resistant gas-containing material, such as those discussed with reference to the outer liner 116. In one embodiment, the inner liner 118 may be made of the same material as the outer liner 116.

[0027] In one embodiment, the substrate support assembly 148 includes a mounting plate 162 supporting a base 152 and an electrostatic chuck 150. The mounting plate 162 is coupled to the bottom 110 of the chamber body 102 and includes channels for routing utilities (e.g., fluid, power lines, sensor leads, etc.) to the thermally conductive base 164 and the electrostatic disk 166. In one embodiment, the electrostatic chuck 150 also includes the thermally conductive base 164 bonded to the electrostatic disk 166 by a silicone bond 138.

[0028] The electrostatic disk 166 may be a ceramic body including one or more clamping electrodes (also referred to as chucking electrodes) 180, which are controlled by a chucking power source 182. In one embodiment, the electrostatic disk 166 is composed of aluminum nitride (AlN) or aluminum oxide (Al2O3). Alternatively, the electrostatic disk 166 may be composed of titanium oxide (TiO), titanium nitride (TiN), silicon carbide (SiC), or the like. The chucking electrodes 180 (or other electrodes located in the electrostatic disk 166) may be further coupled to one or more radio frequency (RF) power sources 184, 186 via a matching circuit 188 to maintain plasma formed from process gases and / or other gases within the processing chamber 100. The one or more RF power sources 184, 186 are typically capable of generating RF signals with frequencies from about 50 kHz to about 3 GHz and power up to about 10,000 watts.

[0029] The upper surface of the electrostatic disk 166 is covered with a protective ceramic coating 136, which is deposited on the electrostatic disk 166. In one embodiment, the protective ceramic coating is Y3Al5O. 12 (Yttrium aluminum garnet, YAG) coating. Alternatively, the protective ceramic coating may be Al2O3, AlN, Y2O3 (yttrium oxide), or AlON (aluminum oxynitride). The upper surface of the electrostatic disk 166 further includes a plurality of mesa and / or other surface features deposited on the upper surface. The mesa and / or other surface features may be deposited on the surface of the electrostatic disk 166 before or after the deposition of the protective ceramic coating 136.

[0030] The electrostatic disk 166 also includes one or more gas channels (e.g., holes drilled in the electrostatic disk 166). In operation, a back-side gas (e.g., He) can be supplied to the gas channels under controlled pressure to enhance heat transfer between the electrostatic disk 166 and the substrate 144.

[0031] The thermally conductive base 164 can be a metal base made of, for example, aluminum or an aluminum alloy. Alternatively, the thermally conductive base 164 can be made of a ceramic composite, such as an aluminum-silicon alloy infiltrated with SiC, to match the coefficient of thermal expansion of the ceramic body. The thermally conductive base 164 should provide good strength and durability as well as heat transfer performance. In one embodiment, the thermally conductive base 164 has a thermal conductivity exceeding 200 watts per meter Kelvin (W / m K).

[0032] The thermally conductive base 164 and / or the electrostatic disk 166 may include one or more embedded heating elements 176, embedded thermal insulators 174, and / or conduits 168, 170 to control the lateral temperature distribution of the substrate support assembly 148. The conduits 168, 170 may be fluidly coupled to a fluid source 172, which circulates a temperature-regulating fluid through the conduits 168, 170. In one embodiment, the embedded thermal insulator 174 may be disposed between the conduits 168, 170. One or more embedded heating elements 176 may be regulated by a heater power supply 178. The temperature of the thermally conductive base 164 may be controlled using the conduits 168, 170 and one or more embedded heating elements 176 to heat and / or cool the electrostatic disk 166 and the substrate 144 being processed. Multiple temperature sensors 190, 192 may be used to monitor the temperature of the electrostatic disk 166 and the thermally conductive base 164, and the temperature sensors 190, 192 may be monitored using a controller 195.

[0033] Figure 2A A top view depicting an exemplary pattern of elliptical mesa 202 on the surface 212 of the electrostatic disk 200. For illustrative purposes, only 16 mesa are shown. However, the surface of the electrostatic disk 200 may have hundreds or thousands of mesa formed thereon. Figure 2B Depicting along Figure 2A A vertical cross-sectional view of the electrostatic disk 200 taken along centerline 3-3. The electrostatic disk 200 includes one or more embedded electrodes 250. The electrostatic disk 200 may be the uppermost component of an electrostatic chuck, such as... Figure 1 An electrostatic chuck 150. An electrostatic disk 200 has an annular periphery and a disk-like shape, which can generally match the shape and size of the supported substrate 244 located on the electrostatic disk 200. In one embodiment, the electrostatic disk 200 corresponds to... Figure 1 166 electrostatic disks.

[0034] exist Figure 2A In the illustrated example, the elliptical mesa 202 is depicted as being positioned along concentric circles 204 and 206 on the surface 212 of the electrostatic disk 200. However, any pattern of elliptical mesa 202 distributed on the surface 212 of the electrostatic disk 200 is possible. In one embodiment, the elliptical mesa 202 is circular. Alternatively, the shape of the elliptical mesa 202 may be elliptical or have other elliptical shapes.

[0035] Elliptical mesa 202 are formed as individual pads with a thickness between 2 micrometers and 200 micrometers (μm) and dimensions (e.g., diameter) in a planar view between 0.5 mm and 5 mm. In one embodiment, the elliptical mesa 202 has a thickness between 2 micrometers and 20 micrometers and a diameter of about 0.5 mm to 3 mm. In one embodiment, the elliptical mesa 202 has a thickness of about 3 micrometers to 16 micrometers and a diameter of about 0.5 mm to 2 mm. In one embodiment, the mesa has a thickness of about 10 micrometers and a diameter of about 1 mm. In another embodiment, the mesa has a thickness of about 10 micrometers to 12 micrometers and a diameter of about 2 mm. In some embodiments, the mesa has a uniform shape and size. Alternatively, the various mesa may have different shapes and / or different sizes. The sidewalls of the elliptical mesa 202 may be vertical or inclined. Notably, each elliptical mesa 202 has a rounded edge, wherein the elliptical mesa 202 will contact the substrate 244 at the rounded edge. This minimizes breakage of the elliptical mesa 202 and reduces particulate contamination on the back side of the substrate 244. Furthermore, the rounded edges reduce or eliminate scratches on the back side of the substrate 244 caused by clamping. Alternatively, the elliptical mesa 202 may have a chamfered edge.

[0036] Some illustrative side profile diagrams of the elliptical platform 202 are shown in... Figures 3A-3D In the middle. As shown in the figure, in Figures 3A-3D In each of the exemplified side profiles, the edge of the tabletop is rounded. Figure 3A -B's side profile is a variation of the top-hat-shaped profile.

[0037] Return to reference Figure 2A-2B The elliptical mesa 202 is a deposition mesa formed by a deposition process, such as ion-assisted deposition (IAD), to create a dense, conformal ceramic layer. (See reference...) Figure 5 The deposition of the elliptical mesa 202 is discussed. In the illustrated embodiment, the elliptical mesa 202 has been deposited directly onto the surface 212 of the electrostatic disk 200 without first depositing a protective ceramic coating on surface 212. However, a protective ceramic coating may also be deposited before or after the deposition of the elliptical mesa 202. The average surface roughness of the elliptical mesa 202 can be approximately 2 microinches to 12 microinches. In one embodiment, the average surface roughness of the elliptical mesa 202 is approximately 4 microinches to 8 microinches.

[0038] In one embodiment, the elliptical mesa 202 is formed of YAG. In another embodiment, the mesa is made of amorphous ceramic comprising yttrium, aluminum, and oxygen (e.g., YAG in amorphous form). The amorphous ceramic may comprise at least 8 wt% yttrium. In one embodiment, the amorphous ceramic comprises about 8-20 wt% yttrium, 20-32 wt% aluminum, and 60-70 wt% oxygen. In another embodiment, the amorphous ceramic comprises about 9-10 wt% yttrium, about 25-26 wt% aluminum, and about 65-66 wt% oxygen. In alternative embodiments, the elliptical mesa 202 may be Al2O2, AlN, Y2O3, or AlON.

[0039] The surface 212 of the electrostatic disk 200 also includes a raised lip in the form of a ring 218 on its outer periphery 220. The thickness and material composition of the ring 218 may be the same as or substantially the same as the thickness and material composition of the elliptical mesa 202. The ring 218 may have been formed by deposition concurrently with the formation of the elliptical mesa 202. The ring 218 may also have a rounded edge that contacts the substrate 244. Alternatively, the ring 218 may have a chamfered edge, or it may have an edge that is neither rounded nor chamfered. In one embodiment, the inner edge of the ring 218 is rounded, while the outer edge of the ring 218 is not rounded.

[0040] The tops of the elliptical mesa 202 and ring 218 contact the back side of the supported substrate 244. The elliptical mesa 202 minimizes the contact area between the back side of the substrate 244 and the surface 212 of the electrostatic disk 200, and facilitates locking and de-chucking operations. Gases such as He can also be pumped into the area between the substrate and the electrostatic chuck 200 to promote heat transfer between the substrate 244 and the electrostatic chuck 200. The ring 218 serves as a sealing ring to prevent gas from escaping from the space between the electrostatic chuck 200 and the substrate 244.

[0041] Figure 4A cross-sectional side view of an electrostatic chuck 400 is illustrated according to one embodiment. The electrostatic chuck 400 includes a thermally conductive base 464 (e.g., a metal base) coupled to an electrostatic disk 402 by an adhesive 452, such as a polysiloxane adhesive. The adhesive 452 may be, for example, a polydimethylsiloxane (PDMS) adhesive. The electrostatic disk 402 may be a generally disk-shaped dielectric ceramic body having one or more embedded electrodes. The electrostatic disk 402 may be a bulk sintered ceramic, such as alumina (Al2O3), aluminum nitride (AlN), titanium oxide (TiO), titanium nitride (TiN), silicon carbide (SiC), and the like. The electrostatic disk 402 may include one or more embedded electrodes 436 and / or resistance heating elements 438 (e.g., internal and external resistance heating elements). A quartz ring 446 or other protective ring may surround and cover certain portions of the electrostatic chuck 400. A substrate 444 may be lowered over the electrostatic chuck 400 and held in place by electrostatic force by providing a signal to one or more electrodes 436.

[0042] The thermally conductive base 464 is configured to provide physical support for the electrostatic disk 402. In some embodiments, the thermally conductive base 464 is also configured to provide temperature control. The thermally conductive base 464 may be made of a thermally conductive material, such as a metal, like aluminum or stainless steel. The thermally conductive base 464 may include one or more heat exchangers, such as embedded heating elements, fluid channels that provide heat exchange by circulating cooling and heating fluids through channels, or combinations thereof. Figure 1 In this embodiment, the thermally conductive base 464 includes multiple fluid channels, also referred to as conduits 470 (e.g., inner and outer conduits), through which fluid can flow to heat or cool the thermally conductive base 464, the electrostatic chuck 400, and the substrate 444 via heat exchange between the thermally conductive base 464, other components of the electrostatic chuck 400, and the substrate 444. A temperature sensor 490 can be used to monitor the temperature of the thermally conductive base 464.

[0043] In one embodiment, the electrostatic chuck 400 further includes a ceramic coating 496 that fills and / or covers defects in the surface of the electrostatic disk 402, such as microcracks, pores, pinholes, and the like. The ceramic coating 496 may be referred to as a cover ceramic coating or a blanket ceramic coating, and may cover the entire surface of the electrostatic disk 402. Alternatively, the electrostatic chuck 400 may not include the ceramic coating 496. In one embodiment, the ceramic coating 496 is made of the same ceramic as the electrostatic disk 402. Therefore, if the electrostatic disk 402 is AlN, then the cover ceramic coating 496 is also AlN. Or, if the electrostatic disk 402 is Al2O3, then the ceramic coating 496 is also Al2O3. Alternatively, the ceramic coating may be made of the same material as the second ceramic coating 494 (discussed below). In one embodiment, the ceramic coating 496 has a thickness of less than 1 micrometer to up to tens of micrometers.

[0044] When deposited to fill pores up to a depth of about 5 micrometers or greater, the ceramic coating 496 can initially have a thickness of at least 5 micrometers. However, the ceramic coating 496 can be polished to a thickness of 1 micrometer or less. In some cases, the ceramic coating 496 can be substantially polished away, leaving it only within the pores of the filled electrostatic disk 402. The ceramic coating 496 can be polished to an average surface roughness (Ra) of 2 microinches to 12 microinches. In one embodiment, the ceramic coating 496 is polished to a surface roughness of about 4 microinches to 8 microinches. If no overlay ceramic coating is used, the surface of the electrostatic disk 402 can be polished to a surface roughness of 2 microinches to 12 microinches.

[0045] In one embodiment, the ceramic coating 496 (or electrostatic disk 402) is polished to an average surface roughness of approximately 4 microinches to 8 microinches. Lower surface roughness is ideal for minimizing particulate contamination and sealing grain boundaries. Generally, lower surface roughness results in less particulate contamination. Furthermore, by sealing grain boundaries in the ceramic coating 496 and / or electrostatic disk 402, the ceramic coating 496 and / or electrostatic disk 402 become more corrosion-resistant. However, lower surface roughness results in a greater number of nucleation sites for subsequent deposition of the second ceramic coating 494 and / or mesa 492. Additionally, reducing surface roughness reduces the adhesion strength of subsequent coatings on the electrostatic disk 402. Therefore, it has been unexpectedly found that performance degrades when the surfaces of the ceramic coating 496 and / or electrostatic disk 402 are polished to less than approximately 4 microinches.

[0046] The electrostatic chuck 400 also includes a second ceramic coating 494, which in this embodiment is a protective ceramic coating. The second ceramic coating 494 may be disposed on top of the ceramic coating 496, or, if no ceramic coating is deposited, on the electrostatic disk 402. The second ceramic coating 494 protects the electrostatic disk 402 from corrosive chemicals such as hydrogen-based plasma, chlorine-based plasma, and fluorine-based plasma. The second ceramic coating 494 may have a thickness ranging from a few micrometers to several hundred micrometers.

[0047] In one embodiment, the second ceramic coating 494 has a thickness of approximately 5 micrometers to 30 micrometers. The second ceramic coating 494 can be a highly conformal coating, and the surface roughness of the second ceramic coating 494 can substantially match the surface roughness of the ceramic coating 496 and / or the electrostatic disk 402. If the ceramic coating 496 is deposited and polished, the second ceramic coating 494 can be substantially free of pores, pinholes, microcracks, etc. The second ceramic coating 494 can be Al2O3, AlN, Y2O3, or Y3Al5O3. 12 YAG and AlON. In one embodiment, the second ceramic coating 494 is an amorphous YAG having at least 8% by weight of yttrium. In one embodiment, the second ceramic coating 494 has a Vickers hardness of about 9 gigapascals (GPA) (5 kgf). Additionally, in one embodiment, the second ceramic coating 494 has a density of about 4.55 g / cm³, a flexural strength of about 280 MPa, and a flexural strength of about 2.0 MPa.m. 1 / 2 Its fracture toughness, Young's modulus of approximately 160 MPa, and approximately 8.2 x 10⁻⁶ mm² are all characteristic of this material. -6 The coefficient of thermal expansion per kilometer (20–900 °C), thermal conductivity of approximately 12.9 W / mK, and a value greater than 10 W / mK at room temperature. 14 The volume resistivity is Ω·cm, and the coefficient of friction is approximately 0.2–0.3.

[0048] As briefly mentioned above, the structure of the second ceramic coating 494 and the mesa 492 depends at least in part on the roughness of the electrostatic disk 402 and / or the ceramic coating 496 due to a number of roughness-related nucleation sites. When the surface roughness of the electrostatic disk 402 and / or the ceramic coating 496 is less than about 3 microinches, the surface on which the second ceramic coating 494 is deposited has a very large number of nucleation sites. This large number of nucleation sites generates a completely amorphous structure. However, by depositing the second ceramic coating 494 onto a surface with a surface roughness of about 4 to 8 microinches, the second ceramic coating 494 grows or is deposited as an amorphous structure with many vertical fibers, rather than a purely amorphous structure.

[0049] In one embodiment, mesa 492 and ring 493 are deposited on top of the second ceramic coating 494. In such an embodiment, mesa 492 may be made of the same material as the second ceramic coating 494. Alternatively, mesa 492 and ring 493 may be deposited before (and thus below) the second ceramic coating 494. In such an embodiment, mesa 492 and ring 493 may be made of the same material as the electrostatic disk 402 or the same material as the second ceramic coating 494. Mesa may be approximately 3 micrometers to 15 micrometers high (approximately 10 micrometers to 15 micrometers high in one embodiment), and in some embodiments, the diameter is approximately 0.5 mm to 3 mm.

[0050] If the electrostatic chuck 400 is to be repaired after use, the thickness of the second ceramic coating 494 in one embodiment can be at least 20 micrometers, and in another embodiment, approximately 20-30 micrometers. To repair the electrostatic chuck 400, the table 492 can be removed by grinding, and a portion of the second ceramic coating 494 can also be removed by grinding. The amount of material removed during grinding can depend on the amount of curvature on the surface of the electrostatic chuck 400. For example, if the table is 8 micrometers thick and there is 5 micrometer curvature in the electrostatic chuck 400, approximately 15 micrometers can be removed from the surface of the electrostatic chuck 400 to completely remove the table 492 and remove the 5 micrometer curvature. In one embodiment, a thickness of at least 20 micrometers ensures that the underlying electrostatic disk 402 is not ground during repair. Once the table and curvature have been removed by grinding, a new ceramic coating can be applied to the remaining portion of the second ceramic coating 494, and a new table 492 and / or other surface features can be formed on the new ceramic coating as described herein.

[0051] Figure 5 The illustration shows one embodiment of process 500 for manufacturing an electrostatic chuck. Process 500 can be performed to manufacture any electrostatic chuck described in the embodiments herein, such as Figure 4 An electrostatic chuck 400. In block 505 of process 500, an initial ceramic coating (referred to as a cover ceramic coating) is deposited onto the ceramic body of the electrostatic chuck to fill pores, pinholes, microcracks, etc., in the ceramic body. The cover ceramic coating can be formed from the same material as the ceramic body. For example, both the ceramic body and the cover ceramic coating can be AlN or Al2O3. Alternatively, the cover ceramic coating can be formed from the same material as the subsequently deposited protective ceramic coating. For example, both the cover ceramic coating and the protective ceramic coating can be YAG, Y2O3, Al2O3, AlN, or AlON.

[0052] In one embodiment, the overlay ceramic coating is deposited via ion-assisted deposition (IAD). Exemplary IAD methods include deposition processes incorporating ion bombardment, such as evaporation (e.g., activated reactive evaporation (ARE)) and sputtering in the presence of ion bombardment, to form the coating described herein. One illustrative IAD process is electron beam IAD (EB-IAD). Other conformal dense deposition processes that can be used to deposit overlay ceramic coatings include low-pressure plasma spraying (LPPS), plasma spraying physical vapor deposition (PS-PVD), and plasma spraying chemical vapor deposition (PS-CVD), chemical vapor deposition (CVD), physical vapor deposition (PVD), sputtering, or combinations thereof. Other conformal deposition techniques may also be used.

[0053] If an Inductively coupled plasma (IAD) deposition method is used to coat a ceramic substrate, the coating can be formed on the substrate through the accumulation of deposited material in the presence of high-energy particles such as ions. The deposited material can include atoms, ions, radicals, and so on. These high-energy particles can impact and compact the protective film layer during formation. A material source provides the flow of deposited material, while a high-energy particle source provides a flow of high-energy particles, both of which impact the ceramic substrate throughout the IAD process. The high-energy particle source can be oxygen or other ion sources. Other types of high-energy particles can also be provided, such as inert radicals, neutron atoms, and nanoscale particles from particle generation sources (e.g., from plasma, reactive gases, or from the material source providing the deposited material).

[0054] The material source (e.g., the target body) used to provide the deposited material can be a sintered ceramic block corresponding to the same ceramic that constitutes the ceramic coating. Other targets can also be used, such as powders, calcined powders, preformed materials (e.g., materials formed by green pressing or hot pressing), or machined bodies (e.g., molten materials).

[0055] IAD can utilize one or more plasmas or beams (e.g., electron beams) to provide the material and high-energy ion source. Reactive species can also be provided during the deposition of the plasma-resistant coating. In one embodiment, the high-energy particles include at least one of non-reactive species (e.g., Ar) or reactive species (e.g., O). In a further embodiment, reactive species such as CO and halogens (Cl, F, Br, etc.) can also be introduced during the formation of the plasma-resistant coating. When using the IAD process, the high-energy particles can be controlled independently of other deposition parameters via the high-energy ion (or other particle) source. The composition, structure, crystal orientation, and grain size of the ceramic coating can be manipulated based on the energy (e.g., velocity), density, and incident angle of the high-energy ion stream. Other parameters that can be adjusted are the working distance and the incident angle.

[0056] Improved coating properties can be achieved through post-coating heat treatment. For example, post-coating heat treatment can be used to transform amorphous coatings into crystalline coatings with higher corrosion resistance. Another example is improving the adhesion strength of the coating to the substrate by forming reactive zones or transition layers.

[0057] IAD-deposited overlay ceramic coatings can have relatively low film stress (e.g., compared to film stress caused by plasma spraying or sputtering). This relatively low film stress results in a very flat ceramic substrate, with a curvature of less than about 50 micrometers throughout the substrate for a 12-inch diameter ceramic substrate. IAD-deposited overlay ceramic coatings can also have a porosity of less than 1%, and in some embodiments less than about 0.1%. Therefore, IAD-deposited overlay ceramic coatings have a dense structure. Furthermore, IAD-deposited overlay ceramic coatings can have low crack density and high adhesion to the ceramic substrate.

[0058] The ceramic body can be the electrostatic disk described previously. The ceramic body may have undergone some processing, such as for forming embedded electrodes and / or embedded heating elements. The lower surface of the ceramic body can be bonded to the thermally conductive base using a polysiloxane adhesive. In an alternative embodiment, the operation of block 505 is not performed.

[0059] In block 510, the surface of the ceramic body is polished to produce a polished surface with a surface roughness of approximately 2 microinches to 12 microinches. In one embodiment, the surface of the ceramic body is polished to an average surface roughness (Ra) of approximately 4 microinches to 8 microinches. Polishing can reduce and / or almost completely remove the initial ceramic coating, except for partially filling pores, pinholes, etc.

[0060] In block 515, a ceramic coating (e.g., a protective ceramic coating) is deposited or grown on the polished surface of the ceramic body (e.g., over an initial ceramic coating). In one embodiment, the ceramic coating is YAG, Y₂O₃, Al₂O₃, AlN, or AlON. The ceramic coating can be a conformal coating that can be deposited using any deposition technique discussed with reference to block 505. For example, the ceramic coating can be deposited by performing an IAD such as EB-IAD. The ceramic coating can be deposited to a thickness of up to several hundred micrometers. In one embodiment, the ceramic coating is deposited to a thickness of approximately 5 to 30 micrometers. In another embodiment, the ceramic coating is deposited to a thickness of approximately 5 to 10 micrometers. In yet another embodiment, the ceramic coating is deposited to a thickness of approximately 20 to 30 micrometers.

[0061] In block 520, a negative image mask is placed on the coated ceramic body. The negative image mask can be a circular mask with a disk-like shape. The negative image mask can have a diameter slightly smaller than the diameter of the ceramic body. The negative image mask can also include a plurality of through holes, each of which is a negative image of a mesa to be formed on the ceramic body. See below for reference. Figure 6A -C and Figure 7 The negative image mask will be discussed in more detail. In one embodiment, the negative image mask is bonded to the ceramic body by an adhesive (e.g., glued to the ceramic body). Alternatively, the negative image mask can be held in place on the ceramic body by a mechanical retainer.

[0062] In block 525, ceramic material is deposited through the apertures of a negative mask to form a mesa with rounded edges. Additionally, ceramic material can be deposited around the periphery of the ceramic body on exposed portions of the ceramic body to form rings on the ceramic body. The rings can be formed simultaneously with the mesa. The mesa and rings can be conformal and dense, and can be deposited using any deposition technique discussed above with reference to block 505. For example, IAD deposition of the mesa and rings can be used, such as EB-IAD.

[0063] In one embodiment, the aperture in the mask has a flared top and a flared bottom. The flared top acts as a funnel to inject material into the aperture and increase the deposition rate. The flared bottom, combined with the aperture's aspect ratio (e.g., a 1:2 to 2:1 aspect ratio), can function to control the shape of the deposition mesa and / or deposition rings. For example, the aspect ratio combined with the flared bottom can result in a deposited mesa with rounded edges and / or a cap-shaped profile. Furthermore, the flared bottom prevents the mesa from contacting the walls of the aperture. This prevents the mesa from sticking to the mask and from sticking the mask to the ceramic body.

[0064] In one implementation, the inner edge of the ring is rounded, but the outer edge is not. This could be because the shape of the negative mask might cause the inner edge of the ring to become rounded during deposition, but there might be no mask portion at the outer edge of the ring to control the shape of the deposition. Alternatively, the edges of the ring may not be rounded.

[0065] In block 530, remove the mask from the ceramic body. In block 535, polish the countertop and ring. A soft polishing process can be used to polish the countertop. Soft polishing can at least partially polish the walls and top of the countertop.

[0066] In method 500, a protective ceramic coating is deposited first, followed by the deposition of the mesa and ring. However, in an alternative embodiment, the mesa and ring can be deposited before the protective ceramic coating, and the protective ceramic coating can be deposited on top of the mesa. The protective ceramic coating can be highly conformal, so that the shape of the mesa and ring can remain unchanged after the protective ceramic coating is deposited on top of the mesa and ring.

[0067] Figure 6A The diagram illustrates the deposition of ceramic material through a mask 610 to form a circular mesa with rounded edges on the surface of an electrostatic chuck 640. The mask 610 includes a plurality of holes 615. In one embodiment, the mask is approximately 1 mm to 3 mm thick. In another embodiment, the mask is approximately 2 mm thick. In one embodiment, the holes are circular holes with a diameter of approximately 0.5 mm to 3 mm. In another embodiment, the holes have a diameter of approximately 0.5 mm to 2 mm. In another embodiment, the holes have a diameter of approximately 1 mm. In one embodiment, the holes are of uniform size. Alternatively, the holes may have different diameters. In one embodiment, the holes have a width-to-height aspect ratio of 1:2 to 2:1.

[0068] As shown in the figure, in some embodiments, the hole has a flared top end 620 and a flared bottom end 625. The diameter of the flared end can be approximately 30%-70% larger than the diameter of the hole in its narrowest region (e.g., the region vertically centered in the hole). In one embodiment, the diameter of the flared end is approximately 50% larger than the diameter of the hole in its narrowest region. The top and bottom ends can have flares of the same shape and size. Alternatively, the flares at the top end can have a different size and / or shape than the flares at the bottom end.

[0069] A mask 610 is placed on an electrostatic chuck 640, which includes a protective ceramic layer 635 deposited on its surface. Figure 6A In the middle, small terraces with rounded edges 630 have already been deposited. Figure 6B In the middle, deposition continued, and the small platform 630 had transformed into a larger platform 631 with rounded edges. Figure 6C During this process, deposition continues until completion, and the mesa 632 reaches its final dimensions. Notably, due to the flared bottom 625, the mesa 632 does not contact the wall of the hole 615.

[0070] Figure 7The figure shows a top view of a mask 710 used to form mesas and rings on a ceramic body 705 of an electrostatic chuck, according to one embodiment. As shown, the mask 710 is a negative image mask having a first diameter smaller than a second diameter of the ceramic body 705. Therefore, the deposition process allows rings to be formed on the periphery of the ceramic body not covered by the mask 710. The mask 710 further includes a plurality of holes 715. The deposition process forms mesas at each of the holes 715.

[0071] The foregoing description sets forth numerous specific details, such as examples of specific systems, components, methods, etc., to provide a good understanding of several embodiments of the invention. However, it will be apparent to those skilled in the art that at least some embodiments of the invention can be practiced without these specific details. In other instances, well-known components or methods have not been described in detail or have only been presented in simple block diagram form to avoid unnecessarily obscuring the invention. Therefore, the specific details presented are merely exemplary. Specific embodiments may differ from these exemplary details and are still considered to be within the scope of the invention.

[0072] Throughout this specification, the phrase "one embodiment" or "an embodiment" means that a specific feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. Therefore, the phrase "in one embodiment" or "in an embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment. Furthermore, the term "or" is intended to indicate an inclusive rather than an exclusive "or." When the terms "about" or "approximately" are used herein, this is intended to indicate that the presented nominal values ​​are accurate within ±10%.

[0073] Although the operations of the methods described herein are illustrated and described in a specific order, the order of operations for each method can be changed, such that some operations can be performed in reverse order, or that some operations can be performed at least partially concurrently with other operations. In another embodiment, instructions or sub-operations of different operations can be performed intermittently and / or alternately. In one embodiment, multiple metal bonding operations are performed as a single step.

[0074] It should be understood that the above description is intended to be illustrative rather than restrictive. Many other embodiments will become apparent to those skilled in the art upon reading and understanding the above description. Therefore, the scope of the invention should be determined by reference to the appended claims, together with their equivalents.

Claims

1. A coated chamber component, comprising: The main body of the electrostatic disk; A protective ceramic coating is deposited on the surface of the body, the protective ceramic coating being amorphous and comprising 8-20 wt% yttrium, 20-32 wt% aluminum, and 60-70 wt% oxygen. and Multiple countertops, the multiple countertops being above or below the protective ceramic coating, wherein the multiple countertops have rounded edges.

2. The coated chamber component of claim 1, wherein the protective ceramic coating comprises 9-10% by weight of yttrium, 25-26% by weight of aluminum, and 65-66% by weight of oxygen.

3. The coated chamber component as claimed in claim 1, wherein the body is a ceramic body.

4. The coated chamber component of claim 1, wherein the surface of the body is polished, and wherein the protective ceramic coating is conformal and has the same surface roughness as the surface of the body.

5. The coated chamber component of claim 1, wherein the protective ceramic coating comprises amorphous yttrium aluminum garnet (YAG).

6. The coated chamber component of claim 1, wherein the body comprises aluminum nitride or aluminum oxide.

7. The coated chamber component of claim 1, wherein the body comprises a thermally conductive base and a ceramic portion thereon on the thermally conductive base.

8. The coated chamber component of claim 7, wherein the thermally conductive base comprises aluminum or an aluminum alloy.

9. The coated chamber component of claim 1, further comprising: A first ceramic coating is deposited on the surface of the body, wherein the protective ceramic coating covers the first ceramic coating.

10. The coated chamber component of claim 9, wherein the first ceramic coating fills at least one of microcracks, pores, or pinholes in the surface of the body.

11. The coated chamber component of claim 9, wherein the first ceramic coating has a thickness of 1 micrometer or less.

12. The coated chamber component of claim 9, wherein the first ceramic coating comprises alumina.

13. The coated chamber component of claim 1, wherein the protective ceramic coating has an average surface roughness of 2 microinches to 12 microinches.

14. The coated chamber component of claim 1, wherein the protective ceramic coating has an average surface roughness of 4 microinches to 8 microinches.

15. The coated chamber component of claim 1, wherein the protective ceramic coating has a thickness of 5-30 micrometers.

16. The coated chamber component of claim 1, wherein the protective ceramic coating is substantially free of pores, pinholes and microcracks.

17. The coated chamber component of claim 1, wherein the protective ceramic coating has at least one of the following properties: Vickers hardness of 9 gigapascals (GPA) under a test force of 5 kgf; 4.55 g / cm 3 The density; Flexural strength of 280 MPa; 2.0 MPa·m 1 / 2 Fracture toughness; Young's modulus of 160 MPa; 8.2 x 10⁻⁶ was measured in a temperature range of 20–900 °C. -6 Coefficient of thermal expansion / K; Thermal conductivity of 12.9 W / mK; greater than 10 at room temperature 14 Volume resistivity in Ω·cm; or A friction coefficient of 0.2-0.

3.

18. The coated chamber component of claim 1, wherein the protective ceramic coating is an ion-assisted deposition (IAD) coating or a chemical vapor deposition (CVD) coating.

19. The coated chamber component of claim 1, further comprising a plurality of surface features deposited on the protective ceramic coating, the plurality of surface features having rounded edges and deposited through apertures in a negative image mask, wherein the apertures in the negative image mask have flared tops and flared bottoms.

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