Method and apparatus for mitigating heat transfer in high temperature processes

Abstract

A substrate support assembly including a chuck including one or more plates, a cooling plate or facilities plate attached to a bottom surface of the chuck, the cooling plate or facilities plate including a groove on a top surface of the cooling plate or facilities plate, wherein the groove runs along a periphery of the cooling plate or facilities plate, an o-ring disposed in the groove, and a spacer disposed in the groove, wherein the spacer forms a hermetic seal between the chuck and the o-ring, wherein the spacer includes a first metal alloy.

Description

Attorney Docket No.: 28245.1225 (L1100PCT) METHOD AND APPARATUS FOR MITIGATING HEAT TRANSFER IN HIGH TEMPERATURE PROCESSES TECHNICAL FIELD

[0001] Some embodiments of the present disclosure relate, in general, to a method and apparatus for mitigating heat transfer in high temperature processes. BACKGROUND

[0002] Electrostatic chucks and heaters are widely used to hold substrates, such as semiconductor wafers, during substrate processing in processing chambers. Electrostatic chucks typically include one or more electrodes embedded within a unitary chuck body which includes a dielectric or semi-conductive ceramic material across which an electrostatic clamping field can be generated to chuck a substrate. Heaters generally include heating elements to heat a supported substrate.

[0003] The substrate assembly includes a cooling plate to cool the wafer or substrate mounted on the chuck. Generally, an o-ring or gasket is used to create a vacuum seal between a chamber interior volume and interior volumes within the chuck. The o-ring is generally placed between the chuck and the cooling plate (or facilities plate) to provide the seal. However, for processes where the chuck rises to temperatures over 300oC, this heat is transferred to the o-ring, which can cause the o-ring to fail. For example, the o-ring may crack or melt, thereby breaking the vacuum seal and letting the outside environment leak into the process chamber. SUMMARY

[0004] Some embodiments of the present disclosure described herein cover a substrate support assembly including a chuck including one or more plates, and a cooling plate or facilities plate attached to a bottom surface of the chuck, the cooling plate or facilities plate including a groove on a top surface of the cooling plate or facilities plate. The groove runs along a periphery of the cooling plate or facilities plate, and an o-ring is disposed in the groove, and a spacer disposed in the groove, wherein the spacer forms a hermetic seal between the chuck and the o-ring, wherein the spacer includes a first metal alloy.

[0005] Some embodiments of the present disclosure described herein cover a method includes brazing a spacer to a bottom of a chuck, wherein the spacer includes a first metal alloy, placing an o-ring in a groove in a cooling plate or facilities plate, and disposing aAttorney Docket No.: 28245.1225 (L1100PCT) spacer between the chuck and the cooling plate or facilities plate to form a hermetic seal between the chuck and the cooling plate or the facilities plate.

[0006] Some embodiments of the present disclosure described herein cover a spacer for mitigating heat transfer between an electrostatic chuck and a cooling plate or a facilities plate, the spacer including a metal alloy. The spacer is at least partially coated with aluminum or magnesium. The spacer has a substantially C-shaped, S-shaped, Z-shaped, or epsilon-shaped cross section. The spacer further includes a first material having a first thermal conductivity and second material having a second thermal conductivity, wherein the second thermal conductivity is lower than the first thermal conductivity. The spacer includes at least one of a polyimide, Hastelloy®, Kovar®, or a para-aramid. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present disclosure is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that different references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one.

[0008] FIG.1 depicts a sectional side view of one embodiment of a processing chamber;

[0009] FIG.2 depicts a sectional side view of one embodiment of a substrate support in a process chamber;

[0010] FIGS.3A-3B depict sectional side views of embodiments of a substrate support in a process chamber; and

[0011] FIGS.4A-4B depict sectional side views of embodiments of a substrate support in a process chamber. DETAILED DESCRIPTION OF EMBODIMENTS

[0012] Generally, an o-ring or gasket is used to create a vacuum seal between a chamber interior volume and interior volumes within the chuck. The o-ring is generally placed between the chuck and the cooling plate (or facilities plate) to provide the seal. To maintain the vacuum seal under high temperature conditions, it is essential to mitigate heat transfer from the electrostatic chuck to the O-ring, keeping the O-ring within its thermal tolerance. Aspects of the present disclosure address the above need by providing a spacer to mitigate heat transfer from the chuck to the o-ring and provide a hermetic seal between the chuck and the o-ring.Attorney Docket No.: 28245.1225 (L1100PCT)

[0013] Embodiments of the present disclosure provide a substrate support assembly including an electrostatic chuck and a cooling plate or a facilities plate. The electrostatic chuck includes one or more plates, and the cooling plate or facilities plate is attached to a bottom surface of the chuck. The cooling plate or facilities plate includes a groove on a top surface of the cooling plate or facilities plate. The groove runs along a periphery of the cooling plate or facilities plate and an o-ring is disposed in the groove. Additionally, a spacer disposed in the groove such that the spacer forms a hermetic seal between the chuck and the o-ring, wherein the spacer includes a first metal alloy.

[0014] A top portion of the spacer is brazed to the bottom surface of the chuck with a second metal alloy. The second metal alloy includes at least one of aluminum, an aluminum alloy, magnesium, a magnesium alloy, or a magnesium-aluminum alloy. The spacer is at least partially coated with aluminum or magnesium. The substrate support assembly may further include a second dielectric material bonded to a bottom surface of the spacer, wherein the second dielectric material interfaces with the o-ring. The spacer has a substantially C-shaped, S-shaped, Z-shaped, or epsilon-shaped cross section. The spacer further includes a first material band having a first thermal conductivity and second material band having a second thermal conductivity. In some embodiments, the second thermal conductivity is lower than the first thermal conductivity. In some embodiments, the second thermal conductivity is higher than the first thermal conductivity. The spacer includes at least one of a polyimide, Hastelloy®, Kovar®, or a para-aramid.

[0015] Embodiments of the present disclosure provide a method of forming a substrate support assembly. The method includes brazing a spacer to a bottom of an electrostatic chuck. The spacer includes a first metal alloy. The method further includes placing an o-ring in a groove in a cooling plate or facilities plate and disposing the spacer between the chuck and the cooling plate or facilities plate to form a hermetic seal between the chuck and the cooling plate or the facilities plate. The method further includes at least partially coating the spacer with aluminum or magnesium. The method further includes disposing a dielectric material with a low thermal conductivity between a bottom portion of the spacer and the cooling plate, wherein the dielectric material interfaces with the o-ring.

[0016] Embodiments of the present disclosure provide a spacer for mitigating heat transfer between an electrostatic chuck and a cooling plate or a facilities plate, the spacer including a metal alloy. The spacer is at least partially coated with aluminum or magnesium. The spacer has a substantially C-shaped, S-shaped, Z-shaped, or epsilon-shaped cross section. The spacer further includes a first material having a first thermal conductivity and secondAttorney Docket No.: 28245.1225 (L1100PCT) material having a second thermal conductivity, wherein the second thermal conductivity is lower than the first thermal conductivity. The spacer includes at least one of a polyimide, Hastelloy®, Kovar®, or a para-aramid.

[0017] Advantages of the disclosed embodiments include a substrate support assembly that can withstand high temperatures (e.g., 300oC or more) without sacrificing the integrity of the o-ring and maintain a hermetic seal between the chuck and the cooling plate. In some embodiments, the substrate support assembly is able to withstand higher temperatures (e.g., 350oC, 400oC, 450oC, or more).

[0018] FIG.1 is a sectional view of one embodiment of a processing chamber 100 having a substrate support 150 disposed therein. The processing chamber 100 may be any type of processing chamber, such as a deposition chamber, an etch chamber, an oxidation chamber, an implant chamber, and so on. While the substrate support 150 is described as being an electrostatic chuck assembly or a heater assembly in some embodiments, the substrate support may be replaced with other types of substrate support assemblies, such as a vacuum chuck assembly, a deposition heater assembly, and so on. In one embodiment, the substrate support 150 includes a puck assembly 166 having an upper puck plate bonded to a lower puck plate, as will be discussed in greater detail below. The substrate support 150 may additionally include more than two plates, where each plate may include zero or more different functional elements of the substrate support (e.g., chucking electrodes, radiofrequency (RF) electrodes, main heating electrodes, auxiliary heating electrodes, cooling channels, and so on). The puck assembly 166 can be coupled to a cooling plate by multiple fasteners, or by a bond such as a metal bond, an organic bond, a polymer bond, etc., or a combination thereof.

[0019] The processing chamber 100 includes a chamber body 102 and a lid 104 that enclose an interior volume 106. The chamber body 102 may be fabricated from aluminum, stainless steel, or other suitable material. The chamber body 102 generally includes sidewalls 108 and a bottom 110. An outer liner 116 may be disposed adjacent to the side walls 108 to protect the chamber body 102. The outer liner 116 may be fabricated and / or coated with a plasma or halogen-containing gas resistant material. In one embodiment, the outer liner 116 is fabricated from aluminum oxide. In another embodiment, the outer liner 116 is fabricated from or coated with yttria, yttrium alloy, or an oxide thereof.

[0020] An exhaust port 126 may be defined in the chamber body 102 and may couple the interior volume 106 to a pump system 128. The pump system 128 may include one or moreAttorney Docket No.: 28245.1225 (L1100PCT) pumps and throttle valves utilized to evacuate and regulate the pressure of the interior volume 106 of the processing chamber 100.

[0021] The lid 104 may be supported on the sidewall 108 of the chamber body 102. The lid 104 may be opened to allow access to the interior volume 106 of the processing chamber 100, and may provide a seal for the processing chamber 100 while closed. A gas panel 158 may be coupled to the processing chamber 100 to provide process and / or cleaning gases to the interior volume 106 through a gas distribution assembly 130 or nozzle that may be part of the lid 104. Examples of processing gases may be used to process in the processing chamber including halogen-containing gas, such as C2F6, SF6, SiCl4, HBr, NF3, CF4, CHF3, CH2F3, Cl2and SiF4, among others, and other gases such as O2, or N2O. Examples of carrier gases include N2, He, Ar, and other gases inert to process gases (e.g., non-reactive gases). The gas distribution assembly 130 may have multiple apertures 132 on the downstream surface of the gas distribution assembly 130 to direct the gas flow to the surface of the substrate 144. Additionally, or alternatively, the gas distribution assembly 130 can have a center hole where gases are fed through a ceramic gas nozzle. The gas distribution assembly 130 may be fabricated and / or coated by a ceramic material, such as silicon carbide, Yttrium oxide, etc. to provide resistance to halogen-containing chemistries to prevent the gas distribution assembly 130 from corrosion.

[0022] In embodiments, the substrate support 150 is disposed in the interior volume 106 of the processing chamber 100 below the gas distribution assembly 130. The substrate support 150 holds a substrate 144 during processing. An inner liner 118 may be coated on the periphery of the substrate support 150. The inner liner 118 may be a halogen-containing gas resist material such as those discussed with reference to the outer liner 116. In one embodiment, the inner liner 118 may be fabricated from the same materials of the outer liner 116.

[0023] In one embodiment, the substrate support 150 is part of a greater assembly 148 that includes the substrate support 150 as well as a mounting plate 162 supporting a pedestal 152. In one embodiment, the substrate support 150 further includes a thermally conductive base referred to herein as a cooling plate 164 coupled to a puck assembly (also referred to as a puck plate assembly) 166. The cooling plate 164 may be coupled to the puck assembly 166 by multiple fasteners and / or by a bonding layer. The substrate support 150 described in embodiments may be used for Johnsen-Rahbek and / or Coulombic electrostatic chucking in embodiments. The substrate support 150 may additionally or alternatively be used as a heater,Attorney Docket No.: 28245.1225 (L1100PCT) such as a deposition heater that is configured to heat a support substrate 144 during a deposition process.

[0024] In one embodiment, a protective ring 146 is disposed over a portion of the puck assembly 166 at an outer perimeter of the puck assembly 166. In one embodiment, the puck assembly 166 (or one or more plates of the puck assembly 166) is coated with a protective layer 136. Alternatively, the puck assembly 166 may not be coated by a protective layer 136. The protective layer 136 may be a ceramic such as Y2O3(yttria or yttrium oxide), Y4Al2O9(YAM), Al2O3(alumina), Y3Al5O12(YAG), YAlO3 (YAP), Quartz, SiC (silicon carbide), Si3N4(silicon nitride) Sialon, AlN (aluminum nitride), AlON (aluminum oxynitride), TiO2(titania), ZrO2(zirconia), TiC (titanium carbide), ZrC (zirconium carbide), TiN (titanium nitride), TiCN (titanium carbon nitride), Y2O3stabilized ZrO2(YSZ), and so on. The protective layer may also be a ceramic composite such as Y3Al5O12distributed in Al2O3matrix, Y2O3-ZrO2solid solution or a SiC-Si3N4solid solution. The protective layer may also be a ceramic composite that includes a yttrium oxide (also known as yttria and Y2O3) containing solid solution. For example, the protective layer may be a ceramic composite that is composed of a compound Y4Al2O9(YAM) and a solid solution Y2-xZrxO3(Y2O3-ZrO2solid solution). Note that pure yttrium oxide as well as yttrium oxide containing solid solutions may be doped with one or more of ZrO2, Al2O3, SiO2, B2O3, Er2O3, Nd2O3, Nb2O5, CeO2, Sm2O3, Yb2O3, or other oxides. Also note that pure Aluminum Nitride as well as doped Aluminum Nitride with one or more of ZrO2, Al2O3, SiO2, B2O3, Er2O3, Nd2O3, Nb2O5, CeO2, Sm2O3, Yb2O3, or other oxides may be used. Alternatively, the protective layer may be sapphire or MgAlON.

[0025] In embodiments, the puck assembly 166 includes an upper puck plate (not shown) and a lower puck plate (not shown) bonded by a metal and / or organic bond. The puck assembly 166 may also include more than two plates. The upper puck plate and / or one or more other plates may be formed from a monolithic dielectric or electrically insulative material (e.g., having an electrical resistivity of greater than 1014Ohm·meter) that is usable for semiconductor processes at temperatures of 150° C and above. In one embodiment, the upper puck plate and / or other plate(s) is composed of materials usable from about 20° C to about 500° C. In one embodiment, the upper puck plate and / or other plate(s) is AlN or another ceramic, or boron nitride, silicon carbide, beryllium oxide, sapphire, gallium nitride, zinc oxide, or a combination thereof. The AlN upper puck plate and / or other plate(s) may be undoped or may be doped. For example, the AlN may be doped with Samarium oxide (Sm2O3), Cerium oxide (CeO2), Titanium dioxide (TiO2), or a transition metal oxide. In oneAttorney Docket No.: 28245.1225 (L1100PCT) embodiment, the lower puck plate and / or other plate(s) is Al2O3. The Al2O3lower puck plate and / or other plate(s) may be undoped or may be doped. For example, the Al2O3may be doped with Titanium dioxide (TiO2) or a transition metal oxide. In some embodiments, each of the plates of the puck assembly 166 may be formed of a same ceramic. In other embodiments, different plates of the puck assembly 166 may be formed of different ceramics.

[0026] The lower puck plate and / or one or more other plates may have a coefficient of thermal expansion that is matched or close to a coefficient of thermal expansion of the upper puck plate. In one embodiment, the lower puck plate and / or other plate(s) is a SiC porous body that is infiltrated with an AlSi alloy (referred to as AlSiSiC). The lower puck plate and / or other plate(s) may alternatively be AlN or Al2O3or other ceramic material or a combination thereof (e.g., aluminum oxynitride (ALON)). In one embodiment, the lower puck plate and / or other plate(s) is undoped AlN or undoped Al2O3. In one embodiment, the lower puck plate and / or other plate(s) is composed of the same material as the upper puck plate. The AlSiSiC material, AlN or Al2O3may be used, for example, in reactive etch environments or in inert environments.

[0027] In one embodiment, the lower puck plate and / or other plate(s) is Molybdenum. Molybdenum may be used, for example, if the puck assembly 166 is to be used in an inert environment. Examples of inert environments include environments in which inert gases such as Ar, O2, N, etc. are flowed. Molybdenum may be used, for example, if the puck assembly 166 is to chuck a substrate for metal deposition. Molybdenum may also be used for the lower puck plate and / or other plate(s) for applications in a corrosive environment (e.g., etch applications). In such an embodiment, exposed surfaces of the lower puck plate and / or other plate(s) may be coated with a plasma resistant coating after the lower puck plate is bonded to the upper puck plate. The plasma coating may be performed via a plasma spray process. The plasma resistant coating may cover, for example, side walls of the lower puck plate and an exposed horizontal step of the lower puck plate. In one embodiment, the plasma resistant coating is Al2O3. Alternatively, the plasma resistant coating may be Y2O3or a Y2O3containing oxide. Alternatively, the plasma resistant coating may be any of the materials described with reference to protective layer 136.

[0028] The mounting plate 162 is coupled to the bottom 110 of the chamber body 102 and includes passages for routing utilities (e.g., fluids, power lines, sensor leads, etc.) to the cooling plate 164 and the puck assembly 166. The cooling plate 164 and / or puck assembly 166 may include one or more embedded heating elements 176, embedded thermal isolators 174, conduits 168, 170 to control a lateral temperature profile of the substrate support 148,Attorney Docket No.: 28245.1225 (L1100PCT) and / or other functional elements. In embodiments, different functions of the puck assembly 166 may be divided across multiple plates. For example, one plate may include RF electrodes, one plate may include primary heating electrodes, one plate may include auxiliary heating electrodes, and so on. In some embodiments, multiple functions are provided by a single plate. For example, one plate of puck assembly 166 may include both RF electrodes and chucking electrodes. In one embodiment, a thermal gasket 138 and / or o-ring is disposed on at least a portion of the cooling plate 164.

[0029] The conduits 168, 170 may be fluidly coupled to a fluid source 172 that circulates a temperature regulating fluid through the conduits 168, 170. The embedded thermal isolators 174 may be disposed between the conduits 168, 170 in one embodiment. The embedded heating elements 176 are regulated by a heater power source 178. The embedded heating elements 176 may be included in one plate (e.g., top plate) of puck assembly 166. The conduits 168, 170 and embedded heating elements 176 may be utilized to control the temperature of the puck assembly 166, which may heat and / or cool the puck assembly 166 and a substrate (e.g., a wafer) being processed. In one embodiment, the puck assembly 166 includes two separate heating zones that can maintain distinct temperatures. In another embodiment, the puck assembly 166 includes four different heating zones that can maintain distinct temperatures. In other embodiments, the puck assembly 166 includes more than four heating zones (e.g., 8, 16, 32, 64, 128, 216, etc. pixelate heating zones). The temperature of the puck assembly 166 and the thermally conductive base 164 may be monitored using multiple temperature sensors 190, 192, which may be monitored using a controller 195. The temperature sensors 190, 192 may be included in one plate of puck assembly 166 and / or in multiple plates of the puck assembly 166, which may be a same plate or plates or different plate or plates from the plate(s) containing the heating elements 176.

[0030] The puck assembly 166 may further include multiple gas passages such as grooves, mesas, seal bands, and other surface features that may be formed in an upper surface of a topmost plate of the puck assembly 166. The gas passages may be fluidly coupled to a source of a heat transfer (or backside) gas, such as He via holes drilled in the plates of the puck assembly 166. In operation, the backside gas may be provided at controlled pressure into the gas passages to enhance the heat transfer between the puck assembly 166 and the substrate 144.

[0031] In one embodiment, the puck assembly 166 includes at least one clamping electrode 180 controlled by a chucking power source 182. The clamping electrode 180 may be included in one plate of puck assembly 166. The clamping electrode 180 (also referred toAttorney Docket No.: 28245.1225 (L1100PCT) as a chucking electrode) may further be coupled to one or more RF power sources 184, 186 through a matching circuit 188 for maintaining a plasma formed from process and / or other gases within the processing chamber 100. In one embodiment, a different RF electrode or set of electrodes are connected to one or more RF power sources 184, 186 and used for maintaining a plasma. The RF electrode(s) may be included in one plate of puck assembly 166. The one or more RF power sources 184, 186 may be capable of producing an RF signal having a frequency from about 50 kHz to about 3 GHz and a power of up to about 10,000 Watts. In one embodiment, an RF signal is applied to the metal base, an alternating current (AC) is applied to the heater and a direct current (DC) is applied to the clamping electrode 180.

[0032] FIG.2 depicts a cross-sectional view of one embodiment of the substrate support 150. The substrate support 150 includes the puck assembly 166 and the cooling plate 164 attached to the puck assembly 166. As shown, an o-ring 214 or gasket may be placed on (e.g., vulcanized to) the cooling plate 164 along a perimeter of a top side of the cooling plate 164. Alternatively, the o-ring 214 or gasket may be disposed on the top side of the cooling plate 164 without being vulcanized thereto. Some embodiments are discussed herein with reference to o-rings that are vulcanized to at least a portion of the cooling plate 164. In one embodiment, the o-ring 214 is a perfluoropolymer (PFP) o-ring or polyimide o-ring. Alternatively, other types of o-rings may be used. In one embodiment, thermally insulating o- rings or gaskets are used. The o-ring 214 may be a stepped o-ring or gasket having a first step at a first thickness and a second step at a second thickness. This may facilitate uniform tightening of fasteners by causing the amount of force used to tighten the fasteners to increase dramatically after a set amount of compression of the o-ring 214 or gasket. In embodiments, the o-ring 214 is disposed in a circular groove that may extend along a periphery of the cold plate (or at a certain radius from a center of the cold plate).

[0033] Additional o-rings (not shown) or gaskets may also be vulcanized to and / or placed on the top side of the cooling plate around a hole 280 at a center of the cooling plate 164 through which cables are run. Other smaller o-rings or gaskets may also be vulcanized to and / or placed on the cooling plate 164 around other openings, around lift pins, and so forth. These o-rings may also be disposed in circular grooves that encircle the hole 280, lift pins, and / or other openings. Examples of PFPs usable for the o-ring 214 are Dupont’s™ ECCtreme™, Dupont’s KALREZ® and Daikin’s® DUPRA™. The o-ring 214 may provide a vacuum seal between a chamber interior volume and interior volumes within the substrateAttorney Docket No.: 28245.1225 (L1100PCT) support 150. The interior volumes within the substrate support 150 may include open spaces within the pedestal 152 for routing conduits and wiring.

[0034] A spacer may be placed within groove 300, which is described in further detail in Figs.3A-4B. A top portion of the spacer may be brazed to the bottom surface of the chuck and a bottom portion of the spacer may be supported by a material having a low thermal conductivity, such as alumina. Alternatively, the spacer may be brazed on the top portion, and the bottom portion may rest on the o-ring in order to provide a hermetic seal between the chuck and the cooling plate. In one embodiment, the puck assembly 166 has a disc-like shape having an annular periphery that may substantially match the shape and size of the substrate 144 positioned thereon. An upper surface of the puck assembly 166 may have an outer ring 216, multiple mesas 210, and channels 212 between the mesas 210. In one embodiment, the puck assembly 166 includes an upper puck plate 230 bonded to the lower puck plate 232 by a metal bond, a ceramic bond, an organic bond, a polymer bond, or other type of bond. Alternatively, the puck assembly 166 may be a single plate.

[0035] In one embodiment, the material used for the lower puck plate 232 may be suitably chosen so that a coefficient of thermal expansion (CTE) for the lower puck plate 232 material substantially matches the CTE of the electrically insulative upper puck plate 230 material in order to minimize CTE mismatch and avoid thermo-mechanical stresses which may damage the puck 166 during thermal cycling. In one embodiment, the lower puck plate 232 is Molybdenum. In one embodiment, the lower puck plate 232 is alumina. In one embodiment, the lower puck plate 232 is AlN or Al2O3. The lower puck plate may be composed of a same material as the upper puck plate, but may have a different purity level, a different grain size, different amounts of dopants, and so on to provide different material properties for the lower puck plate than the upper puck plate in embodiments.

[0036] The cooling plate 164 attached below the puck 166 may have a disc-like main portion and an annular flange extending outwardly from the main portion and positioned on the pedestal 152. In one embodiment, the cooling plate 164 may be fabricated by a metal, such as aluminum or stainless steel or other suitable materials. Alternatively, the cooling plate 164 may be fabricated by a composite ceramic, such as an aluminum-silicon alloy infiltrated SiC or Molybdenum to match a thermal expansion coefficient of the puck 166. The cooling plate 164 should provide good strength and durability as well as heat transfer properties.

[0037] In some embodiments, the upper puck plate 230 and the lower puck plate 232 are bonded together by a bond 250, which may be a metal bond, an organic bond, a polymerAttorney Docket No.: 28245.1225 (L1100PCT) bond, a ceramic bond, or other type of bond. In one embodiment, diffusion bonding is used as a method of metal bonding plates of the substrate support 150 together. In one embodiment, the upper puck plate 230 and the lower puck plate 232 comprise materials which include aluminum (e.g., AlN or Al2O3). Bond 250 may be a metal or organic bond 250 that may include an “interlayer” of aluminum foil or other metal foil which is placed in a bonding region between the upper puck plate 230 and the lower puck plate 232. Pressure and heat may be applied to form a diffusion bond between the aluminum foil and the upper puck plate 230 and between the aluminum foil and lower puck plate 232. In another embodiment, the diffusion bond may be formed using other interlayer materials which are selected based upon the materials used for upper puck plate 230 and lower puck plate 232. In another embodiment, the upper puck plate 230 may be directly bonded to the lower puck plate 232 using direct diffusion bonding in which no interlayer is used to form the bond. An organic bond, ceramic bond, polymer bond, or other type of bond may also be formed to bond the plates together.

[0038] The upper puck plate 230 includes mesas 210, channels 212, and an outer ring 216. In one embodiment, the upper puck plate 230 includes functional elements such as clamping electrodes 180 and / or one or more heating elements 176. Alternatively, the clamping electrodes 180 and / or heating elements 176 may be disposed in different plates (e.g., heating elements and / or clamping electrodes may be disposed in lower puck plate 232). In some embodiments, lower puck plate 232 may include one or more functional elements 220 (e.g., heating elements, clamping electrodes, and / or RF electrodes). The clamping electrodes 180 may be coupled to a chucking power source 182, and / or to an RF plasma power supply 184 and / or an RF bias power supply 186 via a matching circuit 188. The upper puck plate 230, lower puck plate 232 and / or other plates may additionally include gas delivery holes (not shown) through which a gas supply 240 pumps a backside gas such as He. Additionally, the upper puck plate 230, lower puck plate 232 and / or other plates may additionally include one or more cooling holes (not shown) for a cooling fluid to flow therethrough.

[0039] The upper puck plate 230 and / or lower puck plate 232 may have a thickness of about 1-25 mm or more. In one embodiment, the upper puck plate 230 has a thickness of about 3 mm. The clamping electrodes 180 may be located about 0.25 mm from an upper surface of the upper puck plate 230, and the heating elements 176 may be located about 1 mm under the clamping electrodes 180. The heating elements 176 may be screen printed heating elements having a thickness of about 10-200 microns in some embodiments. Alternatively,Attorney Docket No.: 28245.1225 (L1100PCT) the heating elements may be resistive coils that use about 1-3 mm of thickness of the upper puck plate 230 in some embodiments. In such an embodiment, the upper puck plate 230 may have a minimum thickness of about 5 mm. In one embodiment, the lower puck plate 232 has a thickness of about 1-25 mm. In some embodiments, the upper and / or lower puck plates have thicknesses ranging from 1 mm to 10 mm, 2 mm to 8 mm, or other thicknesses. In embodiments, different puck plates may have the same or different thicknesses, which may range from 1-25 mm, for example. In embodiments, interface layers or bonding layers between puck plates may have a thickness of about 25 microns to about 1 mm (e.g., 1-14 mil).

[0040] The heating elements 176 may be electrically connected to a heater power source 178 for heating the upper puck plate 230. The upper puck plate 230 may include electrically insulative materials such as AlN. The lower puck plate 232 and upper puck plate 232 (and / or one or more other plates) may be made of the same materials and / or different materials. In one embodiment, the lower puck plate 232 is made of materials which are different from the materials used for the upper puck plate 230. The lower puck plate 232 is coupled to and in thermal communication with a cooling plate 164 having one or more conduits 170 (also referred to herein as cooling channels) in fluid communication with fluid source 172.

[0041] In one embodiment (not shown), the cooling plate 164 includes a base portion. In one embodiment, o-ring 214 may be vulcanized to the base portion. In one embodiment, the cooling plate 164 includes a spring loaded inner heat sink connected to the base portion by one or more springs. The springs apply a force to press the inner heat sink against the puck 166. A surface of the heat sink may have a predetermined roughness and / or surface features (e.g., mesas) that control heat transfer properties between the puck 166 and the heat sink. Additionally, the material of the heat sink may affect the heat transfer properties. For example, an aluminum heat sink will transfer heat better than a stainless steel heat sink. In one embodiment, the heat sink includes a grafoil layer on an upper surface of the heat sink.

[0042] FIGS.3A-3B depict sectional side views of embodiments of a substrate support 150 in a process chamber. The substrate support assembly 150 may include an electrostatic chuck 166 and a cooling plate 164 or a facilities plate. A facilities plate may refer to a component or assembly that houses or organizes various utility connections and services required for the operation of the chamber. This may include connections for gases, vacuum, cooling fluids, electrical services, and other necessary utilities. The plate may be designed to integrate seamlessly with the process chamber, ensuring that all connections are reliable andAttorney Docket No.: 28245.1225 (L1100PCT) secure. This integration may be made for maintaining the integrity of the process environment, whether it's a vacuum, a controlled atmosphere, or a specific temperature. The materials used for the facilities plate may be compatible with the process environment. This includes materials that are resistant to corrosion, able to withstand high temperatures, or non- reactive with process gases.

[0043] The electrostatic chuck 166 includes one or more plates, and the cooling plate or facilities plate (or base plate) 164 is attached to a bottom surface of the chuck. The cooling plate or facilities plate includes a groove 300 on a top surface of the cooling plate 164 or facilities plate. FIG.3B illustrates a cross-sectional view of the groove 300 formed on a top surface of the cooling plate 164. The groove 300 runs along a periphery of the cooling plate 164 or facilities plate and an o-ring 310 is disposed in the groove. Additionally, a spacer 304 disposed in the groove such that the spacer 304 forms a hermetic seal between the chuck 166 and the o-ring 310. In some embodiments, the spacer may include a metal alloy.

[0044] A top portion of the spacer 304 is brazed to the bottom surface of the chuck with a second metal alloy 306. The second metal alloy 306 may include at least one of aluminum, an aluminum alloy, magnesium, a magnesium alloy, or a magnesium-aluminum alloy. In some embodiments, the spacer 304 is at least partially coated with aluminum or magnesium. In some embodiments, the substrate support assembly may further include a second dielectric material 308 bonded to a bottom surface of the spacer, wherein the second dielectric material 308 interfaces with the o-ring 310. In some embodiments, the spacer 304 has a substantially C-shaped, S-shaped, Z-shaped, or epsilon-shaped cross section. In some embodiments, the spacer further includes a first material band having a first thermal conductivity and second material band having a second thermal conductivity. In some embodiments, the second thermal conductivity is lower than the first thermal conductivity. In some embodiments, the second thermal conductivity is higher than the first thermal conductivity. The spacer 304 includes at least one of a polyimide, Hastelloy®, Kovar®, or a para-aramid.

[0045] Embodiments of the present disclosure provide a method of forming a substrate support assembly. The method includes brazing a spacer to a bottom of an electrostatic chuck. The spacer includes a first metal alloy. The method further includes placing an o-ring in a groove in a cooling plate or facilities plate and disposing the spacer between the chuck and the cooling plate or facilities plate to form a hermetic seal between the chuck and the cooling plate or the facilities plate. The method further includes at least partially coating the spacer with aluminum or magnesium. The method further includes disposing a dielectricAttorney Docket No.: 28245.1225 (L1100PCT) material with a low thermal conductivity between a bottom portion of the spacer and the cooling plate, wherein the dielectric material interfaces with the o-ring.

[0046] FIGS.4A-4B depict sectional side views of embodiments of a substrate support 150 in a process chamber. FIG.4B illustrates a cross-sectional view of a groove 400 formed on a top surface of the cooling plate 164. The electrostatic chuck 166 includes one or more plates, and the cooling plate or facilities plate 164 is attached to a bottom surface of the chuck. The cooling plate or facilities plate includes a groove 400 on a top surface of the cooling plate 164 or facilities plate. The groove 400 runs along a periphery of the cooling plate 164 or facilities plate and an o-ring 410 is disposed in the groove. Additionally, a spacer 402 disposed in the groove such that the spacer 402 forms a hermetic seal between the chuck 166 and the o-ring 410. In some embodiments, the spacer may include a metal alloy.

[0047] A top portion of the spacer 402 is brazed to the bottom surface of the chuck with a second metal alloy 406. The second metal alloy 406 may include at least one of aluminum, an aluminum alloy, magnesium, a magnesium alloy, or a magnesium-aluminum alloy. In some embodiments, the spacer 402 is at least partially coated with aluminum or magnesium. In some embodiments, the substrate support assembly may further include a second dielectric material 408 bonded to a bottom surface of the spacer, wherein the second dielectric material 308 interfaces with the o-ring 410.

[0048] In some embodiments, the spacer 402 has a substantially C-shaped, S-shaped, Z- shaped, or epsilon-shaped cross section. The spacer mitigates heat transfer from the high- temperature chuck to the O-ring by lengthening the thermal path between them. By employing shapes like C-shaped, S-shaped, Z-shaped, or epsilon-shaped configurations, the spacer increases the distance heat must travel, thereby reducing the thermal energy reaching the O-ring and protecting it from excessive temperatures. In some embodiments, the spacer 402 has a cross-section thickness equal to or less than 0.5 mm. In other embodiments, the cross-section thickness of the spacer 402 is greater than 0.5 mm to suit an application.

[0049] In some embodiments, the spacer further includes a first material band 404 having a first thermal conductivity and second material band 414 having a second thermal conductivity. In some embodiments, the second thermal conductivity is lower than the first thermal conductivity. In some embodiments, the second thermal conductivity is higher than the first thermal conductivity. This type of alternating bands with different thermal conductivities helps mitigate heat transfer between the chuck and the cooling plate. Although spacer 402 is illustrated as having a helical or a zigzag or an accordion-type structure, the metal alloy may be shaped in any manner suitable to mitigate the heat transfer. In someAttorney Docket No.: 28245.1225 (L1100PCT) embodiments, the spacer 304 includes at least one of a polyimide, Hastelloy®, Kovar®, or a para-aramid.

[0050] In some embodiments, the spacer 402 may be at least partially coated with aluminum or magnesium. In some embodiments, the spacer 402 may have a substantially C- shaped, S-shaped, Z-shaped, or epsilon-shaped cross section. In some embodiments, the spacer 402 may further includes a first material having a first thermal conductivity and second material having a second thermal conductivity, wherein the second thermal conductivity is lower than the first thermal conductivity. In some embodiments, the spacer 402 may include at least one of a polyimide, Hastelloy®, Kovar®, or a para-aramid. Other materials having low thermal conductivity and ultra-high strength may be used to form the spacer in the above embodiments.

[0051] The disclosed embodiments allow for a substrate support assembly that can withstand high temperatures (e.g., 300oC or more) without sacrificing the integrity of the o- ring and maintaining a hermetic seal between the chuck and the cooling plate. In some embodiments, the substrate support assembly is able to withstand higher temperatures (e.g., 350oC, 400oC, 450oC, or more). In some embodiments, the spacer can allow for a temperature drop between the chuck and the o-ring of over 25 degrees Celsius. In some embodiments, the spacer can provide for a temperature drop of 40 to 50 degrees Celsius, between the chuck and the O-ring

[0052] The preceding description sets forth numerous specific details such as examples of specific systems, components, methods, and so forth, in order to provide a good understanding of several embodiments of the present disclosure. It will be apparent to one skilled in the art, however, that at least some embodiments of the present disclosure may be practiced without these specific details. In other instances, well-known components or methods are not described in detail or are presented in simple block diagram format in order to avoid unnecessarily obscuring the present disclosure. Thus, the specific details set forth are merely exemplary. Particular implementations may vary from these exemplary details and still be contemplated to be within the scope of the present disclosure.

[0053] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrase “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. In addition, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” When the term “about” orAttorney Docket No.: 28245.1225 (L1100PCT) “approximately” is used herein, this is intended to mean that the nominal value presented is precise within ±10%.

[0054] Although the operations of the methods herein are shown and described in a particular order, the order of the operations of each method may be altered so that certain operations may be performed in an inverse order or so that certain operation may be performed, at least in part, concurrently with other operations. In another embodiment, instructions or sub-operations of distinct operations may be in an intermittent and / or alternating manner. In one embodiment, multiple metal bonding operations are performed as a single step.

[0055] It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading and understanding the above description. The scope of the disclosure should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

Attorney Docket No.: 28245.1225 (L1100PCT) CLAIMS What is claimed is:

1. A substrate support assembly comprising: a chuck comprising one or more plates; a cooling plate or facilities plate attached to a bottom surface of the chuck, the cooling plate or facilities plate comprising a groove on a top surface of the cooling plate or facilities plate, wherein the groove runs along a periphery of the cooling plate or facilities plate; an o-ring disposed in the groove; and a spacer disposed in the groove, wherein the spacer forms a hermetic seal between the chuck and the o-ring, wherein the spacer comprises a first metal alloy.

2. The substrate support assembly of claim 1, wherein a top portion of the spacer is brazed to the bottom surface of the chuck with a second metal alloy.

3. The substrate support assembly of claim 2, wherein the second metal alloy comprises at least one of aluminum, an aluminum alloy, magnesium, a magnesium alloy, or a magnesium-aluminum alloy.

4. The substrate support assembly of claim 1, wherein the spacer is at least partially coated with aluminum or magnesium.

5. The substrate support assembly of claim 1, further comprising: a second dielectric material bonded to a bottom surface of the spacer, wherein the second dielectric material interfaces with the o-ring.

6. The substrate support assembly of claim 1, wherein the spacer has a substantially C-shaped, S-shaped, Z-shaped, or epsilon-shaped cross section.

7. The substrate support assembly of claim 1, wherein the spacer further comprises a first material band having a first thermal conductivity and second material band having a second thermal conductivity, wherein the second thermal conductivity is lower than the first thermal conductivity.Attorney Docket No.: 28245.1225 (L1100PCT) 8. The substrate support assembly of claim 1, wherein the spacer comprises at least one of a polyimide, Hastelloy®, Kovar®, or a para-aramid.

9. A method comprising: brazing a spacer to a bottom of a chuck, wherein the spacer comprises a first metal alloy; placing an o-ring in a groove in a cooling plate or facilities plate; and disposing a spacer between the chuck and the cooling plate or facilities plate to form a hermetic seal between the chuck and the cooling plate or the facilities plate.

10. The method of claim 9, further comprising: at least partially coating the spacer with aluminum or magnesium.

11. The method of claim 9, wherein the spacer is brazed to the bottom of the chuck using a second metal alloy, and wherein the second metal alloy comprises at least one of aluminum, an aluminum alloy, magnesium, a magnesium alloy, or a magnesium-aluminum alloy.

12. The method of claim 9, further comprising: disposing a dielectric material with a low thermal conductivity between a bottom portion of the spacer and the cooling plate, wherein the dielectric material interfaces with the o-ring.

13. A processing chamber, comprising: a chamber body and a lid enclosing an interior volume; a pump system, wherein the pump system comprises one or more pumps and one or more throttle valves to evacuate and regulate a pressure of the interior volume; a gas distribution assembly; and a substrate support assembly, the substrate support assembly comprising: a chuck comprising one or more plates; a cooling plate or facilities plate attached to a bottom surface of the chuck, the cooling plate or facilities plate comprising a groove on a top surface of the cooling plate or facilities plate, wherein the groove runs along a periphery of the cooling plate or facilities plate; an o-ring disposed in the groove; andAttorney Docket No.: 28245.1225 (L1100PCT) a spacer disposed in the groove, wherein the spacer mitigates heat transfer between the chuck and the cooling plate or the facilities plate, wherein the spacer forms a hermetic seal between the chuck and the o-ring, wherein the spacer comprises a first metal alloy.

14. The processing chamber of claim 13, wherein the spacer is at least partially coated with aluminum or magnesium.

15. The processing chamber of claim 13, wherein the spacer has a substantially C- shaped, S-shaped, Z-shaped, or epsilon-shaped cross section.

16. The processing chamber of claim 13, wherein the spacer further comprises a first material having a first thermal conductivity and second material having a second thermal conductivity, wherein the second thermal conductivity is lower than the first thermal conductivity.

17. The processing chamber of claim 13, wherein the spacer comprises at least one of a polyimide, Hastelloy®, Kovar®, or a para-aramid.

18. The processing chamber of claim 13, wherein the spacer has a cross-section thickness of 0.5mm.

19. The processing chamber of claim 13, wherein a top portion of the spacer is brazed to the bottom surface of the chuck with a second metal alloy.

20. The processing chamber of claim 19, wherein the second metal alloy comprises at least one of aluminum, an aluminum alloy, magnesium, a magnesium alloy, or a magnesium- aluminum alloy.

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