Metal-bonded ESC with external ceramic vacuum separation ring for cryogenic service

Abstract

Embodiments of the present disclosure include apparatus for processing substrates. More specifically, embodiments of the present disclosure provide a substrate support assembly including an electrostatic chuck (ESC) assembly. The ESC assembly comprises a cooling base having a top surface and outer diameter sidewalls, and an ESC having a substrate support surface, a bottom surface and outer diameter sidewalls, the bottom surface of the ESC being bonded to the top surface of the cooling base by a metallic bonding layer. The substrate support assembly includes a block ring disposed around the metallic bonding layer.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to apparatuses and methods for fabricating semiconductor substrates. More particularly, embodiments described herein relate to an electrostatic chuck assembly for use in a plasma processing chamber.

Background Art

[0002] Semiconductor substrates are processed for a wide range of applications, including the manufacture of devices for integrated circuits and micro-devices. One such processing apparatus is a plasma processing chamber. During processing, the substrate is positioned on an electrostatic chuck assembly within the plasma processing chamber. The electrostatic chuck assembly may have an electrostatic chuck, a cooling base, a facility plate, and / or a base. The ESC is typically coupled within the electrostatic chuck assembly.

[0003] Plasma is formed within the plasma processing chamber to process the substrate. During plasma processing, precise control is used with respect to the substrate temperature along with the shape of the plasma on the substrate to obtain good and consistent results. Temperature uniformity is provided by a plurality of heaters within the ESC along with the cooling base. The shape of the plasma is affected by the electrodes within the ESC and the shape of the ESC facing the plasma, i.e., the processing ring. A process skew may occur due to plasma coupling to the ESC and / or non-uniformity of temperature across the ESC having an adverse effect on process performance.

[0004] The ESC may require extreme processing temperatures during certain processes. Thus, the ESC can be configured, depending on the processing requirements, particularly for high or low temperatures. For example, in some etching processes, extremely low temperatures are required. At extremely low temperatures, the ESC can operate at temperatures below 0°C. However, typical ESCs not only have a low thermal conductivity but also use an elastomer bond that limits the operating temperature due to a relatively high glass transition temperature, leading to a sharp increase in the Young's modulus at these low temperatures and resulting in the destruction of the ESC bonding material due to shear stress.

[0005] Therefore, an improved electrostatic chuck assembly is needed to improve processing performance at low temperatures. [Overview of the Initiative]

[0006] Embodiments of the present disclosure include apparatus for processing substrates. More specifically, embodiments of the present disclosure provide a substrate support assembly including an electrostatic chuck (ESC) assembly. The ESC assembly includes a cooling base having a top surface and outer diameter sidewalls, and an ESC having a substrate support surface, a bottom surface and outer diameter sidewalls. The bottom surface of the ESC is bonded to the top surface of the cooling base by a metallic bonding layer. The substrate support assembly includes a block ring positioned around the metallic bonding layer.

[0007] Embodiments of the present disclosure further provide a processing chamber. The processing chamber includes a chamber body having a lid, a bottom, and side walls that define an internal space. An electrostatic chuck (ESC) assembly is positioned within the internal space. The ESC assembly includes a cooling base having a top surface and outer diameter side walls, and an ESC having a substrate support surface, a bottom surface, and outer diameter side walls. The bottom surface of the ESC is bonded to the top surface of the cooling base by a metallic bonding layer. The substrate support assembly includes a block ring positioned around the metallic bonding layer.

[0008] Embodiments of the present disclosure may further provide a substrate support assembly including an electrostatic chuck (ESC). The substrate support assembly has a cooling base having a top surface and outer diameter sidewalls. The substrate support assembly further has an ESC having a substrate support surface, a bottom surface and outer diameter sidewalls. The ESC has chuck electrodes disposed therein. An equipment plate is disposed below the cooling base and in contact with the cooling base. A rear gas inlet extends through the substrate support and is configured to supply gas to the surface of the substrate support. A lift pin extends through the ESC, and a lift pin guide extends into the ESC.

[0009] A more detailed description of the Disclosure, which has been briefly summarized above, can be obtained by referring to the embodiments, some of which are shown in the accompanying drawings, so that the features described above may be understood in more detail. However, it should be noted that the accompanying drawings are illustrative embodiments only and should not be considered to limit the scope of the Disclosure, and other equally valid embodiments may also be permitted. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view of an exemplary plasma chamber, including a substrate support assembly, according to one embodiment. [Figure 2] This is a schematic cross-sectional view showing a portion of a substrate support assembly having lift pins according to one embodiment. [Figure 3] This is a schematic cross-sectional view showing another portion of a substrate support assembly having a back gas inlet according to one embodiment. [Figure 4] This is a schematic cross-sectional view showing yet another part of a substrate support assembly having a locking feature according to one embodiment. [Modes for carrying out the invention]

[0011] For ease of understanding, the same reference numerals were used where possible to indicate identical elements common to multiple figures. It is assumed that components and features of one embodiment can be usefully incorporated into other embodiments without further description.

[0012] Embodiments described herein provide a substrate support assembly including a blocking ring that protects the metallic joint between an electrostatic chuck (ESC) and a cooling base. The metallic joint improves thermal conductivity for cooling the substrate during cryogenic processes, while the blocking ring helps protect the metallic joint from the processing environment and prevent arc discharge from the metallic joint.

[0013] The substrate support assemblies described below may be used in etching chambers, as well as in other types of plasma and non-plasma-enhanced processing chambers such as physical vapor deposition chambers, chemical vapor deposition chambers, and ion implantation chambers, and in other systems where protection of the bonding layer positioned between the cooling base and the ESC is desirable.

[0014] Figure 1 is a schematic cross-sectional view of an exemplary plasma chamber 100A including a substrate support assembly 101 according to one embodiment. The substrate support assembly 101 can be used in several types of plasma processing chambers, such as plasma processing chambers, annealing chambers, physical vapor deposition chambers, chemical vapor deposition chambers, and ion implantation chambers, as well as in other systems where it is desirable to protect the adhesive layer in the substrate support assembly 101 from the environmental conditions within the plasma processing chamber 100A. It is also envisioned that this disclosure may be advantageously used in processing chambers that utilize plasma.

[0015] The plasma processing chamber 100A includes a chamber body 102 having side walls 104 surrounding the processing area 109, a bottom 106, and a lid 108. The substrate support assembly 101 is positioned within the processing area 109. The substrate support assembly 101 includes an electrostatic chuck assembly 103 (ESC assembly), an equipment plate 124, an insulating plate 126, a grounding plate 128, and a block ring 145.

[0016] The ESC assembly 103 includes an electrostatic chuck (ESC) 110 and a cooling base 112. In certain embodiments, the ESC assembly 103 may be surrounded by a quartz treatment kit (not shown). The ESC 110 is coupled to the cooling base 112 using a metallic bonding layer 114. The ESC assembly 103 may have lift pins 155 positioned through it and configured to extend above the substrate support surface 116 of the ESC 110. The ESC assembly 103 may have three or more spaced-out lift pins 155 to support a substrate on it.

[0017] The ESC110 includes a substrate support surface 116, a bottom surface 118, and a drop-off formed on the substrate support surface 116, forming a ledge 113 that supports the edge ring 120. The edge ring 120 extends horizontally beyond the outer circumference of the ESC110. In one embodiment, the ESC110 is manufactured from a dielectric 111 having embedded chuck electrodes 129. The dielectric 111 may be a ceramic material (e.g., alumina (Al2O3), aluminum nitride (AlN), or other suitable material). Alternatively, the dielectric 111 of the ESC110 may be manufactured from a polymer such as polyimide, polyetheretherketone, or polyaryletherketone.

[0018] Referring briefly to Figure 2, Figure 2 is a schematic cross-sectional view showing a portion of a substrate support assembly 101, which shows one of the lift pins 155 according to one embodiment. The lift pin 155 extends through a guide 157. The guide 157 extends into the ESC 110 through a cooling base 112, a metallic bonding layer 114.

[0019] The dielectric 111 of the ESC110 has a recess 220 formed in the substrate support surface 116. The recess 220 extends into the dielectric 111 of the ESC110 through the substrate support surface 116. The recess 220 has a bottom 224 and side walls 222 of the recess, along with a pinhead opening 223 formed along the substrate support surface 116 of the dielectric 111. The size and shape of the recess 220 are configured to receive the lift pin head 232 of the lift pin 155.

[0020] During operation, the lift pin 155 is movable vertically through the guide 157 between a raised position and a lowered position. When located in the processing chamber 100, the substrate is supported on the lift pin head 232 when the lift pin 155 extends and lifts the lift pin head 232 above the substrate support surface 116, thereby separating the substrate from the substrate support surface 116 and allowing it to be transported to and from the substrate support assembly 101. When located in the processing chamber 100, the substrate is supported on the substrate support surface 116 when the lift pin 155 is retracted to a position where the lift pin head 232 is below the substrate support surface 116, so that the substrate is placed on the substrate support surface 116.

[0021] The dielectric 111 of the ESC110 has a cavity 210 formed in its bottom surface 118. The cavity 210 extends into the dielectric 111 of the ESC110 through the bottom surface 118. The cavity 210 has a cavity bottom 212 and cavity side walls 211, along with an opening 213 formed along the bottom surface 118 of the dielectric 111.

[0022] The guide 157 extends through the opening 213 to the bottom of the cavity 212. The guide 157 may be formed from a thermoplastic with good chemical resistance, for example, a high melting point above 280 degrees Celsius. For example, the guide 157 may be formed from polyphenylene sulfide (PPS), polyetheretherketone (PEEK), ceramic, or other suitable material.

[0023] In some embodiments, a first gap 252 may be formed between the guide 157 and the cavity bottom 212. A second gap 254 may be formed between the guide 157 and the cavity sidewall 211. The first gap 252 may be between 10 mils and 16 mils. An adhesive material, such as a silicone potting material, may be placed between the guide 157 and the cavity bottom 212 within the first gap 252. An additional adhesive material may be placed between the guide 157 and the cavity sidewall 211 within the second gap 254. The adhesive material reduces stress due to thermal expansion between the guide 157 and the body 201 of the ESC 110.

[0024] Optionally, the seal 241 can be disposed between the ESC 110 and the cooling base 112 adjacent to the metal bonding layer 114 and the guide 157. The seal 241 protects the metal bonding layer 114. In one embodiment, the seal 241 is formed from a silicone sealant, a silicone gasket, a silicone O-ring, or other suitable seal. The seal 241 can alternatively be formed from other suitable materials.

[0025] The path 290 is formed from the substrate support surface 116 to the bottom surface 118 along the recess sidewall 222, the sidewall lift pin 155, the cavity bottom 212, and the cavity sidewall 211. The cavity 210 in the dielectric 111 of the ESC 110 advantageously extends the length of the path 290 compared to a conventional ESC without a cavity. The cavity sidewall 211 increases the length of the interface between the bonding layer and the guide 157 by about 50% to about 150% compared to a conventional ESC. For example, the path 290 increases from about 0.10 inches to 0.20 inches. The path 290 depends on the specific dimensions of the cavity 210, which allows for different diameters of the guide 157 or depths of the cavity 210. The long and non-linear routing of the path 290 further increases the distance from the chamber environment to the metal bonding layer 114, which enhances the protection of the metal bonding layer 114 from the gases present in the chamber environment.

[0026] Returning to FIG. 1, the ESC 110 optionally includes a plurality of backside gas holes 178 that extend through the substrate support surface 116. The backside gas holes 178 are connected to a backside gas source 171. During processing or cleaning, gas can be supplied from the backside gas source 171 through the backside gas holes 178 to the underside of the substrate or cover plate. In one embodiment, the backside gas source 171 supplies an inert gas, such as helium.

[0027] Now, let us look at the schematic cross-sectional view in Figure 3, which shows another part of the substrate support assembly having the rear gas inlet 371. The rear gas hole 178 is fluidly connected to the rear gas source 171 through the rear gas inlet 371. The cartridge 350 is positioned around the rear gas inlet 371. The cartridge 350 has an outer side wall 347, a top surface 356, and a bottom surface 358. A recess 352 extends into the cartridge 350 along the top surface 356. A projection 353 extends outward from the cartridge 350 at the bottom surface 358. The top surface 356 of the cartridge 350 is positioned adjacent to the bottom surface 118 of the ESC 110. The cartridge 350 extends through the cooling base 112 and may extend further into or through the equipment plate 124. The cartridge 350 may be formed of ceramic or other suitable material for operation at temperatures between approximately -60°C and approximately 90°C. For example, the cartridge 350 may be formed from aluminum oxide. The cartridge 350 is configured to be removable, i.e., replaceable. In one embodiment, the cartridge 350 extends into the insulating plate 126. The cartridge 350 is sealed with the ESC 110 and the equipment plate 124 so that back gas can pass through the cartridge 350.

[0028] The porous insert 302 can optionally fluidize the cartridge 350 to the back gas hole 178 of the ESC 110. The porous insert 302 is configured to prevent back gas leakage along the interface between the cartridge 350 and the back gas hole 178. The porous insert 302 also helps to stop the arc discharge path through the helium passage. The porous insert 302 may extend into a recess 352 in the upper surface 356 of the cartridge 350.

[0029] The cartridge 350 provides a seal for maintaining the ESC 110 in a vacuum environment while the equipment plate 124 is maintained at atmospheric pressure. To provide a vacuum seal, a first O-ring 331 is positioned between the cartridge 350 and the ESC 110. In addition, a second O-ring 332 may be positioned between the cartridge 350 and the cooling base 112. In other embodiments, the second O-ring 332 may be positioned between the cartridge 350 and the equipment plate 124.

[0030] The first O-ring 331 may surround the porous insert 302. Alternatively, the first O-ring 331 may have an inward-facing sealing surface that overlaps with the interface between the porous insert 302 and the ESC 110. Optionally, the ESC 110 may have a first sealing groove 311 located within the bottom surface 118 of the ESC 110 for receiving or aligning the first O-ring 331. The first O-ring 331 may be formed from a hybrid material, a silicone material, or other material suitable for cryogenic processes. The first O-ring 331 further protects the metallic bonding layer 114 from the processing environment.

[0031] The second O-ring 332 may surround the downward projection 353 of the cartridge 350. The second O-ring 332 may be formed from a hybrid material, a silicone material, or another material suitable for cryogenic processes. The second O-ring 332 provides a vacuum seal between the cartridge 350 and the substrate support assembly 101.

[0032] Returning to Figure 1, the chuck electrode 129 of the ESC110 may be configured as a unipolar or bipolar electrode, or may have another suitable arrangement. The chuck electrode 129 is connected to a chuck power supply 132 via an RF filter (not shown), which supplies DC power for electrostatically fixing the substrate to the substrate support surface 116 of the ESC110.

[0033] The ESC110 optionally includes one or more internally embedded resistance heaters 134. The resistance heaters 134 are used to raise the temperature of the ESC110 to a processing temperature suitable for processing a substrate placed on the substrate support surface 116. The resistance heaters 134 are connected to an optional heater power supply 136 via the equipment plate 124. The heater power supply 136 can supply power of 500 watts or more to the resistance heaters 134. The heater power supply 136 includes a controller (not shown) used to control the operation of the heater power supply 136, which is generally configured to heat the substrate to a predetermined temperature. In one embodiment, the resistance heaters 134 include a plurality of laterally separated heating zones, and the controller allows at least one zone of the resistance heaters 134 to be preferentially heated over resistance heaters 134 located in one or more of the other zones. For example, the resistance heaters 134 may be arranged concentrically within the plurality of separated heating zones. The resistive heater 134 maintains the substrate at a processing temperature suitable for processing. In one embodiment, the processing temperature is approximately -50°C or lower. For example, the processing temperature is between approximately -50°C and approximately -150°C. In yet another embodiment, the processing temperature is above approximately -50°C. For example, the processing temperature is between -50°C and approximately +150°C.

[0034] Each cooling base 112 includes at least one cooling zone 139 connected to a coolant supply unit 140. If multiple cooling zones 139 exist, they may be arranged concentrically or in other suitable manners. For example, an inner cooling zone may be provided below the substrate support surface 116, and an outer cooling zone may be provided along the outer circumference and optionally extend below the edge ring 120.

[0035] The upper surface 122 of the cooling base 112 is bonded to the bottom surface 118 of the ESC 110 using a metallic bonding layer 114. Due to its high thermal conductivity, the metallic bonding can provide a lower wafer temperature than other elastomer bonding materials for a given coolant temperature. In one embodiment, the metallic bonding layer 114 is formed from an indium-containing material. The metallic bonding layer 114 is approximately 1.90 × 10⁻⁶6 Approximately 1.40 × 10 from PSI 6 The range of PSI, for example, approximately 1.57 × 10⁻⁶. 6 It may have a room temperature Young's modulus of PSI. The metallic bonding layer 114 may have a thermal conductivity in the range of about 75 W / mk to about 90 W / mk, for example, about 86 W / mk. Due to its ductility and thermal conductivity, the metallic bonding is ideal as a compressible thermal interface material. The metal in the adhesive causes only about a 1°C drop across the metallic bonding layer 114, in contrast to conventional adhesives that do not contain metal, which have a drop of about 35°C across the metallic bonding layer 114. Therefore, metallic indium can lower the thermal resistance of the metallic bonding layer 114 by more than 90°C or improve its thermal conductivity to lower the substrate temperature. The improved thermal conductivity can reduce the substrate temperature by about 30% to about 50% compared to conventional designs. Lower substrate temperatures allow for the use of a higher temperature fluid in the cooling base 112 to cool the ESC 110 and, consequently, the substrate. Improved substrate cooling in cryogenic applications reduces the cost of additional cooling by the cooling base 112.

[0036] Since the metallic material of the metallic bonding layer 114 is also conductive, the metallic bonding layer 114 can become an arc point, which can cause problems in high-power ESC designs. To prevent arc discharge, it is desirable to isolate the metallic bonding layer 114 from the process vacuum, but this also prevents metal contamination and bonding corrosion. The block ring 145 protects the metallic bonding layer 114 and the first seal 150. As a result, a metallic-bonded electrostatic chuck (ESC) is created around the outer circumference of the ESC using a ceramic ring, separating the metallic bonding material and cooling plate from the process vacuum. The block ring 145 acts as a plasma blocker, preventing erosion of the metallic bonding layer 114 between the ESC 110 and the cooling base 112, allowing the RF hot cooling base 112 to remain almost completely at atmospheric pressure, thereby favorably mitigating potential arc discharge.

[0037] In one embodiment, the block ring 145 may be positioned between the ESC 110 and the upper surface 117 of the insulating plate 126, which extends beyond the cooling bases 112 on both sides of the substrate support assembly 101. In other words, the block ring 145 is positioned around the outer diameter sidewalls 147 of the cooling bases 112. In one embodiment, the block ring 145 is made of ceramic or other dielectric material. In one embodiment, a first seal 150 forms a vacuum seal between the block ring 145 and the ESC 110. A second seal 152 forms a vacuum seal between the block ring 145 and the insulating plate 126. The first seal 150 may be an O-ring. The first seal 150 may be made of a material suitable for maintaining a vacuum at temperatures below about -60°C (e.g., about -150°C). The first seal 150 may be made of a hybrid material such as silicone / polytetrafluoroethylene (PTFE). The second seal 152 may also be formed from a hybrid material such as silicone / polytetrafluoroethylene (PTFE).

[0038] The outer circumference of the cooling base 112 is completely isolated from the chamber processing gas by a vacuum seal. Alternatively, the block ring 145 may be sealed to the ESC 110 and equipment plate 124 using a bonding material instead of a seal. The bonding material may be a silicone adhesive, epoxy, or other suitable adhesive. Thus, the block ring 145 allows for the utilization of higher pressure, such as ambient pressure, within the portion of the substrate support assembly 101 located inside the block ring 145, which also reduces potential arc discharge within the substrate support assembly 101.

[0039] The equipment plate 124 is positioned below the cooling base 112. The equipment plate 124 is supported by a grounding plate 128 and is configured to facilitate electrical, cooling, heating, and gas connections with the substrate support assembly 101. The grounding plate 128 is supported by the bottom 106 of the processing chamber. An insulating plate 126 insulates the equipment plate 124 from the grounding plate 128. In other words, the insulating plate 126 is positioned above the grounding plate 128 and surrounds the equipment plate 124. There may be a defined optional gap 125 between the equipment plate 124 and the insulating plate 126. The distance of the gap 125 can be between 0.002 inches and 0.010 inches. The gap 125 helps to slow down heat transfer between the equipment plate 124 and the insulating plate 126. The top surface 117 of the insulating plate 126 extends horizontally beyond the cooling base 112. In other words, the insulating plate 126 is wider than the cooling base 112.

[0040] The equipment plate 124 may include optional cooling channels (not shown) which can be connected to an optional coolant supply unit 142. If present, the coolant supply unit 142 provides a coolant that can maintain the equipment plate 124 at an ambient temperature between approximately 25°C and approximately 35°C in one embodiment. The coolant supplied by the coolant supply unit 142 is a thermal conductive fluid, and in some examples, a refrigerant. The coolant supply unit 142 supplies a coolant that circulates through the coolant channels (not shown) of the equipment plate 124. The coolant flowing through the coolant channels allows the equipment plate 124 to be maintained at a predetermined ambient temperature, which helps maintain the insulating plate 126 at a predetermined ambient temperature.

[0041] The insulating plate 126 is positioned below the equipment plate 124. Alternatively, the insulating plate 126 may surround the equipment plate 124. The blocking ring 145 shields the gap between the equipment plate 124 and the cooling base 112, ensuring that the equipment plate 124 does not have a direct line of sight to the side wall of the plasma chamber 100, thereby reducing the possibility of arc discharge between them.

[0042] The components of the substrate support assembly 101 can be connected to each other using fasteners. For example, the grounding plate 128 may be connected to the insulating plate 126 using fasteners, the insulating plate may be connected to the equipment plate 124 using fasteners, and the insulating plate may be connected to the cooling base 112 using fasteners. In one embodiment, a locking feature 137 is provided between the ESC 110 and the cooling base 112. The locking feature 137 can connect the ESC 110 and the cooling base 112 to each other.

[0043] Figure 4 is a schematic cross-sectional view showing yet another part of a substrate support assembly according to one embodiment, showing a locking feature 137. The locking feature 137 has a bushing 412 and an insulator 452. The locking feature 137 may include additional components to prevent movement between the ESC 110 and the cooling base 112 while accommodating the difference in thermal expansion between the ESC 110 and the cooling base 112.

[0044] The ESC110 has an electrode terminal 429. The electrode terminal 429, bushing 412, and insulator 452 fit together to secure the ESC110 to the cooling base 112. For example, the insulator 451 is positioned inside the bushing 412 and around the electrode terminal 429. The electrode terminal 429 is electrically connected to the embedded chuck electrode 129. The electrode terminal 429 is configured to receive power from the chuck power supply 132. The electrode terminal 429 has an upper part 421 and a bottom part 422. In one embodiment, the upper part 421 of the electrode terminal 429 is brazed to an electrical connection in the ESC110. Thus, the electrode terminal 429 is fixed to the ESC110. In one embodiment, the upper part 421 has a larger horizontal cross-section than the horizontal cross-section of the bottom part 422. In the example where the horizontal cross-sections of the bottom 422 and the top 421 are circular, the diameter of the top 421 is larger than the diameter of the bottom 422.

[0045] The bushing 412 is fitted onto the upper surface 442 of the cooling base 112. The bushing 412 may be formed from a non-conductive creep-resistant material such as polyimide, ceramic, or other suitable material. The bushing 412 may have a ring-shaped body 411. The ring shape of the body 411 has an upper outer diameter 415, a bottom outer diameter 413, an upper inner diameter 416, and a bottom inner diameter 417. The radius of the upper inner diameter 416 is smaller than the radius of the bottom inner diameter 417. Similarly, the radius of the upper outer diameter 415 is smaller than the radius of the bottom outer diameter 413. In one embodiment, the bushing 412 is press-fitted into the hole in the cooling base 112. The bottom outer diameter 413 is sized for the hole in the cooling base 112. The upper inner diameter 416 is sized to receive the upper part 421 of the electrode terminal 429. In other words, the bushing 412 is fixed to the cooling base 112.

[0046] The insulator 452 has a body 451. The body 451 is ring-shaped and has an upper part 455 and a bottom part 456. The body has a first outer diameter 461 located close to the bottom part 456, a third outer diameter 463 located close to the upper part 455, and a second outer diameter 462 located between the first outer diameter 461 and the third outer diameter 463. The radius of the first outer diameter 461 is greater than the radius of the second outer diameter 462. The radius of the second outer diameter 462 is greater than the radius of the third outer diameter 463. The first shoulder portion 458 is perpendicular to the first outer diameter 461 and the second outer diameter 462 and is located between the first outer diameter 461 and the second outer diameter 462. The second shoulder portion 464 is perpendicular to the second outer diameter 462 and the third outer diameter 463 and is located between the second outer diameter 462 and the third outer diameter 463. The main body 451 has a first inner diameter 454 located close to the bottom 456 and a second inner diameter 453 located close to the top 455. The first inner diameter 454 has a larger radius than the second inner diameter 453.

[0047] The second inner diameter 453 is sized to receive the upper part 421 of the electrode terminal 429, and the third outer diameter 463 is sized to fit the bottom inner diameter 417 of the bushing 412, creating an overlap 414. The upper part 455 of the insulator 452 contacts the inner shoulder of the bushing 412, which is located between the upper inner diameter 416 and the bottom inner diameter 417. The electrode terminal 429 extends beyond the overlap 414 toward the bottom 456 of the insulator 452, just before the bottom 456. The overlap 414 between the bushing 412 and the insulator 452 electrically couples the electrode terminal 429 to the cooling base 112, preventing arc discharge. The second shoulder 464 is configured to extend downward and outward toward the overlap 414. The first shoulder 458 is located beneath the equipment plate 124, in contact with the equipment plate 124. The first shoulder portion 458 pulls the equipment plate 124 into place, raising it relative to the cooling base 112. Thus, the electrode terminals 429, bushing 412, and insulator 452 of the locking feature 137 hold or lock the equipment plate 124, the cooling base 112, and the ESC 110 together.

[0048] The bottom cavity 486 is located in the first inner diameter 454 of the insulator 452. The bottom 422 of the electrode terminal 429 extends into the cavity 486 to electrically connect to the chuck power supply 132.

[0049] The locking feature 137 optionally includes a seal 484 positioned between the upper surface 431 of the bushing 412 and the ESC 110. The seal 484 may be positioned within a gap 482 formed between the bushing 412 and the ESC 110. Alternatively, or in conjunction with the seal 484, the gap 482 may be filled with silicone or other suitable material to maintain the seal and prevent arc discharge. For example, the gap 482 may be potted with rated silicone at a low temperature of about -60°C.

[0050] Advantageously, the metal bonding improves thermal conductivity for cooling the substrate during cryogenic processes, while the blocking ring protects the metal bonding from the processing environment and helps prevent arc discharge from the metal bonding. Thus, the metal bonding enhances ESC cryogenic performance, while the blocking ring prevents arc discharge and bonding degradation, extending the time between maintenance, and also helps protect the processing environment from chamber contaminants from the metal bonding.

[0051] In addition to the embodiments described above, several additional non-limiting embodiments can be described below.

[0052] Example 1A A substrate support assembly comprising an electrostatic chuck (ESC) assembly, wherein the ESC assembly is Equipment plate and A cooling base is placed on the aforementioned equipment plate and has an upper surface and an outer diameter side wall, An ESC having a substrate support surface, a bottom surface, and a plurality of back gas holes extending through the substrate support surface and fluidly connected to a back gas source through a back gas inlet, A cartridge arranged around the rear gas inlet 371, which extends through the cooling base into the equipment plate, and A substrate support assembly comprising the above.

[0053] Example 1B A substrate support assembly of Example 1A, wherein the cartridge is formed of aluminum oxide and is suitable for operation at temperatures between approximately -60 degrees Celsius and approximately 90 degrees Celsius, and the cartridge is fluid-sealed to the ESC and the equipment plate.

[0054] Example 2A A substrate support assembly comprising an electrostatic chuck (ESC) assembly, The aforementioned ESC assembly A cooling base having an upper surface and an outer diameter side wall, An ESC having a substrate support surface, a bottom surface, electrodes embedded therein, and electrode terminals connected to the electrodes and extending through the bottom surface, The locking feature 137 connects the ESC110 to the cooling base 112. The locking feature is provided, Bushing and An insulator disposed inside the bushing and around the electrode terminals A substrate support assembly comprising the above.

[0055] Example 2B The substrate support assembly of Embodiment 2A, wherein the insulator has an outer diameter sized to fit the inner diameter of the bushing which creates an overlap between the insulators, and the electrode terminals extend toward the bottom of the insulators beyond the overlap and the shortness of the bottom of the insulators.

[0056] While the above description applies to a specific embodiment, other embodiments and further embodiments may be devised without departing from its basic scope, and the scope of such embodiments is defined by the following claims.

Claims

1. A substrate support assembly comprising an electrostatic chuck (ESC) assembly, wherein the ESC assembly is A cooling base having an upper surface and an outer diameter side wall, ESC having a substrate support surface, bottom surface and outer diameter side wall, A metal bonding layer that adheres the bottom surface of the ESC to the upper surface of the cooling base, A block ring arranged around the metal bonding layer A substrate support assembly, including the substrate support assembly.

2. The substrate support assembly according to claim 1, wherein the ESC and the cooling base are configured for cryogenic operation below 0°C.

3. The substrate support assembly according to claim 2, wherein the metal bonding layer is formed from a material containing indium.

4. The substrate support assembly according to claim 3, wherein the block ring is arranged around the outer diameter side wall of the cooling base.

5. The substrate support assembly according to claim 4, wherein the block ring is arranged around the outer diameter side wall of the ESC.

6. The substrate support assembly according to claim 3, wherein the metal bonding layer is formed from indium.

7. The aforementioned metal bonding layer has a thermal conductivity in the range of approximately 75 W / m-k to approximately 90 W / m-k, and is approximately 1.40 × 10 ６ Approximately 1.90 x 10⁻¹⁶ from PSI ６ The substrate support assembly according to claim 3, having a room temperature Young's modulus between PSI.

8. A semiconductor processing chamber, wherein the semiconductor processing chamber is A chamber body having a lid, bottom and side walls that define the internal space, An electrostatic chuck (ESC) assembly disposed within the aforementioned internal space, An equipment plate positioned below a cooling base, wherein the bottom surface of the cooling base extends horizontally beyond the equipment plate, and the equipment plate and The ESC assembly is equipped with, An ESC having a substrate support surface and a bottom surface, A cooling base disposed below the bottom surface of the ESC, wherein a portion of the bottom surface of the ESC extends horizontally beyond the upper surface of the cooling base, A metal bonding layer that connects the ESC to the cooling base, A block ring arranged around the metal bonding layer, A semiconductor processing chamber equipped with the following features.

9. The semiconductor processing chamber according to claim 8, wherein the ESC and the cooling base are configured for cryogenic operation below 0°C.

10. The semiconductor processing chamber according to claim 9, wherein the metallic bonding portion is formed from indium.

11. The semiconductor processing chamber according to claim 10, wherein the block ring is arranged around the outer diameter of the cooling base.

12. The semiconductor processing chamber according to claim 11, wherein the block ring is arranged around the outer diameter of the ESC.

13. The semiconductor processing chamber according to claim 10, wherein the metal bonding portion is formed from indium.

14. The aforementioned metal bonding layer has a thermal conductivity in the range of approximately 75 W / m-k to approximately 90 W / m-k, and is approximately 1.40 × 10 ６ Approximately 1.90 x 10⁻¹⁶ from PSI ６ A semiconductor processing chamber according to claim 10, having a room temperature Young's modulus between PSI.

15. A substrate support assembly, A cooling base having an upper surface and an outer diameter side wall, An electrostatic chuck (ESC) having a substrate support surface, a bottom surface, and an outer diameter side wall, and having chuck electrodes disposed inside, Below the cooling base, an equipment plate is positioned in contact with the cooling base, A back gas inlet extending through the substrate support and configured to supply gas to the surface of the substrate support, A lift pin extending through the aforementioned ESC, A lift pin guide extending into the ESC and A substrate support assembly comprising the above.

16. A lock assembly connected to the chuck electrode in the ESC, wherein the lock assembly is configured to fix the equipment plate in a predetermined position relative to the cooling base and to fix it upward, The substrate support assembly according to claim 15, further comprising the following:

17. A removable ring positioned around the back gas inlet within the substrate support assembly, the removable ring having a recess along the upper surface of the ring and a projection at the bottom surface of the ring that extends outward and away from the ring. The substrate support assembly according to claim 15, further comprising the following:

18. The substrate support assembly according to claim 17, wherein the upper surface of the ring is positioned adjacent to the bottom surface of the ESC, and the ring extends through the cooling base to the equipment plate.

19. A first O-ring is positioned around the recess between the removable ring and the ESC, A second O-ring is positioned around the protrusion between the removable ring and the equipment plate. The substrate support assembly according to claim 18, comprising:

20. The substrate support assembly according to claim 15, wherein the lift pin guide is potted to the ESC.

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