High-temperature micro-area electrostatic chuck

Abstract

Implementations described herein provide a substrate support assembly. The substrate support assembly has a first ceramic plate having a workpiece support surface and a bottom surface. The first ceramic plate has a plurality of auxiliary heaters each forming a plurality of microzones. The substrate support assembly has a second ceramic plate having an upper surface and a lower surface. A first metal joint layer is disposed between the bottom surface of the first ceramic plate and the upper surface of the second ceramic plate. A third ceramic plate has a top portion and a bottom portion. The third ceramic plate has a main heater. A second metal joint layer is disposed between the lower surface of the second ceramic plate and the top portion of the third ceramic plate.

Description

[0001] background

[0002] field

[0003] The embodiments described herein generally relate to semiconductor manufacturing, and more specifically to a high-temperature substrate support assembly having multiple micro-area heaters. Background Technology

[0004] Reliably manufacturing nanoscale features and even smaller features is a key technological challenge for next-generation very large-scale integrated circuit (VLSI) and ultra-large-scale integrated circuit (ULSI) semiconductor devices. However, as circuit technology advances, the size of VLSI and ULSI interconnect technologies shrinks, placing additional demands on process capabilities. Reliably forming gate structures on substrates is crucial for the success of VLSI and ULSI, and for continued efforts to improve circuit density and the quality of individual substrates and dies.

[0005] To reduce production costs, integrated circuit (IC) manufacturers demand high throughput and optimal device yield and performance per silicon substrate processed. Some manufacturing technologies being explored for next-generation devices currently under development require processing thin films on substrates at temperatures exceeding 300 degrees Celsius and high bias power. High bias power can improve the roughness and morphology of the thin films on the substrate. However, high bias power also generates heat, which, if uncontrolled, can undesirably limit the choice of materials and the processing methods that can be performed on the substrate.

[0006] Some of these high-temperature and high-power manufacturing technologies are performed within a processing chamber, where the substrate being processed is held in place using electrostatic chucks. A conventional electrostatic chuck (ESC) is part of a substrate support assembly, and the chuck has multiple heating zones to ensure uniform processing across the entire ESC surface. However, because heat moves unintentionally and laterally between adjacent areas, heat application or outward dissipation between adjacent heating zones often results in undesirable heat distribution. Therefore, achieving the desired heat distribution and processing results for the ESC is difficult.

[0007] Therefore, an improved substrate support assembly with multiple heaters is needed. Summary of the Invention

[0008] The embodiments described herein provide a substrate support assembly. The substrate support assembly has a first ceramic plate having a workpiece support surface and a bottom surface. The first ceramic plate has a plurality of auxiliary heaters, each auxiliary heater forming a plurality of microregions. The substrate support assembly has a second ceramic plate having an upper surface and a lower surface. A first metal bonding layer is disposed between the bottom surface of the first ceramic plate and the upper surface of the second ceramic plate. A third ceramic plate has a top portion and a bottom portion. The third ceramic plate has a main heater. A second metal bonding layer is disposed between the lower surface of the second ceramic plate and the top portion of the third ceramic plate. Attached Figure Description

[0009] The above-described features of the invention, which have been briefly summarized above, can be understood in more detail by referring to the embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the drawings illustrate only typical embodiments of the invention and should therefore not be considered as limiting the scope of the invention, as other equivalent embodiments are permissible.

[0010] Figure 1 This is a schematic side view of a cross-section of a processing chamber, one embodiment of which has a substrate support assembly.

[0011] Figure 1A This is a schematic cross-sectional view of the electrostatic chuck of the substrate support assembly, showing multiple auxiliary heaters.

[0012] Figure 2 This is a schematic partial side view of a substrate support assembly based on an example.

[0013] Figure 3 This is a schematic partial side view of a substrate support assembly based on another example.

[0014] Figure 4 This is a schematic partial side view of a substrate support assembly based on yet another example.

[0015] To facilitate understanding, the same reference numerals have been used wherever possible to indicate common elements in the figures. It is contemplated that elements disclosed in one embodiment may be advantageously used in other embodiments without further description. Detailed Implementation

[0016] The embodiments described herein provide a substrate support assembly that enables an electrostatic chuck (ESC) with multiple heaters that generate micro-area effects to operate at high temperatures. Here, a micro-area refers to a temperature-discretely controllable region of the ESC, wherein in the examples disclosed below, there may be 50 to 150 or more micro-areas on the ESC. High temperature refers to a temperature exceeding about 150 degrees Celsius, for example, a temperature exceeding about 300 degrees Celsius. The examples of the substrate support assembly provided below include a cooling plate and an electrostatic chuck, which are separated by a bonding layer and a thermal interface layer. The thermal interface layer is formed of glass capable of generating a temperature gradient between about 150°C and about 260°C across the entire thermal interface. The arrangement of the thermal interface between the electrostatic chuck and the cooling base reduces temperature loss and thermalsmearing between micro-areas in the electrostatic chuck.

[0017] Although the substrate support assembly is described below in the context of the etching process chamber, the substrate support assembly can be used in other types of plasma process chambers, such as physical vapor deposition chambers, chemical vapor deposition chambers, ion implantation chambers, and other systems in which high-temperature (i.e., temperatures exceeding 150 degrees Celsius) processes occur.

[0018] Figure 1 This is a schematic cross-sectional view of an exemplary plasma processing chamber 100, shown configured as an etching chamber with a substrate support assembly 126. The substrate support assembly 126 can be used in other 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 other systems requiring the ability to control the processing uniformity of surfaces or workpieces (such as substrates). Controlling the dielectric properties tan(δ) (i.e., dielectric loss) or ρ (i.e., volume resistivity) of the substrate support assembly 126 over an elevated temperature range advantageously enables azimuth processing control (i.e., processing uniformity) of the substrate 124 disposed on the substrate support assembly 126 during processing.

[0019] The plasma processing chamber 100 includes a chamber body 102 having sidewalls 104, a bottom, and a cover 108 surrounding an internal processing region 110. An injection device 112 is coupled to the sidewalls 104 and / or the cover 108 of the chamber body 102. A gas panel 114 is coupled to the injection device 112 to allow processing gas to be supplied to the processing region 110. The injection device 112 may be one or more nozzles or inlets, or alternatively, a spray head. Processing gas, along with any processing byproducts, is removed from the processing region 110 through an exhaust port 128 formed in the sidewalls 104 or the bottom 106 of the chamber body 102. The exhaust port 128 is coupled to a pumping system 132, which includes a throttle valve and a pump for controlling the vacuum level within the processing region 110.

[0020] Power can be supplied to the process gas to form plasma within the processing zone 110. The process gas can be powered by capacitively or inductively coupling RF power to it. Figure 1 In the depicted embodiment, a plurality of coils 116 are disposed above the cover 108 of the plasma processing chamber 100 and coupled to an RF power supply 120 via a matching circuit. Power is applied to the plurality of coils 116, which are power-inductively coupled to the processing gas, to form plasma within the processing region 110.

[0021] A substrate support assembly 126 is disposed in the processing area 110 below the injection device 112. The substrate support assembly 126 includes an electrostatic chuck (ESC) 174 and a cooling base 130. The cooling base 130 may optionally be supported by a base plate 176. The base plate 176 is supported by either a sidewall 104 or a bottom 106 of the processing chamber 100. Additionally, the substrate support assembly 126 may include a facility plate 145 and / or an insulating plate (not shown) disposed between the cooling base 130 and the base plate 176 to facilitate electrical, cooling, and gas connections with the substrate support assembly 126.

[0022] The cooling base 130 is formed of a metallic material or other suitable material. For example, the cooling base 130 may be formed of aluminum (Al). The cooling base 130 includes cooling channels 190 formed therein. The cooling channels 190 are connected to a heat transfer fluid source 122 via a fluid transfer conduit 192. The heat transfer fluid source 122 provides a heat transfer fluid, such as a liquid, a gas, or a combination thereof, which circulates through the cooling channels 190 in the cooling base 130. In one embodiment, the heat transfer fluid circulating through the cooling channels 190 of the cooling base 130 maintains the cooling base 130 at a temperature between about 30 degrees Celsius and about 120 degrees Celsius, or below 90 degrees Celsius.

[0023] ESC 174 includes one or more adsorption electrodes 186 disposed in a dielectric 175. The dielectric 175 has a workpiece support surface 137 and a bottom surface 133 opposite to the workpiece support surface 137. The dielectric 175 of ESC 174 is made of a ceramic material such as alumina (Al2O3), aluminum nitride (AlN), or other suitable materials. Alternatively, the dielectric 175 may be made of a polymer such as polyimide, polyetheretherketone, polyaryletherketone, etc.

[0024] Dielectric 175 includes one or more main resistance heaters 188 embedded therein. The main resistance heaters 188 may alternatively be located in another portion of the substrate support assembly 126. The main resistance heaters 188 are used to raise the temperature of the substrate support assembly 126 to a temperature suitable for processing the substrate 124 disposed on the workpiece support surface 137 of the substrate support assembly 126. The main resistance heaters 188 are coupled to a heater power supply 189 via a facility plate 145. The heater power supply 189 supplies power to the main resistance heaters 188. The operation of the heater power supply 189 is controlled using a controller, which is typically configured to heat the substrate 124 to a predefined temperature. In one embodiment, the main resistance heaters 188 are arranged in a plurality of laterally separated heating zones, wherein the controller causes at least one zone of the main resistance heaters 188 to be preferentially heated relative to main resistance heaters 188 located in one or more other zones. For example, the main resistance heaters 188 may be concentrically arranged in a plurality of radially separated main heater zones (in Figure 1A (shown as 181 in the diagram). In one example, the main resistance heater 188 is arranged in four concentric main heater regions 181: a first main heater region 1811, a second main heater region 1812, a third main heater region 1813, and a fourth main heater region 1814. The main resistance heater 188 can maintain the substrate 124 at a temperature suitable for processing, such as between about 180 degrees Celsius and about 500 degrees Celsius, such as greater than about 250 degrees Celsius, such as between about 250 degrees Celsius and about 350 degrees Celsius or above.

[0025] The ESC 174 also includes multiple auxiliary heaters 140. The number of auxiliary heaters 140 can be an order of magnitude larger than the number of main resistance heaters 188. The auxiliary heaters 140 are used to control the temperature of the ESC 174 at a microscopic level, such as ±5 degrees Celsius, while the main resistance heaters 188 control the temperature of the ESC 174 at a macroscopic level. The ESC 174 also has multiple microzones, such as 50 to 150 microzones or more, which are temperature-controlled by the auxiliary heaters 140. The auxiliary heaters 140 create temperature control in small, discrete locations (i.e., microzones on the ESC 174).

[0026] Briefly go to Figure 1A , Figure 1A This is a schematic cross-sectional view of ESC 174 of the substrate support assembly 126, showing a plurality of auxiliary heaters 140. ESC 174 illustrates one embodiment of the plurality of auxiliary heaters 140. The auxiliary heaters 140 can be patterned to efficiently generate heat distribution along the surface of the substrate support assembly 126. The pattern can be symmetrical about a midpoint, while providing gaps in and around the vent 128 for lifting pins or other mechanical, fluid, or electrical connections. The auxiliary heaters 140 are arranged in a plurality of cells (i.e., micro-regions 199). It is envisioned that each auxiliary heater 140 occupies its own single micro-region 199. A thermal choke 118 is disposed between each adjacent micro-region 199. Additionally, the thermal choke 118 can be disposed along the outer periphery of ESC 174. The thermal choke 118 restricts heat transfer from adjacent micro-regions to prevent heat smearing, and each micro-region 199 is under actual thermal control via its respective auxiliary heater 140.

[0027] The number of micro-regions 199 shown is for illustrative purposes only, and it is conceivable that the number of micro-regions 199 will exceed 50 or more, such as 150 or more. Therefore, the number of auxiliary heaters 140 located on the entire substrate support assembly 126 can easily exceed several hundred. Each micro-region 199 of the auxiliary heater 140 occupies a single main heater region 181 within the main heater region 181. The thermal choke 118 or boundary of the micro-region 199 coincides with the boundary 182 of the corresponding main heater region 181 (e.g., the first main heater region 1811), such that the micro-region 199 is entirely contained within only the first main heater region 1811 and does not extend into the second main heater region 1812.

[0028] Each auxiliary heater 140 has a resistor 191 terminating at a terminal. As current enters one terminal and exits the other, the current travels across the wires of the resistor and generates heat. The heat dissipated by the resistor 191 is proportional to the square of the current flowing through the resistor 191. Power design densities can range from about 1 watt / unit to about 100 watts / unit, such as 10 watts / unit.

[0029] Resistor 191 may have a film thickness and a wire thickness configured to efficiently provide heat when current flows through resistor 191. Increasing the wire thickness of resistor 191 can reduce the resistance value R of resistor 191. The wire thickness can range from about 0.05 mm to about 0.5 mm for tungsten wire and from about 0.5 mm to about 1 mm for nichrome wire. Recalling the formula R = ρ·l / A, it can be seen that the material, wire length, and wire thickness of resistor 191 can be selected to control cost, power consumption, and heat generated by each auxiliary heater 140. In one embodiment, resistor 191 is made of tungsten, has a wire thickness of about 0.08 mm, and a resistance of about 90 ohms at 10 watts.

[0030] return Figure 1 Each auxiliary heater 140 can be controlled by a controller 142. The controller 142 can turn on a single auxiliary heater 140; or, the controller 142 can turn on multiple auxiliary heaters grouped together. In this way, the temperature can be precisely controlled at independent locations along the micro-regions 199 formed in the ESC 174, such independent locations being limited to concentric rings known in the art. Although the pattern shown consists of small units, the pattern can alternatively have larger and / or smaller units, extend to the edges, or have other forms to form 150 or more discrete micro-regions 199.

[0031] ESC 174 typically includes an adsorption electrode 186 embedded in a dielectric 175. The adsorption electrode 186 may be configured as a unipolar or bipolar electrode, or other suitable configuration. The adsorption electrode 186 is coupled to an adsorption power supply 187 via an RF filter, which provides DC power to electrostatically attach the substrate 124 to the workpiece support surface 137 of the ESC 174. The RF filter prevents the RF power used to form plasma (not shown) within the plasma processing chamber 100 from damaging electrical equipment or causing electrical hazards outside the chamber.

[0032] The workpiece support surface 137 of ESC 174 includes a gas channel (not shown) for supplying back-side heat transfer gas to the interstitial space defined between the substrate 124 and the workpiece support surface 137 of ESC 174. ESC 174 also includes a lift pin hole for receiving a lift pin (not shown) for raising the substrate 124 above the workpiece support surface 137 of ESC 174 to facilitate robotic transport into and out of the plasma processing chamber 100.

[0033] A bonding layer 150 is disposed below the ESC 174 and secures the ESC 174 to the cooling base 130. In other embodiments, the bonding layer 150 is disposed between the ESC 174 and a lower plate disposed between the ESC 174 and the cooling base 130. The bonding layer 150 may comprise a glass material and / or be formed from a glass plate. For example, the bonding layer 150 may comprise nickel gallium oxide (NGO) silicon oxide, polyimide, silicon, or other suitable materials. The bonding layer 150 provides a thermal interruption between the ESC 174 and the cooling base 130 to improve the high-temperature microarea effect by reducing heat loss from the microarea 199 to the cooling base 130. The bonding layer 150 may have a thermal conductivity between about 0.1 W / mK and about 5 W / mK. The composition of the bonding layer 150 is selected to compensate for the difference in thermal expansion between the ESC 174 and the lower portion of the substrate support assembly 126, such as, for example, the cooling base 130. For high-temperature applications, such as substrate processing above 300 degrees Celsius, the bonding layer 150 may be formed of a polymer instead of silicon. The bonding layer 150 is formed of a glass material with the same thermal expansion and thermal conductivity to prevent bending due to mismatch or temperature gradient between ESC 174 and cooling base 130.

[0034] Figure 2 This is a schematic partial side view of an example substrate support assembly 200. The substrate support assembly 200 can be used instead of the substrate support assembly 126 in the aforementioned processing chamber 100. The substrate support assembly 200 is formed by a stack of layers including a ceramic ESC 210, a metal bonding member 220, a ceramic plate 230, a thermal interface layer 240, and a cooling base 250. The cooling base 250 can be substantially similar to... Figure 1 The cooling base 130 is shown. The ceramic ESC 210 is configured to operate at temperatures up to and exceeding 300 degrees Celsius. The substrate support assembly 200 utilizes a thermal interface layer 240 to reduce heat transfer between the ESC 210 and the cooling base 250, while preventing warping, bending, or other undesirable thermally induced movement in the layer stack forming the substrate support assembly 200. The thermal interface layer 240 also prevents the cooling base 250 from coating discrete temperature microregions 199 within the ESC 210. For example, the thermal interface layer 240 prevents heat from being transferred from the auxiliary heater 140 to the cooling base 250, rather than along the workpiece support surface 137 to the microregions 199.

[0035] The ceramic ESC 210 has a substrate support surface 212 and a lower surface 214. The ceramic ESC 210 has a body formed of a ceramic material such as alumina or other suitable material. The ceramic ESC 210 has a first coefficient of thermal expansion. The ceramic ESC 210 has one or more electrodes 202 and a plurality of heaters 204 disposed in the body. The electrodes 202 are configured to adsorb the substrate onto the substrate support surface 212. The plurality of heaters 204 include auxiliary heaters for generating a plurality of microregions 199 for discretely heating the substrate support surface 212, and thus discretely heating the substrate supported on the substrate support surface 212.

[0036] Metal connector 220 has a top surface 222 and a bottom surface 224. The top surface 222 is disposed abutting against the bottom surface 224 of ESC 210. The bottom surface 224 is disposed abutting against ceramic plate 230. Metal connector 220 can also be used as an RF electrode to supplement or replace electrode 202. Metal connector 220 can be in a sheet. Metal connector 220 can have one or more holes 225 formed therein. The material forming the holes 225 of metal connector 220 can extend in one or more flaps 221. For example, metal connector 220 can have one or more small slits forming a circular pattern, such that when flaps 221 are pushed out of the sheet of metal connector 220 from a plane (such as orthogonally), the slits form flaps 221 around the holes 225. The connection that enables metal connector 220 to be used as an RF electrode is discussed below.

[0037] The ceramic plate 230 has a top surface 232 and a bottom surface 234. The top surface 232 contacts the bottom surface 224 of the metal connector 220. The bottom surface 234 contacts the thermal interface layer 240. A cavity 235 with sidewalls 231 is formed into the ceramic plate 230 through the top surface 232. A hole 238 extends from the bottom of the cavity 235 out of the bottom surface 224 of the ceramic plate 230. A fin 221 of the metal connector 220 extends downward to the sidewalls 231 of the cavity 235. The ceramic plate 230 may be formed of alumina or other suitable materials. The ceramic plate 230 has a second coefficient of thermal expansion, i.e., a larger coefficient of expansion along the thickness of the ceramic plate 230. The second coefficient of thermal expansion of the ceramic plate 230 is equal to or greater than the first coefficient of thermal expansion of ESC 210.

[0038] Alternatively or additionally, the coefficient of thermal expansion increases from ESC 210 to ceramic plate 230. A higher coefficient of thermal expansion than the first prevents the substrate support assembly 200 from bending during heating. In some examples, an auxiliary heater 140 may be disposed in the ceramic plate 230 instead of ESC 210. In another example, the auxiliary heater 140 is disposed in ESC 210, while the main resistance heater 188B is located in the ceramic plate 230. In yet another example, the ceramic plate 230 is formed of a first ceramic plate 230A and a second ceramic plate 230B. The first ceramic plate 230A and the second ceramic plate 230B are formed of the same material selection as the ceramic plate 230 (such as AlO or Al2O3). However, it should be understood that the first ceramic plate 230A and the second ceramic plate 230B need not be formed of the same material. In one example, the thickness of the first ceramic plate 230A and the second ceramic plate 230B is between about 5 mm and about 7 mm. The first ceramic plate 230A and the second ceramic plate 230B need not have the same thickness. For example, the first ceramic plate 230A may have a thickness of approximately 6 mm, and the second ceramic plate 230B may have a thickness of approximately 6.5 mm. A second metal connector 220B is coupled to the first ceramic plate 230A and the second ceramic plate 230B. The second metal connector 220B is envisioned to be similar to the metal connector 220. However, the second metal connector 220B may have an Al or other material independent of and different from the metal connector 220. The main resistance heater 188B may have four zones and be disposed in either the first ceramic plate 230A or the second ceramic plate 230B. In one example, the main resistance heater 188B is disposed in the second ceramic plate 230B. In such an example, an auxiliary heater is disposed in ESC 210, gas distribution is disposed in the first ceramic plate 230A, and the four-zone main resistance heater 188B is disposed in the second ceramic plate 230B.

[0039] The metal connector 220 does not extend along the entire length of the ceramic plate 230 or the ceramic ESC 210. A first gap 270 extends between the outer edge of the metal connector 220 and the outer periphery of the ceramic ESC 210 and the ceramic plate 230. The first gap 270 is sized to accommodate a seal 292 or such as an O-ring. The seal 292 forms a seal between the ceramic ESC 210 and the ceramic plate 230. The seal 292 protects the metal connector 220 from exposure to plasma and chemicals present in the processing chamber environment, thereby extending the life of the metal connector 220.

[0040] In one example, the thermal interface layer 240 may be formed of SiO2, NGO, or other suitable materials. The thermal interface layer 240 may resemble the metallic bond 220 and include an interface pad 245. The interface pad 245 is made of materials such as GRAFOIL. TMIt is made of one or more of the following: flexible graphite sheets, polyimide, metal, silicone, or fluoropolymer. The thickness of the interface gasket 245 is in the range of about 0.1 mm to about 2 mm. The interface gasket 245 allows a temperature difference of up to 300 degrees Celsius between the ceramic plate 230 and the cooling base 250 without bending or cracking in the ceramic plate 230.

[0041] The thermal interface layer 240 has an upper surface 242 and a lower surface 244. The upper surface 242 contacts the bottom surface 234 of the ceramic plate 230. The lower surface 244 may include an interface gasket 245, sized similarly to the cooling base 250, and disposed on the cooling base 250. The thermal interface layer 240 has a thermal conductivity of about 0.2 W / mK to about 4 W / mK. Therefore, the temperature difference across the thermal interface layer 240 can be between 100 degrees Celsius and 300 degrees Celsius, such as 200 degrees Celsius. The thermal interface layer 240 prevents the smearing of the heater in the ceramic ESC 210 by insulating the heat loss from the micro-region 199 to the cooling base 250. The thermal interface layer 240 includes a glass or insulating layer for high temperatures (such as 300 degrees Celsius or higher). The thermal interface layer 240 may have a thickness ranging from about 0.25 mm to about 2.5 mm.

[0042] The cooling base 250 has multiple cooling channels through which cooling fluid circulates during operation. The cooling base 250 has a top surface 252 that contacts the lower surface 244 of the thermal interface layer 240. Both the cooling base 250 and the thermal interface layer 240 have an outer diameter 255. The outer diameter 255 is a distance 271 shorter than the outer perimeter 201 of the ESC 210. The cooling base 250 has a convection cooling chamber 950. The cooling base 250 has multiple cooling channels through which cooling fluid flows to regulate the temperature of the cooling base 250. The cooling base 250 regulates the temperature of the substrate support assembly 200 by allowing coolant to flow within it, thereby maintaining the temperature of the cooling base 250 by removing heat along with the cooling fluid. The convection cooling chamber 950 is maintained at a similar temperature, such as approximately 60°C, by the coolant flowing through the cooling base 250. In addition, the cooling base 250 prevents the high temperature generated by the heater 204 in the ceramic ESC 210 from causing thermal damage to the facility plate and lower components of the substrate support assembly 200.

[0043] A mounting plate 260 is disposed below a cooling base 250. The mounting plate 260 has an upper top surface 263, a lower top surface 265, and a bottom surface 283. A protrusion 277 extends to the upper top surface 263. The upper top surface 263 abuts against a ceramic plate 230. The mounting plate 260 has a sealing groove 269 disposed in the upper top surface 263 therein. Alternatively, the sealing groove 269 may be formed on the bottom surface 234 of the ceramic plate 230. A gasket 294 is disposed in the sealing groove 269 for an airtight seal between the ceramic plate 230 and the mounting plate 260. The protrusion 277 has an inner diameter 261. The inner diameter 261 extends from the lower top surface 265 to the upper top surface 263. The cooling base 250 is disposed on the lower top surface 265 and has an outer diameter 255 extending to the inner diameter 261 of the mounting plate 260.

[0044] Facility plate 260 is formed of aluminum, aluminum alloy, or other suitable material. Electrical connections supplying power to the various components of the electrodes, heaters, and substrate support assembly 200 extend through facility plate 260. Facility plate 260 has through-holes 268 extending therethrough. Through-holes 268 are aligned with holes 238 in ceramic plate 230. Recesses 267 are formed on the bottom surface 264 of facility plate 260 and are aligned with through-holes 268.

[0045] Insert 284 is disposed in cavity 235 of ceramic plate 230. Fastener 281 has head 282. Fastener 281 is configured to extend through through hole 268 into insert 284 in cavity 235. Head 282 of fastener 281 fits into recess 267 of facility plate 260 and abuts through hole 268 without extending in through hole 268. Insert 284 is configured to receive fastener 281 to secure ceramic plate 230 to facility plate 260. Insert 284 may be formed of a conductive material, such as molybdenum, stainless steel, aluminum, or other suitable material. Insert 284 contacts flap 221 of metal connector 220. In this way, when metal connector 220 is used as an electrode, fastener 281 formed of conductive material can provide RF connection to metal connector 220. In other embodiments, ceramic plate 230 is metallized by coating or other techniques. The metallized ceramic plate 230 can be used as an electrode, wherein the fastener 281 forms an RF connection for powering the ceramic plate 230.

[0046] Microzone connector 910 is coupled to auxiliary heater 140 in ESC 210. Microzone connector 910 provides power and controls each individual auxiliary heater 140 to control the heat output in each microzone 199. Microzone connector 910 extends from auxiliary heater 140 at a first end 911 to a convection cooling chamber 950 at a second end 912 of microzone connector 910. The temperature of convection cooling chamber 950 can be maintained at approximately 60°C to provide cooling to components placed therein. The temperature of the first end 911 of microzone connector 910 can be 300°C or higher. The temperature of the second end 912 of microzone connector 910 can be approximately 60°C. Therefore, microzone connector 910 can experience a temperature drop of more than 200°C from the first end 911 to the second end 912 of microzone connector 910.

[0047] Figure 3 This is a schematic partial side view of a substrate support assembly 300 according to another example. The substrate support assembly 300 can be used instead of the substrate support assembly 126 in the aforementioned processing chamber 100. The substrate support assembly 300 is formed by a stack of layers including a ceramic ESC 310, an insulating bonding member 320, a bonding layer 340, and a cooling base 350. Although here... Figure 3 In the diagram, the substrate support assembly 300 is shown as a separate assembly, i.e., the insulating joint 320 is shown separated from the bonding layer 340. However, it should be understood that in practice, the insulating joint 320 and the bonding layer 340 are in contact with each other. Figure 3 The embodiments provide a simple stacking design that can operate at high temperatures.

[0048] The ceramic ESC 310 is configured to operate at temperatures up to and exceeding 300 degrees Celsius. The substrate support assembly 300 utilizes insulating joints 320 to reduce the temperature distribution between the ceramic ESC 310 and the cooling base 350, while preventing warping, bending, or other undesirable thermally induced movements in the layer stack forming the substrate support assembly 300.

[0049] The ceramic ESC 310 has a substrate support surface 312 and a lower surface 314. The ceramic ESC 310 has a body formed of a ceramic material such as alumina or other suitable material. The ceramic ESC 310 has one or more electrodes 302 and a plurality of heaters 304 disposed within the body. The electrodes 302 are configured to adsorb the substrate onto the substrate support surface 312. The plurality of heaters 304 may include a main heater and auxiliary heaters for generating multiple zones to discretely heat the substrate support surface 312, and thus discretely heat the substrate supported on the substrate support surface 312.

[0050] The insulating joint 320 has a top surface 322 and a bottom surface 324. The top surface 322 is disposed abutting against the top surface 322 of the ESC 310. The bottom surface 324 is disposed abutting against the bonding layer 340. The insulating joint 320 may include a metal having a thermal conductivity of about 0.2 W / mK to about 4 W / mK on its top or bottom. Therefore, the temperature difference across the insulating joint 320 may be between about 150 degrees Celsius and about 260 degrees Celsius, such as about 200 degrees Celsius. The insulating joint 320 includes a glass or insulating layer for high temperatures (such as 300 degrees Celsius or higher). The insulating joint 320 may be formed of SiO2, NGO, or other suitable materials. The insulating joint 320 may have a thickness ranging from about 0.25 mm to about 2.5 mm.

[0051] The bonding layer 340 has an upper surface 342 and a lower surface 344. The upper surface 342 contacts the bottom surface 324 of the insulating bonding member 320. The lower surface 344 is disposed on the cooling base 350. The bonding layer 340 may be formed of silicone or other suitable materials suitable for operation at temperatures of about 200 degrees Celsius. The bonding layer 340 has a thermal conductivity of about 0.2 W / mK to about 1.5 W / mK, such as about 0.9 W / mK. The bonding layer 340 may have a temperature drop of about 200 degrees Celsius from the upper surface 342 to the lower surface 344. The bonding layer 340 is a low-temperature bonding member with a thickness between about 0.1 mm and about 1.0 mm, such as about 0.3 mm. The bonding layer 340 further insulates the auxiliary heater 140 from the cooling base 350, thereby helping to prevent the smearing of the heater micro-area effect in the ceramic ESC 310.

[0052] The cooling base 350 has multiple cooling channels through which cooling fluid flows. The cooling base 350 is formed of aluminum or other suitable metals or metal alloys. The cooling base 350 has a top surface 352 and a bottom surface. The top surface 352 of the cooling base 350 contacts the bonding layer 340. The cooling base 350 is provided to regulate the temperature of the substrate support assembly 300. Additionally, the cooling base 350 prevents thermal damage to the facility board and the lower components of the substrate support assembly 300 caused by the high temperatures generated by the heater 304 in the ceramic ESC 310. Furthermore, in some examples, the cooling base 350 can be used as an RF electrode and coupled to a power supply for powering the RF electrode.

[0053] The insulating joint 320 does not extend the entire length of the cooling base 350. A first gap 370 extends between the outer edge of the insulating joint 320 and the outer periphery of the ceramic ESC 310. Similarly, the bonding layer 340 does not extend the entire length of the cooling base 350. A second gap 372 extends between the outer edge of the bonding layer 340 and the outer periphery of the cooling base 350. The first gap 370 and the second gap 372 can be substantially similar in size, such that a seal 392 (such as an O-ring) can be fitted therein when the bonding layer 340 and the insulating joint 320 are placed together to form the substrate support assembly 127. The seal 392 disposed between the ceramic ESC 310 and the cooling base 350 protects the bonding layer 340 and the insulating joint 320 from exposure to plasma and chemicals present in the processing chamber environment, thereby extending the lifespan of the bonding layer 340 and the insulating joint 320.

[0054] Figure 4 This is a schematic partial side view of a substrate support assembly 400 according to yet another example. The substrate support assembly 400 can be used instead of the substrate support assembly 126 in the aforementioned processing chamber 100. The substrate support assembly 400 is formed by a stack of layers including a ceramic ESC 210, a metal bonding member 220, a ceramic plate 230, a thermal interface layer 440, a cooling base 450, and a facility plate 460. The ceramic ESC 210, the metal bonding member 220, and the ceramic plate 230 can be substantially similar to those described above for... Figure 2 The ceramic ESC is described. Additionally, considering a heater configuration in which the ceramic plate 230 is divided into a first ceramic plate 230A and a second ceramic plate 230B in the example, the thermal interface layer 440 may include the interface pad 245 described above for the thermal interface layer 240. The substrate support assembly 400 utilizes the thermal interface layer 440 to reduce heat transfer between the ESC 210 and the cooling base 450, while preventing warping, bending, or other undesirable thermally induced movement in the layer stack forming the substrate support assembly 400. The thermal interface layer 440 also prevents the cooling base 450 from applying discrete temperature micro-regions 199 within the ESC 210.

[0055] The thermal interface layer 440 has an upper surface 442 and a lower surface 444. The upper surface 442 contacts the bottom surface 434 of the ceramic plate 230. The lower surface 444 is sized similarly to the cooling base 450 and is disposed on the cooling base 450. The thermal interface layer 440 may be formed of a high-temperature polymer such as polyimide or other suitable materials. The thermal interface layer 440 prevents the smearing of the heater in the ceramic ESC 210 by insulating the heat loss from the micro-region 199 to the cooling base 250. The thermal interface layer 440 may have a thickness ranging from about 0.25 mm to about 2.5 mm.

[0056] The thermal interface layer 440 does not extend the entire length of the ceramic plate 230 or the cooling base 450. Similar to gap 270, the outer edge of the thermal interface layer 440 is spaced apart from the outer periphery of the ceramic plate 230 and the cooling base 450. Gap 470 is sized to accommodate a gasket 494, or such as an O-ring. Seal 492 forms an hermetically tight seal between the ceramic plate 230 and the cooling base 450. Gasket 294 protects the thermal interface layer 440 from exposure to plasma and chemicals present in the processing chamber environment.

[0057] The cooling base 450 has multiple cooling channels through which cooling fluid circulates during operation. The cooling base 450 has a top surface 452 that contacts the lower surface 444 of the thermal interface layer 240. The cooling base 450 has multiple cooling channels through which cooling fluid flows to regulate the temperature of the cooling base 450. The cooling base 450 regulates the temperature of the substrate support assembly 400 by allowing coolant to flow therein, thereby maintaining the temperature of the cooling base 450 by removing heat along with the cooling fluid. Additionally, the cooling base 450 prevents thermal damage to the facility plate 460 and lower components of the substrate support assembly 400 caused by the high temperatures generated by the heater 204 in the ceramic ESC 210.

[0058] The cooling base 450 has a hole 458 and a first through hole 451. The hole 458 may be a threaded blind hole or another type of hole with a fastener such as a nut disposed therein. The first through hole 451 aligns with a hole 238 in the ceramic plate 230. A fastener 498 is configured to extend through the first through hole 451 into an insert 284 in a cavity 235 of the ceramic plate 230. The fastener 498 secures the ceramic plate 230 to the cooling base 450. The insert 284 is formed of a conductive material such as molybdenum, aluminum, or other suitable material and contacts a fin 221 of a metal connector 220. When the metal connector 220 is an electrode, the fastener 498 provides a conductive RF connection to the metal connector 220 from a power lead 479 disposed through the facility plate 460.

[0059] The cooling base 450 also has the convection cooling chamber 950 described above for the cooling base 250. The micro-area connector 910, coupled to the auxiliary heater 140 in the ESC 210, extends into the convection cooling chamber 950 in the same manner as described above, and has a temperature drop of approximately 200°C from the first end to the second end.

[0060] Facility plate 460 is disposed below cooling base 450. Facility plate 460 has an upper surface 462 and a lower surface 464. Upper surface 462 is disposed abutting against cooling base 250. Facility plate 460 has a sealing groove 469 disposed in upper surface 462. Alternatively, sealing groove 469 may be formed on bottom surface 454 of cooling base 450. Gasket 494 is disposed in sealing groove 469 for hermetic sealing between cooling base 450 and facility plate 460. Facility plate 460 is formed of aluminum, aluminum alloy or other suitable material. Electrical connections supplying power to the various components of electrodes, heaters and substrate support assembly 200 extend through facility plate 460.

[0061] Facility plate 460 has a through hole 468 extending therethrough. The through hole 468 aligns with a hole 458 in the cooling base 450. A notch 467 is formed on the lower surface 464 of facility plate 460 and aligns with the through hole 468. Fastener 496 has a head 482. The head 482 of fastener 496 is fitted into and abuts against the facility plate 460. The hole 458 in the cooling base 450 is configured to receive a fastener 281. For example, the hole 458 may be threaded. Fastener 281 secures the cooling base 450 to facility plate 460.

[0062] In the various embodiments described above, the substrate support assembly has an electrostatic chuck with 150 or more heating zones (microzones). The ESC is placed on a cooling base, and one or more layers are present between them to prevent a firm bond with the cooling base without bending the ESC. One or more layers include an insulating layer that prevents heat leakage from the ESC into the cooling base. Additionally, the insulating layer is capable of operating at high temperatures, such as exceeding approximately 300 degrees Celsius. The insulating layer prevents smearing between the multiple heater microzones (such as 150 or more microzones on the ESC) and thus allows for discrete control of the temperature of each microzone.

[0063] While the foregoing describes embodiments of the present invention, other and further embodiments of the present invention may be devised without departing from the basic scope of the present invention, and the scope of the present invention is defined by the appended claims.

Claims

1. A substrate support assembly, comprising: A first ceramic plate having a workpiece support surface and a bottom surface, and having a plurality of auxiliary heaters, each auxiliary heater forming a plurality of micro-regions; A second ceramic plate, the second ceramic plate having an upper surface and a lower surface; A first metal bonding layer is disposed between the bottom surface of the first ceramic plate and the upper surface of the second ceramic plate; A third ceramic plate having a top portion and a bottom portion, and a main heater; as well as A second metal bonding layer is disposed between the lower surface of the second ceramic plate and the top portion of the third ceramic plate. The coefficient of thermal expansion of the first ceramic plate is less than that of the second and third ceramic plates. The first ceramic plate is an electrostatic chuck.

2. The substrate support assembly of claim 1, wherein the main heater has four separately controlled zones.

3. The substrate support assembly of claim 2, wherein the second ceramic plate further comprises: A cavity having an insert disposed therein, wherein the insert is configured to receive a fastener.

4. The substrate support assembly as claimed in claim 1, further comprising: A cooling base having an upper portion, the upper portion of which is disposed below the third ceramic plate; as well as An interface gasket is disposed between the third ceramic plate and the cooling base, wherein the interface gasket allows a temperature difference of up to 300 degrees Celsius between the third ceramic plate and the cooling base without causing the third ceramic plate to bend or crack.

5. The substrate support assembly of claim 4, wherein the substrate support assembly is configured to have a maximum temperature difference of up to 300°C between the third ceramic plate and the cooling base.

6. The substrate support assembly of claim 4, wherein the cooling base is an RF electrode.

7. The substrate support assembly of claim 4, wherein the interface pad is made of one or more of graphite sheets, polyimide, metal, silicone resin or fluoropolymer.

8. The substrate support assembly of claim 4, wherein the interface pad has a thickness in the range of 0.1 mm to 2 mm.

9. The substrate support assembly of claim 1, wherein the first metal connector is an RF electrode and the metal connector is coupled to an RF power source.

10. The substrate support assembly of claim 1, wherein the first metal bonding layer has a thickness in the range of 0.025 mm to 2 mm.

11. The substrate support assembly of claim 9, wherein the first metal bonding layer and the second metal bonding layer each have a thickness of 0.1 mm to 0.6 mm.

12. The substrate support assembly of claim 1, wherein at least 150 separate auxiliary heaters are present, and the auxiliary heaters are at most 2 mm away from the outer edge of the first ceramic plate.

13. The substrate support assembly of claim 1, wherein the auxiliary heater in the first ceramic plate is less than 3 mm away from the surface of the workpiece.

14. The substrate support assembly of claim 1, wherein the main heater has one or more main heater regions, and the auxiliary heater forms a plurality of microregions, wherein the number of microregions is an order of magnitude greater than the number of main heater regions, and each individual microregion is in one and only one main heater region.

15. A processing chamber, comprising: The main body has walls and a cover defining an internal processing area; A substrate support assembly is disposed in the internal processing area, and the substrate support assembly includes: A first ceramic plate having a workpiece support surface and a bottom surface, and having a plurality of auxiliary heaters, each auxiliary heater forming a plurality of micro-regions; A second ceramic plate, the second ceramic plate having an upper surface and a lower surface; A first metal bonding layer is disposed between the bottom surface of the first ceramic plate and the upper surface of the second ceramic plate; A third ceramic plate, the third ceramic plate having a top portion and a bottom portion, the third ceramic plate having a main heater; and A second metal bonding layer is disposed between the lower surface of the second ceramic plate and the top portion of the third ceramic plate. The coefficient of thermal expansion of the first ceramic plate is less than that of the second and third ceramic plates. The first ceramic plate is an electrostatic chuck.

16. The processing chamber of claim 15, wherein the main heater has four separately controlled zones.

17. The processing chamber of claim 15, further comprising: A cooling base having an upper portion, the upper portion of which is disposed below the third ceramic plate; as well as An interface gasket is disposed between the third ceramic plate and the cooling base, wherein the interface gasket allows a temperature difference of up to 300 degrees Celsius between the third ceramic plate and the cooling base without causing the third ceramic plate to bend or crack.

18. The processing chamber of claim 17, wherein the substrate support assembly is configured to have a maximum temperature difference of up to 300°C between the third ceramic plate and the cooling base.

19. The processing chamber of claim 17, wherein the auxiliary heater in the first ceramic plate is less than 3 mm away from the surface of the workpiece.

20. The processing chamber of claim 17, wherein the auxiliary heater in the first ceramic plate is less than 2 mm away from the outer edge of the first ceramic plate.

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