Extreme uniform heating of substrate support assemblies

Abstract

Embodiments described herein provide a substrate support assembly that achieves temperature uniformity across a workpiece surface. In one embodiment, a substrate support assembly is provided that includes a body. The body is fabricated from a ceramic. The body has a workpiece support surface and a mounting surface. The workpiece support surface and the adhesive chuck body surface have a flatness of less than 10 microns. A first heater is disposed on a bottom surface outside of the body. An adhesive layer is disposed over the first heater, wherein the adhesive layer is electrically insulating, and a cooling base has a body fabricated from a metal. The cooling body has an upper cooling body surface and a lower cooling body surface, wherein the upper cooling body surface has a flatness of less than about 10 microns.

Description

Technical Field

[0001] The embodiments described herein generally relate to semiconductor manufacturing, and more specifically to temperature-controlled substrate support assemblies and methods of using said substrate support assemblies. Background Technology

[0002] Description of related technologies

[0003] As the feature size of device patterns becomes smaller and smaller, the critical dimension (CD) requirements of these features become increasingly important criteria for stable and repeatable device performance. Due to chamber asymmetries (such as temperature, conductivity, and RF field of the chamber and substrate), it is difficult to achieve permissible CD variations across the substrate processed within the processing chamber.

[0004] In the process of using electrostatic chucks, achieving uniform temperature control across the substrate surface is even more challenging due to the non-uniform structure of the chuck beneath the substrate. For example, some areas of the electrostatic chuck have pores, while other areas have lifting rod holes offset laterally relative to the pores. Other areas have clamping electrodes, while still others have heater electrodes offset laterally relative to the clamping electrodes. Because the structure of the electrostatic chuck can vary laterally and orthogonally, achieving uniform heat transfer between the chuck and the substrate is complex and extremely difficult, resulting in localized hot and cold spots across the chuck surface. This leads to non-uniformity in the processing results along the substrate surface.

[0005] The lateral and directional uniformity of heat transfer between the chuck and the substrate is further complicated by the heat transfer schemes commonly used in conventional substrate supports where electrostatic chucks are mounted. This non-uniformity creates specific problems for controlling the etching rate across the substrate. Specifically, cross-substrate temperature non-uniformity makes it difficult to control selective etching from the center to the edge of the substrate when forming device patterns with small critical dimensions within the substrate.

[0006] Therefore, an improved substrate support assembly is needed. Summary of the Invention

[0007] The embodiments described herein provide a substrate support assembly for achieving temperature uniformity across a workpiece surface. In one embodiment, a substrate support assembly is provided, comprising a body. The body is made of ceramic. The body has a workpiece support surface and a mounting surface. The workpiece support surface and the adhesive suction cup body surface have a flatness of less than about 10 micrometers. At least one first heater is disposed on a bottom surface outside the body. An adhesive layer is disposed on the first heater, wherein the adhesive layer is electrically insulating, and a cooling base has a body made of metal. The cooling body has an upper cooling body surface and a lower cooling body surface, wherein the flatness of the upper cooling body surface is less than about 10 micrometers.

[0008] In another example, a substrate support assembly is provided, comprising an electrostatic chuck, at least one first heater, an insulating layer, and a shaft. The electrostatic chuck includes a chuck body made of ceramic. The chuck body has embedded high-voltage clamping electrodes. The chuck body has a workpiece support surface and an adhesive chuck body surface. The workpiece support surface and the adhesive chuck body surface have a flatness of less than about 10 micrometers. The first heater is disposed on the adhesive chuck body surface outside the chuck body. The insulating layer is disposed on top of the first heater. The first heater has a portion trimmed to achieve a desired resistance higher than adjacent portions of the first heater in order to provide a desired temperature output. The ceramic shaft has leads connected to the clamping electrodes embedded in the electrostatic chuck.

[0009] Other embodiments described herein provide a processing chamber having a substrate support assembly that achieves lateral and directional uniformity across a workpiece surface. The processing chamber has a chamber body having walls, a bottom, and a cover, the walls, bottom, and cover enclosing an internal volume. The substrate support assembly is disposed within the internal volume. The substrate support assembly has an electrostatic chuck having a ceramic body. The body has a workpiece support surface and a mounting surface. The workpiece support surface and the adhesive chuck body surface have a flatness of less than 10 micrometers. A plurality of heaters are disposed on a bottom surface outside the body, wherein the heaters are arranged in multiple zones. An adhesive layer is disposed above the plurality of heaters, wherein the adhesive layer is electrically insulating, and a cooling base has a metal body. The cooling body has an upper cooling body surface and a lower cooling body surface, wherein the flatness of the upper cooling body surface is less than about 10 micrometers.

[0010] In yet another embodiment, a method for controlling the temperature uniformity of a workpiece is provided. The method begins with the following steps: providing power to a primary resistive heater having four or more zones formed on the bottom surface of an ESC; measuring temperature across the substrate using multiple temperature sensors; and controlling the temperature uniformity of the substrate within 1 degree Celsius across the substrate surface. The method further includes selectively etching the substrate disposed on a substrate support assembly. Attached Figure Description

[0011] A more detailed description of the invention, which can be used to understand the features of the invention described above and the invention briefly summarized above, can be obtained by referring to the embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the drawings only show typical embodiments of the invention and should not be considered as limiting the scope of the invention, as the invention allows for other equally effective embodiments.

[0012] 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;

[0013] Figure 2 This is a flowchart of an embodiment of a method 300 for processing a substrate using a substrate support assembly (such as the substrate support assembly described above).

[0014] To facilitate understanding, the same reference numerals have been used wherever possible to designate common elements in the figures. It is anticipated that elements disclosed in one embodiment may be advantageously used in other embodiments without specific description. Detailed Implementation

[0015] The embodiments described herein provide a substrate support assembly that achieves lateral and orientational temperature uniformity of an electrostatic chuck including the substrate support assembly, which in turn allows for lateral and orientational uniformity of the lateral temperature distribution of a substrate processed on the substrate support assembly. Furthermore, the substrate support assembly also enables selective etching. Although the substrate support assembly is described below as being in an etching process chamber, it can be used in other types of plasma processing chambers (such as physical vapor deposition chambers, chemical vapor deposition chambers, ion implantation chambers, etc.) and other systems where orientational adjustment of the lateral temperature distribution is desired.

[0016] In one or more embodiments, the substrate support assembly allows for the correction of critical scale (CD) variations at the substrate edges during vacuum processes (such as etching, deposition, implantation, etc.) by allowing the substrate temperature to be used to compensate for chamber inhomogeneities (such as temperature, conductivity, electric field, plasma density, etc.). Embodiments herein describe an electrostatic chuck (ESC) having a ceramic component and embedded electrodes and one or more heating elements printed on the chuck. The ESC structure is bonded to an aluminum cooling base. This base is thermally isolated from the shaft and integrated components. Temperature is measured using multiple temperature probes, and the temperature of the substrate support assembly is controlled by a closed-loop chamber temperature controller.

[0017] Figure 1 This is a schematic cross-sectional view of an exemplary etching processing chamber 100 having a substrate support assembly 126. The processing chamber can be an etching chamber, a plasma processing chamber, an annealing chamber, a physical vapor deposition chamber, a chemical vapor deposition chamber, and an ion implantation chamber, etc., as well as other processing systems where the ability to control the temperature distribution of the substrate is desired. Independent and localized control of the temperature across discrete regions of the substrate support assembly 126 advantageously enables orientational adjustment of the temperature distribution, adjustment of the temperature distribution from center to edge, and reduction of localized temperature roughness (such as hot spots and cold spots) for controlling the plasma processing rate (such as the etching rate).

[0018] The processing chamber 100 includes a grounded chamber body 102. The chamber body 102 includes a wall 104, a bottom 106, and a cover 108 that enclose the internal volume. A substrate support assembly 126 is disposed in the internal volume 124 and supports the substrate 134 on the substrate support assembly 126 during processing.

[0019] The wall 104 of the processing chamber 100 includes an opening (not shown) through which a substrate 134 is transported by a robot into and out of the internal volume 124. A pumping port is formed in either the wall 104 or the bottom 106 of the chamber body 102 and is fluidly connected to a pumping system (not shown). The pumping system is used to maintain a vacuum environment within the internal volume 124 of the processing chamber 100 while removing processing byproducts.

[0020] Gas panel 112 supplies process gas and / or other gases to the internal volume 124 of processing chamber 100 through one or more inlet ports, said one or more inlet ports forming through at least one of a cover 108 or a wall 104 of chamber body 102. The process gas supplied by gas panel 112 is energized within internal volume 124 to form plasma for processing a substrate 134 disposed on substrate support assembly 126. The process gas is energized by RF power inductively coupled to the process gas from a plasma applicator 120 located outside chamber body 102. Figure 1 In the embodiment depicted, the plasma applicator 120 is coupled to a pair of coaxial coils of the RF power source 116 via a matching circuit 118. In other embodiments, the plasma applicator 120 may be one or more chamber components, such as a nozzle assembly coupled to the RF power source 116 via the matching circuit 118.

[0021] Controller 148 is coupled to processing chamber 100 to control the operation of processing chamber 100 and the processing of substrate 134. Controller 148 can be one of any form of general-purpose data processing system that can be used in an industrial environment to control various subprocessors and subcontrollers. Generally, controller 148 includes a central processing unit (CPU) 172 that communicates with common components such as memory 174 and input / output (I / O) circuitry 176. Software commands executed by the CPU of controller 148 cause the processing chamber to, for example, introduce an etching gas mixture (i.e., processing gas) into internal volume 124, form plasma from the processing gas by applying RF power from plasma applicator 120, and etch material layers on substrate 134.

[0022] The substrate support assembly 126 is removably coupled to the support base 125. The support base 125 includes a base portion mounted to the chamber body 102. The substrate support assembly 126 can be periodically removed from the support base 125 to allow for the refurbishment of one or more components of the substrate support assembly 126.

[0023] The substrate support assembly 126 typically includes at least a substrate support member 132. The substrate support member 132 may be a vacuum chuck, an electrostatic chuck, a base, or other workpiece support surface. Figure 1 In this embodiment, the substrate support 132 is an electrostatic chuck, and will be described below as an electrostatic chuck (ESC) 132. The substrate support assembly 126 also includes a cooling base. The substrate support assembly 126 additionally includes a thermal isolator and a base plate. The electrostatic chuck 132, the cooling base, the thermal isolator, and the base plate are surrounded by an edge ring.

[0024] In one embodiment, the edge ring is formed of a silicon-based material. A gap (not shown) is formed in the edge ring to provide a channel for the delivery of purge gas between the edge ring and the electrostatic chuck 132. An additional space (not shown) is provided between the edge ring and the substrate 134, such that the edge ring is configured to provide purge gas delivered beneath the substrate 134. The purge gas is directed away from the center of the substrate 134 and toward an exhaust device, preventing deposition on the edge ring at the outermost edge of the substrate 134. Unlike conventional ESCs with porous plugs and limited purge gas flow, the gap and additional space provide a large conductive purge gas channel communicating upwards beneath the substrate 134, allowing a high flow rate (up to 15 slm) through 16 orifices when the substrate 134 is annealed on the bar. The purge gas additionally originates from orifices provided in the electrostatic chuck 132. The substrate 134 is lifted on the bar, and the subsequent backflow keeps the electrostatic chuck 132 clean without any byproducts condensing on the surface.

[0025] The base plate is configured to house multiple drive mechanisms for raising and lowering multiple lifting rods. Furthermore, the base plate is configured to house multiple fluid connections from the electrostatic chuck 132 and the cooling base. The base plate is also configured to house multiple electrical connections from the electrostatic chuck 132. Numerous connections may extend externally or internally to the substrate support assembly 126, and the base plate provides interfaces to the respective ends of these connections. The base plate can be formed of any metal.

[0026] The heat insulation unit is positioned between the base plate and the cooling base. The heat insulation unit is formed of a chemically and physically stable thermally insulating material, such as cross-linked polystyrene, polyetheretherketone, alumina (Al₂O₃), or other suitable materials.

[0027] A cooling base is disposed between the heat insulator and the electrostatic chuck 132. The cooling base is coupled to a heat transfer fluid source. The heat transfer fluid source provides a non-conductive heat transfer fluid that circulates through one or more conduits disposed in the cooling base. The fluid flowing through adjacent conduits is isolated to achieve localized control of heat transfer between different regions of the electrostatic chuck 132 and the cooling base, which helps to control the lateral temperature distribution of the substrate 134.

[0028] A fluid distributor is fluidly coupled between the outlet of a heat transfer fluid source and a temperature-controlled cooling base. The fluid distributor operates to control the amount of heat transfer fluid supplied to the conduit. The fluid distributor is located outside the processing chamber 100, within the substrate support assembly 126, within the base, or at other suitable locations.

[0029] The electrostatic chuck 132 has a mounting surface and a workpiece surface opposite to the mounting surface. The electrostatic chuck 132 typically includes clamping electrodes embedded in a dielectric body and one or more primary resistive heaters. The dielectric body is made of a ceramic material, such as Y₂O₃, Er₂O₃, AlN, or Al₂O₃. Alternatively, the dielectric body is made of one or more polymer layers, such as polyimide, polyetheretherketone, polyaryletherketone, etc.

[0030] The clamping electrodes are configured as unipolar or bipolar electrodes, or other suitable arrangements. The clamping electrodes are coupled to a clamping power source via an RF filter, which provides RF or DC power to electrostatically hold the substrate 134 to the workpiece surface of the dielectric body. The RF filter prevents damage to electrical equipment from the RF power used to form plasma within the processing chamber 100 or prevents electrical hazards from arising outside the processing chamber 100.

[0031] The workpiece surface of the electrostatic chuck 132 may include gas channels (not shown) to provide back-side heat transfer gas to the gap space defined between the substrate 134 and the workpiece surface of the electrostatic chuck 132. The electrostatic chuck 132 also includes lifting rod holes to receive lifting rods (neither shown) for raising the substrate 134 above the workpiece surface of the electrostatic chuck 132 to facilitate robotic transfer into and out of the processing chamber 100. This enables low-pressure clamping and positive-pressure back-side control of the substrate disposed on the workpiece surface.

[0032] The electrostatic chuck 132 additionally has one or more primary resistive heaters disposed on the mounting surface. For example, the primary resistive heaters may be equipped with polymer sheets attached to the primary resistive heaters or directly printed on the mounting surface (i.e., between the dielectric body and the cooling base). The primary resistive heaters are provided to raise the temperature of the substrate support assembly 126 to a temperature suitable for chamber processing. The primary resistive heaters are configured to regulate the temperature of the electrostatic chuck 132 within a plurality of laterally separated heating zones defined by the primary resistive heaters. The primary resistive heaters are coupled to a primary heater power source via an RF filter. The primary heater power source provides power to the primary resistive heaters. A controller 148 controls the operation of the primary heater power source, which is generally set to heat the substrate 134 to approximately a predetermined temperature.

[0033] In one embodiment, a single primary resistive heater is used to generate a single heating zone. In other embodiments, multiple primary resistive heaters are used to generate multiple laterally separated heating zones, wherein the controller 148 enables preferential heating of one zone of the primary resistive heater relative to primary resistive heaters located in one or more other zones. For example, the primary resistive heaters are concentrically arranged in multiple four separate concentric heating zones.

[0034] The electrostatic chuck 132 includes one or more temperature sensors (not shown) to provide temperature feedback to the controller 148 for controlling the power applied from the main heater power source to the main resistive heater. The controller 148 can also control the operation of the cooling base. The surface temperature of the substrate 134 in the processing chamber 100 is affected by the exhaust of process gases pumped by pumps, slit valves, plasma, and other factors. Both the cooling base and the main resistive heater contribute to controlling the surface temperature of the substrate 134.

[0035] The substrate support assembly 126 includes portions of an electrostatic chuck (ESC) 132, an adhesive layer, a cooling base, and a heat insulator. The ESC 132 is configured for temperature control in four (or more) zones, with uniformity between the zones ranging from approximately 0.3 degrees Celsius to approximately 0.7 degrees Celsius. The ESC 132 can operate at temperatures between approximately -20 degrees Celsius and less than +200 degrees Celsius for low-temperature processes, and at temperatures greater than approximately +200 degrees Celsius for high-temperature processes. For example, the ESC 132 can operate at temperatures such as between approximately -20 degrees Celsius and approximately 150 degrees Celsius.

[0036] The mounting surface and the workpiece surface are positioned on opposite sides of the body of the ESC 132 and separated by approximately 2 mm to approximately 7 mm. The mounting surface has a flatness between approximately 1 micrometer and approximately 10 micrometers (e.g., approximately 2 micrometers). The mounting surface is substantially flat relative to the workpiece surface. The workpiece surface has a flatness between approximately 1 micrometer and approximately 10 micrometers. The body is formed of a ceramic material, such as alumina or other suitable material.

[0037] The main resistive heaters are disposed on the exterior of the body and on the mounting surface. The main resistive heaters are arranged in concentric zones around the center of ESC 132, wherein heaters in a first zone (not shown) are positioned along a first radius, heaters in a second zone (not shown) are positioned along a second radius greater than the first radius, main resistive heaters in a third zone are positioned along a third radius greater than the second radius, and outer main heaters in a fourth zone are positioned along a fourth radius greater than the third radius. The main resistive heaters are formed on the mounting surface by electroplating, inkjet printing, screen printing, physical vapor deposition, stamping, metal mesh, patterned polyimide flexible circuitry, or other suitable methods. For example, the main resistive heaters are printed onto the mounting surface of the body. In other examples, the main resistive heaters can be deposited on the mounting surface by physical vapor deposition, chemical vapor deposition, using the main resistive heaters as pre-manufactured sheets, or by other suitable methods.

[0038] The main resistive heater is a resistor formed from a film of nickel-chromium alloy, rhenium, tungsten, tantalum, or other suitable materials. The resistor has a resistivity (ρ), where a low ρ indicates a material that readily allows charge to move across the heater resistor. The resistance (R) depends on ρ multiplied by the length of the conductor (I) divided by the cross-sectional area, or simply R = ρ l / A. Platinum has approximately 1.06 × 10⁻⁶ l / A at 20 °C. -7 (Ω) The ρ of tungsten at 20°C is approximately 6.60 × 10⁻⁶ m. -8 (Ω) The ρ of nickel-chromium alloys at 20°C is approximately 1.1 × 10⁻⁶ m. -8 Up to approximately 1.5 × 10 -8 (Ω) Therefore, the resistance and heat output of an individual heater can be changed by altering either the length or the cross-sectional area of ​​the conductor.

[0039] The primary resistance heater has a film thickness or wire thickness configured to provide sufficient heat as current flows along the wires of the primary resistance heater. A reduction in the film thickness of the heater results in an increase in the resistance R of the primary resistance heater and a larger heat output from the primary resistance heater. For example, the film thickness for the primary resistance heater can be selected or modified to a reduced film thickness to control the heat generated in portions of the primary resistance heater after it has been placed on the mounting surface. In this way, the primary resistance heater in each zone can be fine-tuned to provide the desired temperature uniformity across the workpiece surface of ESC 132.

[0040] The resistance of one or more of the main resistance heaters mounted on the ESC 132 mounting surface is adjusted. The main resistance heaters can be tested and further adjusted to more precisely meet the desired temperature distribution control criteria.

[0041] The adhesive layer is an electrically insulating layer. It bonds the ESC 132 to the cooling base. The adhesive layer is applied to the main resistance heater and electrically insulates it from contact with the cooling base and from short-circuiting. The adhesive layer is an adhesive, such as an acrylic adhesive, epoxy resin, silicone adhesive, neoprene adhesive, or other suitable adhesive. The adhesive layer has a heat transfer coefficient selected in the range of 0.1 to 160 W / mK. The adhesive material including the adhesive layer may additionally include at least one heat transfer filler, such as alumina (Al₂O₃), aluminum nitride (AlN), and titanium diboride (TiB₂), etc.

[0042] In one embodiment, the adhesive layer has a thickness between about 0.3 mm and about 2.0 mm (e.g., about 1.0 mm) and a thermal conductivity between about 1.0 W / mK and about 3.0 W / mK (e.g., about 1.0 W / mK). As the thickness of the adhesive layer increases, the power delivered to the main resistive heater decreases. Furthermore, the thickness variation of the adhesive layer can be controlled to precisely set the gap between the ESC 132 and the cooling base. The low thickness variation of the adhesive layer enhances the uniformity of the heat transfer rate through the adhesive layer between the ESC 132 and the cooling base, thus improving the ability to maintain a desired temperature distribution across the workpiece surface of the body of the ESC 132 and advantageously improving the ability to maintain a desired temperature distribution across the substrate disposed on the workpiece surface during processing.

[0043] In one embodiment, a seal (such as an O-ring) is disposed between the ESC 132 and the cooling base. The seal surrounds the adhesive layer and isolates the adhesive layer from the processing area of ​​the processing chamber, thus extending the service life of the adhesive layer while preventing eroded adhesive material from becoming process contaminants.

[0044] The cooling base has a body having a top surface and a bottom surface. The body is formed of a metallic material, such as an aluminum alloy. The top and bottom surfaces define opposite sides of the body and are spaced apart by approximately 10 mm to approximately 32 mm. The top surface is substantially flat relative to the bottom surface. The top surface has a flatness of less than approximately 10 micrometers, such as approximately 1 micrometer or approximately 2 micrometers. The bottom surface has a flatness of less than approximately 10 micrometers. The top surface of the cooling base is in contact with an adhesive layer. The cooling base circulates a cooling fluid (such as a perfluoropolyether fluorinated (PFPE) fluid or water), the cooling fluid being suitable for use at approximately 1000 W / m 2- K and approximately 1400 W / m 2- The effective exchange coefficient between K and K maintains the temperature in the cooling base between approximately 90 degrees Celsius and approximately -20 degrees Celsius.

[0045] The bottom surface contacts the top surface of the insulator. The insulator also has a bottom surface opposite the top surface. The top surface has a flatness of less than approximately 10 micrometers.

[0046] The flatness of each of the ESC 132, the cooling base, and the heat insulator facilitates an assembly with an adhesive thickness variation of less than 20 micrometers (e.g., about 1 micrometer) between each of the ESC 132, the cooling base, and the heat insulator. This gap is achieved while maintaining the surfaces of the ESC 132, the cooling base, and the heat insulator substantially parallel to each other. The substrate support assembly 126 collaboratively achieves greater temperature uniformity across a temperature control range of approximately -20 degrees Celsius to approximately 150 degrees Celsius. The temperature uniformity of the substrate support assembly 126 across the workpiece surface can be maintained within less than 1 degree Celsius. This temperature uniformity advantageously enables selective etching of the substrate.

[0047] Terminals are connected to at least the external main heater for coupling the main resistance heater to the main heater power source. The terminals are connected to the external main heater by brazing, soldering, or other suitable methods. The terminals extend through channels formed in the cooling base in a direction substantially perpendicular to the bottom surface of the cooling base. The location of the terminals directly below the external main heater frees up space at the center of the ESC 132 for gas passage and electrical connection to the clamping electrodes. The heat insulator also includes channels to allow the terminals to extend through the heat insulator to facilitate electrical connection. Other main resistance heaters may also have terminals coupled to the main resistance heater in a similar manner.

[0048] Figure 2 This is a flowchart of one embodiment of a method 300 for processing a substrate using a substrate support assembly (such as substrate support assembly 126 as described above). Method 300 begins at block 302, where power is applied to a main resistive heater having four or more zones formed on the bottom surface of an electrostatic chuck (ESC). As described above, the ESC has ceramic components and embedded electrodes and four or more independent heating elements printed on its underside. The main resistive heater is segmented into zones, which can be independently controlled to allow for lateral and directional adjustment of the lateral temperature distribution of the substrate being processed on the substrate support assembly. Furthermore, the main resistive heater in each segmented zone has material that is selectively removed to fine-tune local resistance and temperature output. Therefore, it is possible to achieve a uniform temperature of less than 1 degree Celsius across the substrate.

[0049] At frame 304, multiple resistance thermometers are used to measure the temperature across the substrate. In one embodiment, a resistance temperature detector (RTD) is used to measure the temperature.

[0050] At frame 306, the temperature uniformity of the substrate is controlled within 1 degree Celsius across the substrate surface. The thermometer provides real-time temperature information of the substrate to the closed-loop chamber temperature controller for controlling the heater and maintaining temperature uniformity across the substrate.

[0051] At frame 308, a substrate disposed on a substrate support assembly is etched. The substrate has an etched layer exposed on the substrate. In one embodiment, the etched layer may be a dielectric material such as a silicon-containing material, such as SiO2, SiN, SiON, SiC, SiOC, SiOCN, SiCN, a-Si. In another embodiment, the etched layer may be a metallic dielectric material, such as AlN, HfO2, AlO3, WN, NiSi, etc. In yet another embodiment, the etched layer may be a metallic material, such as Cu, Al, W, Ni, Co, etc. In each of the embodiments, the etched layer is selectively etched relative to other materials or layers on the substrate.

[0052] In another example of a substrate support assembly, the substrate support assembly includes an electrostatic chuck coupled to a shaft. The shaft may be formed of a ceramic material (such as AlN) or other suitable material.

[0053] The electrostatic chuck is manufactured in a manner largely as described above with reference to electrostatic chuck 132. The electrostatic chuck includes a ceramic body with embedded high-voltage clamping electrodes. The clamping electrodes are positioned near the workpiece surface. One or more primary resistance heaters are disposed on the mounting surface of the ceramic body. The one or more primary resistance heaters can be fitted as described above to adjust their resistance and thus their heat output. In some cases, the primary resistance heaters can be fitted after the shaft is coupled to the ceramic body.

[0054] The center of the ceramic body is prepared to facilitate electrical connection after the body is coupled to the shaft. For example, the center of the ceramic body can be prepared by machining the body after firing. The main resistance heater can be applied, for example by screen printing or film, before or after the center of the shaft is machined to facilitate the electrical connection of leads to the electrodes and the main resistance heater.

[0055] After finishing the main resistance heater, an insulating coating is applied over it. The insulating coating can be a ceramic layer (such as AlN), ceramic, or other insulating tape, such as a blank tape or glass tape. The blank tape is an unfired ceramic tape, such as an AlN tape. In one example where the insulating coating is a glass tape, the glass comprises one or more elements selected from the group consisting of Al, N, O, and Y. The insulating coating may include perforations to allow direct coupling of the shaft end to the mounting surface of the ceramic body. The shaft end can be directly bonded to the mounting surface of the ceramic body by diffusion, high-temperature bonding, brazing, or another suitable method.

[0056] The insulating coating can be replaced by a coating containing one or more of alumina (Al₂O₃), silicon oxide (SiO₂), magnesium oxide (MgO), and yttrium oxide (Y₂O₃) (i.e., ASMY). The insulating coating or ASMY coating is plasma-sprayed onto the main resistance heater to a thickness of approximately 300 µm. It should be understood that other techniques are equally suitable for applying an ASMY coating to the main resistance heater. Both the insulating coating and the ceramic body can be heat-treated. The ASMY insulating coating is heat-treated to induce a dielectric breakdown of approximately 4 kV within the insulating coating.

[0057] In one example, the manufacturing sequence for fabricating a substrate support assembly includes: sintering an AlN ceramic body with embedded high-voltage clamping electrodes; then screen-printing one or more primary resistive heaters onto the bottom of the ceramic body to form single or multiple heating zones; and firing the ceramic body having the primary resistive heaters disposed on the ceramic body. After firing, the primary resistive heaters are trimmed, for example, using a laser to adjust the resistance of the heaters. After trimming, the center of the ceramic body is machined to prepare for electrode brazing to the center. An insulating layer is applied over the trimmed heaters and fired. Subsequently, the shaft is bonded to the ceramic body of the ESC using an AlN-containing tape or glass adhesive tape. The AlN-containing tape or glass adhesive tape can form the insulating layer. The insulating layer can be bonded to the heaters simultaneously with the shaft attachment. After the shaft is attached, the terminals of the high-voltage clamping electrodes are brazed inside the shaft.

[0058] Alternatively, or in addition to the sequence described above, the main resistive heater may be trimmed after the shaft is bonded to the ceramic body of the ESC. The substrate support assembly is then heat-treated to produce the desired breakdown voltage.

[0059] In another embodiment of the substrate support assembly, the substrate support assembly is substantially the same as the substrate support assembly described above, except that the insulating coating extends between the mounting surface of the ceramic body and the end of the shaft so that the shaft is fixed to the lower exposed surface of the insulating coating.

[0060] Advantageously, the substrate support described above is capable of adjusting the temperature in one or more zones to provide temperature uniformity that allows for adjustable etch rates. Furthermore, the ESC clamping allows for various backside pressure setpoints independent of chamber pressure to better adjust temperature control across the wafer. This enables radial adjustment of the etch amount across the wafer from center to edge, thereby adding the ability to adjust yield and chamber performance.

[0061] While the foregoing describes embodiments of the present invention, other and additional 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, the substrate support assembly comprising: An electrostatic chuck has a chuck body made of ceramic, the chuck body having a workpiece support surface and an adhesive chuck body surface, the workpiece support surface and the adhesive chuck body surface having a flatness of less than 10 micrometers; as well as A cooling base having a cooling body made of metal or composite, the cooling body having an upper cooling body surface and a lower cooling body surface, the upper cooling body surface facing the adhesive suction cup body, wherein the upper cooling body surface has a flatness of less than 10 micrometers; At least one first heater, said at least one first heater being disposed on the surface of the adhesive suction cup body outside the suction cup body; as well as An adhesive layer is disposed on the first heater, wherein the adhesive layer is electrically insulating.

2. The substrate support assembly as described in claim 1, further comprising: An edge ring surrounds the electrostatic chuck, the cooling base, and the base plate, wherein the edge ring is configured to guide purified gas to the workpiece mounting surface.

3. The substrate support assembly of claim 1, wherein the adhesive layer has a thickness between 0.3 mm and 2.0 mm and a thermal conductivity between 1.0 W / mK and 3.0 W / mK.

4. The substrate support assembly of claim 3, wherein the thickness variation of the adhesive layer between the electrostatic chuck and the cooling base is less than 20 micrometers.

5. The substrate support assembly of claim 1, wherein the first heater is configured to achieve a desired resistance higher than that of an adjacent portion of the first heater to provide a desired temperature output.

6. A substrate support assembly, the substrate support assembly comprising: An electrostatic chuck, the electrostatic chuck having a chuck body made of ceramic, the chuck body having embedded high-voltage clamping electrodes; The suction cup body has a workpiece support surface and an adhesive suction cup body surface, and the workpiece support surface and the adhesive suction cup body surface have a flatness of less than 10 micrometers. At least one first heater is disposed on the surface of the adhesive suction cup body outside the suction cup body, and the first heater is trimmed to achieve a desired resistance higher than that of the adjacent portion of the first heater in order to provide a desired temperature output; An adhesive layer is disposed on the surfaces of the first heater and the adhesive suction cup body, wherein the adhesive layer is electrically insulating; as well as A ceramic shaft having leads that are connected to the heater and to the clamping electrode embedded in the electrostatic chuck.

7. The substrate support assembly of claim 6, wherein the ceramic shaft is bonded to the insulating layer disposed on the first heater.

8. The substrate support assembly of claim 6, wherein the insulating layer comprises one of a ceramic layer, a ceramic strip, and a glass strip.

9. The substrate support assembly as described in claim 8, further comprising: Multiple heaters are disposed on the surface of the adhesive suction cup body outside the suction cup body, wherein the heaters are arranged in multiple zones; An adhesive layer disposed on the plurality of heaters, wherein the adhesive layer is electrically insulating; A base plate, wherein the base plate is disposed below the cooling base; as well as An edge ring surrounds the electrostatic chuck, the cooling base, and the base plate, wherein the edge ring is configured to guide purified gas to the workpiece mounting surface.

10. The substrate support assembly of claim 9, wherein the flatness of the mounting surface and the upper surface is less than 10 micrometers.

11. The substrate support assembly of claim 9, wherein the adhesive layer has a thickness between 0.3 mm and 2.0 mm, the thickness having a variation of less than 20 micrometers, and the adhesive layer has a thermal conductivity between 1.0 W / mK and 3.0 W / mK.

12. The substrate support assembly of claim 9, wherein at least one of the heaters is modified to achieve a desired resistance higher than that of an adjacent portion of the modified heater in order to provide a desired temperature output.

13. The substrate support assembly of claim 11, wherein the ceramic shaft is bonded to the suction cup body.

14. The substrate support assembly of claim 13, wherein the ceramic shaft is bonded to the insulating layer disposed on the first heater.

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