Vacuum seal for electrostatic chuck

Abstract

An exemplary substrate support assembly may include an electrostatic chuck body. The body may include a support plate defining a substrate support surface. The body may include a base plate coupled to the support plate. A bottom surface of the base plate may define an annular recess. The body may include a cooling plate coupled to the base plate. The assembly may include a support stem coupled to the body. The assembly may include a heater embedded within the body. The assembly may include one or more electrodes embedded within the body. The assembly may include an annular plate disposed within the annular recess. The annular plate may have a thermal conductivity of less than about 20 W / mK. The assembly may include a vacuum seal element disposed between the annular plate and the cooling plate. The assembly may include a thermal gasket disposed radially inward of the vacuum seal element.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. patent application Ser. No. 17 / 885,367, entitled "VACUUM SEAL FOR ELECTROSTATIC CHUCK," filed Aug. 10, 2022, the entire contents of which are incorporated herein by reference.

[0002]

[0002] The present technology relates to components and apparatus for semiconductor manufacturing. More particularly, the present technology relates to substrate support assemblies and other semiconductor processing equipment. [Background technology]

[0003]

[0003] Integrated circuits are made possible by processes that create intricately patterned layers of material on substrate surfaces. Creating patterned materials on substrates requires controlled methods for forming and removing materials. The temperatures at which these processes occur can directly affect the final product. The temperature of the substrate is often controlled and maintained by the assembly that supports the substrate during processing. An internal heating device generates heat within the support, which can then be conductively transferred to the substrate. Some techniques also utilize the substrate support to generate a substrate-level plasma and electrostatically chuck the substrate to the support. Plasma generated near the substrate can form parasitic plasma in undesirable areas of the chamber as well as cause component bombardment. This condition can also lead to discharges between the substrate support electrodes. Furthermore, using a pedestal for both heat generation and plasma generation can result in interference effects.

[0004]

[0004] Because various operating processes may utilize elevated temperatures, as well as plasma formation at the substrate level, the construction materials of the substrate support may be exposed to temperatures that affect the electrical operation of the assembly. Therefore, there is a need for improved systems and methods that can be used to manufacture high quality devices and structures. These and other needs are addressed by the present technology. Summary of the Invention

[0005] An exemplary substrate support assembly may include an electrostatic chuck body. The chuck body may include a support plate defining a substrate support surface. The chuck body may include a base plate coupled to the support plate opposite the substrate support surface. A bottom surface of the base plate may define an annular recess. The chuck body may include a cooling plate coupled to the bottom surface of the base plate opposite the support plate. The assembly may include a support stem coupled to the electrostatic chuck body. The assembly may include a heater embedded within the electrostatic chuck body. The assembly may include one or more electrodes embedded within the electrostatic chuck body and spaced apart from the heater. The assembly may include an annular plate disposed within the annular recess. The annular plate may have a thermal conductivity of less than about 20 W / mK. The assembly may include a vacuum seal element disposed between the annular plate and the cooling plate. The assembly may include a thermal gasket disposed radially inward of the vacuum seal element.

[0006] In some embodiments, the annular recess may extend through the periphery of the base plate. The annular plate may have a thickness of less than about 2 mm. The annular plate may have a width of about 2 mm to 20 mm. The top surface of the cooling plate may define an annular groove. The vacuum seal element may be seated within the annular groove. The electrostatic chuck body may define a plurality of lift pin apertures. The bottom surface of the base plate may define additional annular recesses around each of the plurality of lift pin apertures. The assembly may include additional annular plates. Each of the additional annular plates may be seated within a respective one of the additional annular recesses. The assembly may include additional vacuum seal elements. Each of the additional vacuum seal elements may be disposed between the cooling plate and a respective one of the additional annular plates. The annular plates may include a fluorine-resistant material. The thermal expansion coefficient of the annular plate may be within about 10% of the thermal expansion coefficient of the base plate. The one or more electrodes may be disposed within the support plate. The heater may be disposed within the base plate.

[0007] Some embodiments of the present technology may include a substrate support assembly that may include an electrostatic chuck body. The chuck body may include a support plate defining a substrate support surface. The chuck body may include a base plate coupled to the support plate opposite the substrate support surface. A bottom surface of the base plate may define an annular recess. The chuck body may include a cooling plate coupled to the bottom surface of the base plate opposite the support plate. The assembly may include a heater embedded within the electrostatic chuck body. The assembly may include one or more electrodes embedded within the electrostatic chuck body and spaced apart from the heater. The assembly may include an annular plate disposed within the annular recess. The annular plate may have a thermal conductivity of less than about 20 W / mK. The assembly may include a vacuum seal element disposed between the annular plate and the cooling plate.

[0008] In some embodiments, the annular plate may have a thermal conductivity of less than about 5 W / mK. The assembly may include a thermal gasket disposed radially inward of the vacuum seal element. The thermal gasket may have a thickness of less than about 2 mm. The vacuum seal element may include a perfluoropolymer. The electrostatic chuck body may define a backside gas channel extending through the thickness of the electrostatic chuck body and through the substrate support surface. The bottom surface of the base plate may define an additional annular recess around the backside gas channel. The assembly may include an additional annular plate seated in the additional annular recess. The assembly may include an additional vacuum seal element disposed between the cooling plate and the backside gas channel. The annular channel may be disposed radially inward of a periphery of the base plate. The annular plate may have a thermal expansion coefficient of about 4.7 to 5.

[0009] Some embodiments of the present technology may include a substrate support assembly that may include one or more top plates. The top plate of the one or more plates may define a substrate support surface. A bottom surface of a bottom plate of the one or more plates may define an annular recess. The assembly may include a cooling plate coupled to the bottom surface of the bottom plate. The assembly may include a heater embedded within one of the one or more plates. The assembly may include an electrode embedded within one of the one or more plates and spaced apart from the heater. The assembly may include an annular plate disposed within the annular recess. The annular plate may have a thermal conductivity of less than about 20 W / mK. The assembly may include a vacuum seal element disposed between the annular plate and the cooling plate. In some embodiments, the bottom plate and the top plate may be the same plate.

[0010] The above technology may provide numerous advantages over conventional systems and techniques. For example, embodiments of the present technology may provide an electrostatic chuck mechanism that can operate at high temperatures without degrading the seal mechanism that seals the interior of the chuck mechanism from the vacuum of a processing chamber. The chuck mechanism may allow the use of standard seal elements even under high temperature processing conditions, reducing the cost and complexity of the chuck mechanism. These and other embodiments, along with their many advantages and features, are described in more detail below in conjunction with the description and accompanying figures.

[0011] A further understanding of the nature and advantages of the disclosed technology may be realized by reference to the remaining portions of the specification and the drawings. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 illustrates a top view of an exemplary processing system in accordance with some embodiments of the present technique. [Figure 2] 1 is a schematic cross-sectional view of an exemplary processing system according to some embodiments of the present technique; [Figure 3] 1 is a schematic partial cross-sectional view of an exemplary processing chamber according to some embodiments of the present technique; [Figure 4] 1 is a schematic partial cross-sectional view of an exemplary substrate support assembly according to some embodiments of the present technique; [Figure 4A] 5 is a top view of the substrate support assembly of FIG. 4 in accordance with some embodiments of the present technology. [Figure 4B] 5 is a bottom view of the portion of the substrate support assembly of FIG. 4 above the cooling plate in accordance with some embodiments of the present technique. DETAILED DESCRIPTION OF THE INVENTION

[0013]

[0018] Some figures are included as schematic diagrams. It should be understood that the figures are for illustrative purposes and should not be considered to scale unless the scale is explicitly stated. Furthermore, as schematic diagrams, the figures are provided to aid in understanding and may not include all aspects or information compared to realistic representations and may include exaggerated material for illustrative purposes.

[0014]

[0019] In the accompanying figures, similar components and / or features may be labeled with the same reference label. Furthermore, various components of the same type may be distinguished by following the reference label with a letter that distinguishes between the similar components. When only a first reference label is used herein, the description is applicable to any one of the similar components having the same first reference label, regardless of the letter.

[0015]

[0020] In plasma-enhanced deposition processes, a voltage may be applied to one or more constituent precursors to promote film formation on the substrate. These processes are often performed using a pedestal containing a heater capable of heating and controlling the substrate temperature at the desired process temperature. The plasma is generated by an exothermic reaction, which can generate a large amount of heat. While many processes can be performed at temperatures high enough to overcome the thermal effects from the plasma, the heat from the plasma can affect the process if the process is performed at intermediate temperatures, such as above about 100°C but below about 500°C or lower. This heat, along with the heat from ion bombardment during plasma formation, can exceed the amount of heat that can be dissipated by a conventional pedestal to maintain the set temperature. Such high temperatures can cause failure of sealing elements, such as O-rings and gaskets, used to seal the interior of the chuck mechanism from the vacuum of the processing chamber.

[0016]

[0021] The present technology can incorporate a substrate support assembly that can include components that insulate the sealing elements from the highest temperatures within the chamber. For example, one or more annular plates can be provided within a groove in the base plate of the chuck body. These annular plates can be formed of a material with a lower thermal conductivity than the base plate and can be positioned above and / or otherwise aligned with the sealing elements. This can allow the annular plates to thermally insulate or otherwise shield the sealing elements from the high temperatures of the base plate during processing steps. Such thermal insulation can provide sufficient temperature reduction to allow conventional sealing elements (such as perfluoropolymer O-rings and gaskets) to be utilized in high-temperature processing steps (e.g., where temperatures exceed 350°C) without risk of thermal degradation of the sealing elements.

[0017]

[0022] While the remainder of the disclosure routinely identifies specific deposition processes using the disclosed technology, it will be readily understood that the systems and methods are equally applicable to other deposition, etch, and cleaning chambers and processes that may be performed in the described chambers. Accordingly, the present technology should not be considered limited to use with only these specific deposition processes or chambers. This disclosure describes one possible system and chamber that may include a pedestal according to embodiments of the present technology, before describing additional variations and adjustments to this system according to embodiments of the present technology.

[0018]

[0023] FIG. 1 illustrates a top view of one embodiment of a deposition, etch, bake, and cure chamber processing system 100 according to an embodiment. In the figure, a pair of front-opening unified pods 102 deliver substrates of various sizes that are received by a robot arm 104 and placed in a low-pressure holding area 106 before being placed in one of the substrate processing chambers 108a-f positioned in tandem sections 109a-c. A second robot arm 110 is used to shuttle substrate wafers from the holding area 106 to the substrate processing chambers 108a-f. Each substrate processing chamber 108a-f can be equipped to perform multiple substrate processing steps, including plasma-enhanced chemical vapor deposition, atomic layer deposition, physical vapor deposition, etching, pre-cleaning, degassing, alignment, and the formation of stacks of semiconductor materials as described herein, in addition to other substrate processes including annealing, ashing, and the like.

[0019]

[0024] The substrate processing chambers 108a-f can include one or more system components for depositing, annealing, curing, and / or etching a dielectric or other film on a substrate. In one configuration, two pairs of processing chambers, e.g., 108c-d and 108e-f, can be used to deposit a dielectric material on a substrate, and a third pair of processing chambers, e.g., 108a-b, can be used to etch the deposited dielectric. In another configuration, all three pairs of chambers, e.g., 108a-f, can be configured to deposit a stack of alternating dielectric films on a substrate. Any one or more of the described processes can be performed in separate chambers from the fabrication system shown in different embodiments. It should be understood that additional configurations of deposition, etching, annealing, and curing chambers for dielectric films are contemplated by system 100.

[0020]

[0025] 2 is a schematic cross-sectional view illustrating an exemplary plasma system 200 according to some embodiments of the present technique. The plasma system 200 may illustrate a pair of processing chambers 108 equipped in one or more of the tandem sections 109 described above and may include a substrate support assembly according to embodiments of the present technique. The plasma system 200 may generally include a chamber body 202 having a sidewall 212, a bottom wall 216, and an interior sidewall 201 that defines a pair of processing regions 220A and 220B. Each of the processing regions 220A-220B may be similarly configured and may include identical components.

[0021]

[0026] For example, processing region 220B (components of which may also be included in processing region 220A) may include a pedestal 228 disposed in the processing region through a passageway 222 formed in the bottom wall 216 of plasma system 200. The pedestal 228 may provide a heater adapted to support a substrate 229 on an exposed surface of the pedestal, such as a body portion. The pedestal 228 may include a heating element 232, such as a resistive heating element, capable of heating and controlling the substrate temperature to a desired process temperature. The pedestal 228 may also be heated by a remote heating element, such as a lamp assembly, or any other heating device.

[0022]

[0027] The body of the pedestal 228 may be coupled to the stem 226 by a flange 233. The stem 226 may electrically couple the pedestal 228 to a power outlet or power box 203. The power box 203 may include a drive system that controls the elevation and movement of the pedestal 228 within the processing region 220B. The stem 226 may also include a power interface for supplying power to the pedestal 228. The power box 203 may also include an interface for power and temperature indicators, such as a thermocouple interface. The stem 226 may include a base assembly 238 adapted to detachably couple to the power box 203. A perimeter ring 235 is illustrated above the power box 203. In some embodiments, the perimeter ring 235 may be a shoulder adapted as a mechanical stop or land configured to provide a mechanical interface between the base assembly 238 and the top surface of the power box 203.

[0023]

[0028] A rod 230 may be included through a passage 224 formed in the bottom wall 216 of the processing region 220B and may be utilized to position substrate lift pins 261 disposed through the body of the pedestal 228. The substrate lift pins 261 may selectively space the substrate 229 from the pedestal to facilitate exchange of the substrate 229 by a robot utilized to transfer the substrate 229 into and out of the processing region 220B through the substrate transfer port 260.

[0024]

[0029] A chamber lid 204 may be coupled to the top of the chamber body 202. The lid 204 may house one or more precursor delivery systems 208 coupled thereto. The precursor delivery system 208 may include a precursor inlet passage 240 that may deliver reactant and cleaning precursors into the processing region 220B through a dual channel showerhead 218. The dual channel showerhead 218 may include an annular base plate 248 having a blocker plate 244 disposed intermediate a faceplate 246. A radio frequency (“RF”) source 265 may be coupled to the dual channel showerhead 218, which may provide power to the dual channel showerhead 218 to facilitate generation of a plasma region between the faceplate 246 and the pedestal 228 of the dual channel showerhead 218. In some embodiments, the RF source may be coupled to other portions of the chamber body 202, such as the pedestal 228, to facilitate plasma generation. A dielectric isolator 258 may be disposed between the lid 204 and the dual channel showerhead 218 to prevent conduction of RF power to the lid 204. A shadow ring 206 may be disposed around the periphery of the pedestal 228 to engage the pedestal 228.

[0025]

[0030] Optional cooling channels 247 may be formed in the annular base plate 248 of the gas distribution system 208 to cool the annular base plate 248 during processing. A heat transfer fluid, such as water, ethylene glycol, or gas, may be circulated through the cooling channels 247 to maintain the base plate 248 at a predetermined temperature. A liner assembly 227 may be positioned within the processing region 220B adjacent to the sidewalls 201, 212 of the chamber body 202 to prevent the sidewalls 201, 212 from being exposed to the processing environment within the processing region 220B. The liner assembly 227 may include an ambient pumping cavity 225 that may be coupled to a pumping system 264 configured to exhaust gases and byproducts from the processing region 220B and control the pressure within the processing region 220B. A plurality of exhaust ports 231 may be formed on the liner assembly 227. The exhaust port 231 can be configured to allow the flow of gas from the processing region 220B to the ambient pumping cavity 225 in a manner that facilitates processing within the system 200.

[0026]

[0031] FIG. 3 is a schematic partial cross-sectional view illustrating an exemplary semiconductor processing chamber 300 according to some embodiments of the present technology. FIG. 3 may include one or more components described above with respect to FIG. 2 and may illustrate additional details related to the chamber. Chamber 300 may be used to perform semiconductor processing steps, including the deposition of a stack of dielectric materials, as previously described. Chamber 300 may illustrate a partial view of a processing region of a semiconductor processing system and may not include all of the components, such as the additional lid stack components described above, that are understood to be incorporated into some embodiments of chamber 300.

[0027]

[0032] As previously mentioned, FIG. 3 may illustrate a portion of a processing chamber 300. The chamber 300 may include a showerhead 305 as well as a substrate support assembly 310. The showerhead 305 and substrate support 310, together with chamber sidewalls 315, may define a substrate processing region 320 in which plasma may be generated. The substrate support assembly may include an electrostatic chuck body 325, which may include one or more components embedded within or disposed within the body. Components integrated within the top pack may not be exposed to processing materials in some embodiments and may be retained entirely within the chuck body 325. The electrostatic chuck body 325 may define a substrate support surface 327 and may be characterized by a thickness and a length or diameter depending on the particular geometry of the chuck body. In some embodiments, the chuck body may be elliptical and characterized by one or more radial dimensions from a central axis through the chuck body. It should be understood that the top pack may be any geometry, and when describing a radial dimension, it may define any length from a central location of the chuck body.

[0028]

[0033] The electrostatic chuck body 325 may be coupled to a stem 330, which may support the chuck body and may include channels for delivering and receiving electrical and / or fluid lines that may be coupled to internal components of the chuck body 325. While the chuck body 325 may include associated channels or components to operate as an electrostatic chuck, in some embodiments, the assembly may operate as or include components for a vacuum chuck or any other type of chucking system. The stem 330 may be coupled to the chuck body at a second surface of the chuck body opposite the substrate support surface. In some embodiments, the electrostatic chuck body 325 may be formed from an electrically conductive material (such as a metal such as aluminum or any other material that may be thermally and electrically conductive) and may be coupled to a power source (such as DC power, pulsed DC power, RF bias power, pulsed RF source or bias power, or a combination of these or other power sources) through a filter, which may be an impedance matching circuit, so that the electrostatic chuck body 325 can operate as an electrode. In other embodiments, the top of the electrostatic chuck body 325 may be formed from a dielectric material. In such an embodiment, the electrostatic chuck body 325 may include a separate electrode. For example, the electrostatic chuck body 325 may include a first bipolar electrode 335a that may be embedded within the chuck body proximate to the substrate support surface. The electrode 335a may be electrically coupled to a DC power supply 340a. The power supply 340a may be configured to supply energy or voltage to the conductive chuck electrode 335a, which may operate to form a plasma of a precursor within the processing region 320 of the semiconductor processing chamber 300, but may also sustain other plasma processes. For example, the electrode 335a may also be a chucking mesh that operates as an electrical ground for a capacitive plasma system that includes an RF source 307 electrically coupled to the showerhead 305. For example, the electrode 335a may operate as a ground path for RF power from the RF source 307 and also as an electrical bias for the substrate to provide electrostatic clamping of the substrate to the substrate support surface.The power supply 340a can include a filter, a power supply, and numerous other electrical components configured to provide a chucking voltage.

[0029]

[0034] The electrostatic chuck body can also include a second bipolar electrode 335b, which can be embedded within the chuck body proximate the substrate support surface. The electrode 335b can be electrically coupled to a DC power supply 340b. The power supply 340b can be configured to provide energy or voltage to the conductive chuck electrode 335b. Additionally, electrical components and details regarding bipolar chucks according to some embodiments are described further below, although either design can be implemented in the processing chamber 300. For example, additional plasma-related power supplies or components can be incorporated.

[0030]

[0035] During operation, the substrate may be in at least partial contact with the substrate support surface of the electrostatic chuck body, creating a contact gap that may essentially create a capacitive effect between the surface of the pedestal and the substrate. A voltage may be applied to the contact gap to generate an electrostatic force for chucking. Power supplies 340a and 340b may provide charge transfer from the electrodes to the substrate support surface, where charge may accumulate, creating a charge layer with Coulombic attraction with opposite charges on the substrate, electrostatically holding the substrate against the substrate support surface of the chuck body. This charge transfer may occur due to the finite resistance within the dielectric of the Johnsen-Rahbek type chuck, resulting from current flow through the dielectric material of the chuck body, and may be used in some embodiments of the present technology.

[0031]

[0036] The chuck body 325 may define a recessed region 345 in its substrate support surface, which may provide a recessed pocket in which a substrate may be placed. The recessed region 345 may be formed in an interior region of the top pack and may be configured to receive a substrate for processing. The recessed region 345 may encompass a central region of the electrostatic chuck body, as shown, and may be sized to accommodate a variety of substrate sizes. The substrate may be seated within the recessed region and may be contained by an outer region 347 that may contain the substrate. In some embodiments, the height of the outer region 347 may be such that the substrate is level with or recessed below the surface height of the substrate support surface at the outer region 347. The recessed surface may control edge effects during processing, which, in some embodiments, may improve deposition uniformity across the substrate. In some embodiments, an edge ring may be disposed around the top pack and may at least partially define a recess in which the substrate may be seated. In some embodiments, the surface of the chuck body may be substantially flat, and the edge ring may completely define the recess in which the substrate may be seated.

[0032]

[0037] In some embodiments, the electrostatic chuck body 325 and / or stem 330 may be made of insulating or dielectric materials. For example, oxides, nitrides, carbides, and other materials may be used to form the components. Exemplary materials include ceramics including aluminum oxide, aluminum nitride, silicon carbide, and tungsten carbide, as well as oxides, nitrides, carbides, borides, and titanates of any other metal or transition metal, as well as combinations of these materials with other insulating or dielectric materials. Different grades of ceramic materials may be used to provide composite materials configured to operate over specific temperature ranges; therefore, in some embodiments, different ceramic grades of similar materials may be used for the top pack and stem. In some embodiments, dopants may be incorporated to tailor electrical properties. Exemplary dopant materials may include yttrium, magnesium, silicon, iron, calcium, chromium, sodium, nickel, copper, zinc, or any number of elements known to be incorporated into ceramic or dielectric materials.

[0033]

[0038] The electrostatic chuck body 325 may also include an embedded heater 350 housed within the chuck body. The heater 350 may, in embodiments, include a resistive heater or a fluid heater. In some embodiments, the electrode 335 may operate as a heater, but decoupling these operations allows for more individual control and allows for greater heater coverage while limiting the area of plasma formation. The heater 350 may include a polymer heater bonded or bonded to the chuck body material, but a conductive element may be embedded within the electrostatic chuck body and configured to receive an electric current, such as an AC current, to heat the top pack. The electric current may be routed through the stem 330 via a channel similar to the DC power described above. The heater 350 may be coupled to a power source 365 that may provide an electric current to the resistive heating element to facilitate heating of the associated chuck body and / or substrate. In embodiments, the heater 350 may include multiple heaters, each associated with a zone of the chuck body; thus, an exemplary chuck body may include a similar number of zones as heaters, or a greater number of zones. If present, a chucking mesh electrode 335 may be positioned between the heater 350 and the substrate support surface 327 in some embodiments, and as further described below, in some embodiments, a distance may be maintained between the electrode within the chuck body and the substrate support surface.

[0034]

[0039] The heater 350 may be capable of adjusting the temperature throughout the electrostatic chuck body 325 as well as the substrate residing on the substrate support surface 327. The heater may have an operating temperature range to heat the chuck body and / or substrate to about 100° C. or greater, and the heater may be configured to heat to about 125° C. or greater, about 150° C. or greater, about 175° C. or greater, about 200° C. or greater, about 250° C. or greater, about 300° C. or greater, about 350° C. or greater, about 400° C. or greater, about 450° C. or greater, about 500° C. or greater, about 550° C. or greater, about 600° C. or greater, about 650° C. or greater, about 700° C. or greater, about 750° C. or greater, about 800° C. or greater, about 850° C. or greater, about 900° C. or greater, about 950° C. or greater, about 1000° C. or greater, or greater. The heater may also be configured to operate in any range encompassed between any two of these recited values, or in a smaller range encompassed within either of these ranges, and below any of the recited temperatures.

[0035]

[0040] FIG. 4 is a schematic, partial cross-sectional view of a substrate support assembly 400 according to some embodiments of the present technology. As described above, in some embodiments, the present technology can be used to perform film deposition and curing in a single chamber. The substrate support assembly 400 can be similar to the substrate support assembly 310 and can include any of the features, components, or characteristics of the supports described above, including any associated components or power sources. The substrate support assembly 400 can include a support stem 405, which can be a conductive material. An electrostatic chuck body 425, which can include one or more components embedded or disposed within the body, can be positioned above the support stem 405. Components integrated within the top pack may not be exposed to process materials in some embodiments and may be retained entirely within the chuck body 425. The electrostatic chuck body 425 can define a substrate support surface 427 and can be characterized by a thickness and length or diameter depending on the particular geometry of the chuck body. In some embodiments, the chuck body 425 can be elliptical and characterized by one or more radial dimensions from a central axis through the chuck body. It should be understood that the top puck may be of any shape or size and, when referring to radial dimensions, may define any length from the center location of the chuck body 425 .

[0036]

[0041] The electrostatic chuck body 425 may include multiple plates bonded together. For example, the electrostatic chuck body 425 may be made of an insulating material (e.g., 10 14The components may include one or more top plates 430, which may be formed from a dielectric material (having an electrical resistivity greater than Ω·m). For example, oxides, nitrides, carbides, and other materials may be used to form the components. Exemplary materials include ceramics, including aluminum oxide, aluminum nitride, silicon carbide, tungsten carbide, and any other metal or transition metal oxide, nitride, carbide, boride, or titanate, as well as combinations of these materials with other insulating or dielectric materials. As shown, the top plate 430 may include a support plate 430a and a base plate 430b bonded and / or otherwise coupled to one another. For example, the support plate 430a and the base plate 430b may be bonded to one another using metal bonding techniques such as diffusion bonding, brazing, and / or other bonding techniques. In some embodiments, the bonding technique may include forming a metallic interlayer 442, such as aluminum or another metal, between adjacent top plates 430 to bond the top plates 430 to one another.

[0037]

[0042] The electrostatic chuck body 425 may include a heater 450, such as an AC heating coil. In some embodiments, the heater 450 may be formed from conductive wire, such as wire formed from nickel chromium. An insulating shell may be provided around the heater 450 to prevent short circuits. The heater 450 may be formed from one or more heating elements. By way of example only, the conductive wire may be provided in a spiral or other circuit that expands radially within the electrostatic chuck body 425 to provide relatively uniform heating across the substrate support surface 427. Each heating element of the heater 450 may be coupled to a power source, such as an AC power supply, that delivers AC current to the heater 450 to heat the top pack. The current may be delivered to the heater 450 through one or more rods or wires (not shown) disposed within channels formed in the stem 405 and the electrostatic chuck body 425. In some embodiments, a temperature sensor may extend along the rod or wire. The heater 450 may have an operating temperature range that heats the chuck body 425 and / or the substrate to about 100° C. or greater, and the heater 450 may be configured to heat to about 125° C. or greater, about 150° C. or greater, about 175° C. or greater, about 200° C. or greater, about 250° C. or greater, about 300° C. or greater, or greater. The heater 450 may also be configured to operate in any range encompassed between any two of these recited values, or in any smaller range encompassed within any of these ranges.

[0038]

[0043] The electrostatic chuck body 425 can include one or more electrodes 435 that can be used as chucking electrodes to clamp a substrate to the substrate support surface 427. Each electrode 435 can be electrically coupled to a DC power source that can provide energy or voltage to the electrode 435. The electrode 435 can be a chucking mesh that acts as an electrical ground for a capacitive plasma system that includes an RF source electrically coupled to a showerhead. For example, each electrode 435 can act as a ground path for RF power from the RF source and also as an electrical bias to the substrate to provide electrostatic clamping of the substrate to the substrate support surface.

[0039]

[0044] The heater 450 and each electrode 435 may be embedded within the electrostatic chuck body 425. For example, the electrode 435 may be embedded within the electrostatic chuck body 425 proximate the substrate support surface 427, and the heater 450 may be spaced apart from the electrode 435, e.g., further away from the substrate support surface 427. In some embodiments, the heater 450 and the electrode 435 may be embedded within the same top plate 430 (e.g., support plate 430a), while in other embodiments, the heater 450 and the electrode 435 may be located within separate top plates 430. For example, the electrode 435 may be located within the support plate 430a, and the heater 450 may be located within the base plate 430b.

[0040]

[0045] A top plate (e.g., support plate 430a) of the top plates 430 may define a substrate support surface 427, and one or more top plates 430 (e.g., base plate 430b) may be coupled to the top plate on an opposite side of the substrate support surface 427. In some embodiments, the top plate and the bottom plate may be the same plate, such as when the one or more top plates 430 include only the support plate 430a. The bottom surface 432 of the bottom plate (e.g., support plate 430a in a single top plate embodiment or base plate 430b in a dual top plate embodiment) may define an annular recess 434. The annular recess 434 may extend through the periphery of the bottom plate (e.g., base plate 430b) such that the annular recess 434 includes or is defined by only an upper and an inner wall, as shown here. In other embodiments, the annular recess 434 may be fitted radially inward relative to the periphery of the bottom plate such that the annular recess 434 includes or is defined by an inner wall, an upper wall, and an outer wall.

[0041]

[0046] The annular recess 434 may have a depth of less than about 2 mm. For example, the depth of the annular recess 434 may be about 0.1 mm to 2 mm, about 0.15 mm to 1.75 mm, about 0.2 mm to 1.5 mm, about 0.25 mm to 1.25 mm, about 0.3 mm to 1 mm, about 0.35 mm to 0.75 mm, or about 0.4 mm to 0.5 mm. The width of the annular recess 434 may be about 2 mm to 20 mm, about 3 mm to 18 mm, about 4 mm to 16 mm, about 5 mm to 14 mm, about 6 mm to 12 mm, or about 7 mm to 10 mm.

[0042]

[0047] The annular plate 440 may be disposed within the annular recess 434. For example, the annular plate 440 may seat against one or more surfaces defining the annular recess 434. In some embodiments, the annular plate 440 may have dimensions similar to those of the annular recess 434 such that the annular plate 440 at least substantially fills the annular recess 434. For example, the annular plate 440 may have a thickness of about 0.1 mm to 2 mm, about 0.15 mm to 1.75 mm, about 0.2 mm to 1.5 mm, about 0.25 mm to 1.25 mm, about 0.3 mm to 1 mm, about 0.35 mm to 0.75 mm, or about 0.4 mm to 0.5 mm. While the thickness may allow the bottom surface of the annular plate 440 to be substantially flush with the bottom surface of the bottom plate (e.g., base plate 430b) in some embodiments, in other embodiments, the annular plate 440 may have a thickness that is greater than or less than the depth of the annular recess 434 such that the bottom surface of the annular plate 440 is recessed or protrudes beyond the bottom surface of the bottom plate. The width of the annular plate 440 may be about 2 mm to 20 mm, about 3 mm to 18 mm, about 4 mm to 16 mm, about 5 mm to 14 mm, about 6 mm to 12 mm, or about 7 mm to 10 mm.

[0043]

[0048] The annular plate 440 may be formed from a material having a thermal conductivity of about 20 W / mK or less, about 15 W / mK or less, about 10 W / mK or less, about 5 W / mK or less, about 3 W / mK or less, about 1 W / mK or less, about 0.8 W / mK or less, about 0.6 W / mK or less, about 0.4 W / mK or less, about 0.2 W / mK or less, or less, which may allow the annular plate 440 to insulate the sealing element or other components from the high temperatures of the top plate 430 caused by the heater 450. The annular plate 440 may be formed from a material having a thermal expansion coefficient within about 10%, within about 8%, within about 6%, within about 5%, within about 3%, within about 1%, or less of the coefficient of friction of the bottom plate. In certain embodiments, the bottom plate and the annular plate 440 may each have a coefficient of thermal expansion of about 4.5 to 5.5, about 4.6 to 5.25, or about 4.7 to 5. In some embodiments, the annular plate 440 may be formed from or otherwise include a fluorine-resistant material. Suitable materials for the annular plate 440 may include, but are not limited to, ceramic materials (such as aluminum oxide, aluminum nitride, silicon carbide, tungsten carbide, and any other metal or transition metal oxide, nitride, carbide, boride, or titanate, as well as combinations of these materials with other insulating or dielectric materials), glass, perfluoropolymers, polyamides, and the like. The annular plate 440 may be formed from and / or coated with a fluorine-compatible material (e.g., perfluoropolymers and / or inorganic coatings (e.g., aluminum oxide), etc.).

[0044]

[0049] The electrostatic chuck body 425 may define a number of lift pin apertures 455 that can receive lift pins used to raise a substrate relative to the substrate support surface 427 during a substrate transfer process. The bottom surface 432 of the bottom plate (e.g., the support plate 430a in a single top plate embodiment or the base plate 430b in a dual top plate embodiment) may define an additional annular recess 434a around each lift pin aperture 455, each additional annular recess 434a being similar to the annular recess 434 in some embodiments. For example, in some embodiments, each additional annular recess 434a may have a depth and / or width similar to the annular recess 434, although other dimensions are possible in various embodiments. For example, one or more widths and / or depths of the additional annular recesses 434a may be smaller or larger than that of the annular recess 434. The size can be determined based on the size of each vacuum seal element disposed relative to the annular plate seated in each additional annular recess 434a, with the size of the additional annular plates 434a selected to sufficiently thermally insulate each vacuum seal element from the high temperatures generated by the top plate 430. Each additional recess 434a can receive an additional annular plate 440a, which in some embodiments can be similar to annular plate 440. For example, in some embodiments, each additional annular plate 440a can have a thickness and / or width similar to annular recess 434a, although other dimensions are possible in various embodiments.

[0045]

[0050] As best illustrated in FIG. 4B , the electrostatic chuck body 425 may define one or more backside gas channels 445 that may extend through the thickness of the electrostatic chuck body 425 and enable delivery of one or more gases, such as, but not limited to, a purge gas, to the backside of a substrate positioned on the substrate support surface 427. Each backside gas channel 445 may be coupled to a gas source, such as a gas panel, that delivers gas to the substrate receiving surface via the backside gas channel 445. The bottom surface 432 of the bottom plate (e.g., the support plate 430 a in a single top plate embodiment or the base plate 430 b in a dual top plate embodiment) may define an additional annular recess 434 b around the backside gas channel 445, the additional annular recess 434 b being similar to the annular recess 434 in some embodiments. For example, in some embodiments, each additional annular recess 434 b may have a depth and / or width similar to the annular recess 434, although other dimensions are possible in various embodiments. For example, one or more widths and / or depths of the additional annular recesses 434b may be smaller or larger than that of the annular recess 434. The size may be determined based on the size of the respective vacuum seal element disposed relative to the annular plate seated in each additional annular recess 434b, with the size of the additional annular plate 434b selected to sufficiently thermally insulate the respective vacuum seal element from the high temperatures generated by the top plate 430. Each additional recess 434b may receive an additional annular plate 440b, which in some embodiments may be similar to the annular plate 440. For example, in some embodiments, each additional annular plate 440b may have a thickness and / or width similar to the annular plate 440, although other dimensions are possible in various embodiments.

[0046]

[0051] The top surface 431 of the base plate 430b may define an annular recess 433 that can receive a fastening plate 460, as best illustrated in FIG. 4A. The fastening plate 460 may be formed from a machinable material, such as a metal or polymeric material, that can be machined to include a number of threaded apertures that can receive fasteners used to secure additional components of the electrostatic chuck body 425 to the top plate 430, as described in more detail below. FIG. 4B shows the annular plate 434, the additional annular plate 434a, and the additional annular plate 434b positioned around a portion of the lift pin apertures 455 and backside gas channels 445 defined in the base plate 430b (or other lowermost top plate 430).

[0047]

[0052] The electrostatic chuck body 425 may include a cooling plate 465 coupled to the bottom plate (base plate 430b, as shown) of the top plate 430. The cooling plate 465 may be positioned below the top plate 430 and directly or indirectly coupled to the top ends of the support stems 405. The cooling plate 465 may be formed from a material with high thermal conductivity. High thermal conductivity helps dissipate excess heat from the top plate 430 and reduce thermal shifts that can lead to film non-uniformities on the substrate. The material forming the cooling plate 465 may have a thermal expansion coefficient similar to that of the top plate 430 to prevent damage or deformation of the electrostatic chuck body 425 during temperature fluctuations. For example, the difference in the thermal expansion coefficients of the top plate 430 and the cooling plate 465 can be about 20% or less, about 15% or less, about 10% or less, about 9% or less, about 8% or less, about 7% or less, about 6% or less, about 5% or less, about 4% or less, about 3% or less, about 2% or less, about 1% or less, or less. The cooling plate 465 can be made of a metal such as aluminum, stainless steel, or other material. Alternatively, the cooling plate 465 can be made of a composite ceramic such as SiC or a molybdenum-infiltrated aluminum-silicon alloy to match the thermal expansion coefficient of the top plate 430.

[0048]

[0053] The cooling plate 465 may be coupled to the bottom plate of the top plate 430 using one or more fasteners or the like (e.g., in a dual-plate embodiment, coupled to the base plate 430b opposite the support plate 430a). For example, the bottom surface 466 of the cooling plate 465 may define a number of counterbores 467 that may receive the heads of respective fasteners 468 (e.g., bolts) that may be used to fasten the cooling plate 465 to the bottom plate of the top plate 430. The threads of each fastener 468 may extend through an aperture formed in the thermal gasket 485 and engage with threads formed in the fastener plate 460 to secure the cooling plate 465 to the bottom plate of the top plate 430.

[0049]

[0054] As part of the electrostatic chuck body 425, the cooling plate 465 may define each lift pin aperture 455 and a portion of each backside gas channel 445. The cooling plate 465 may define one or more cooling channels 470. In some embodiments, the upper end of each cooling channel 470 may form an annular or other circuitous pattern around the interior of the cooling plate 465 and be coupled to a cooling fluid source through inlet and outlet channels that extend through the support stem 405. Circulating a cooling fluid, such as water or Galden, through each cooling channel 470 may cool the lower portion of the electrostatic chuck body 425 to help dissipate excess heat generated during the plasma formation process, reducing or eliminating thermal shift and resulting in more uniform film deposition on the substrate. The cooling fluid can be circulated at a temperature of about 125°C or less, about 120°C or less, about 115°C or less, about 110°C or less, about 105°C or less, about 100°C or less, about 95°C or less, about 90°C or less, about 85°C or less, about 80°C or less, about 75°C or less, about 70°C or less, about 65°C or less, about 60°C or less, about 55°C or less, about 50°C or less, or less.

[0050]

[0055] The upper surface 469 of the cooling plate 465 may define one or more annular grooves 475. Each groove 475 may be aligned with a respective one of the annular plates 440. For example, the outermost groove 475a may be aligned with the annular plate 440. If the electrostatic chuck body 425 includes lift pin apertures 455 and / or backside gas channels 445, grooves 475b and 475c may be included, aligned with the additional annular plates 440a and 440b, respectively. Each groove 475 may be sized and shaped to receive a respective vacuum seal element 480. Each vacuum seal element 480 (e.g., an O-ring) may be seated within a respective groove 475 such that the vacuum seal element 480 can be compressed between the cooling plate 465 and a respective one of the annular plates 440 when the cooling plate 465 is secured against the bottom plate of the top plate 430. This may form a vacuum seal, allowing the pressure within the substrate support assembly 400 (often at atmospheric levels) to differ from the chamber environment and / or the pressure within the lift pin apertures 455 (which are often maintained at a vacuum). Additionally, the vacuum seal element 480 may prevent backside gas from flowing from the backside gas channel 445 into the interior of the electrostatic chuck body 425. The presence of the annular plate 440 may help insulate the vacuum seal element 480 from the high temperatures generated at the top plate 430 during processing, allowing for the use of a more conventional vacuum seal element 480. For example, the vacuum seal element 480 may be an O-ring formed from perfluoropolymer (PFP). Alternatively, other types of high-temperature O-rings may be used. In one embodiment, a thermally insulating high-temperature O-ring is used. The O-ring may be a stepped O-ring having a first step at a first thickness and a second step at a second thickness. This may facilitate uniform tightening of fasteners by dramatically increasing the amount of force used to tighten the fasteners after the O-ring is compressed a set amount. Additional grooves and / or O-rings (not shown) may also be placed on the top side of the cooling plate 465 around holes through which cables and / or other components of the substrate support assembly 400 are routed.

[0051]

[0056] The substrate support assembly 400 may include a thermal gasket 485 disposed between at least a portion of the base plate 430b (or other lowermost plate of the top plate 430) and the cooling plate 465. For example, the thermal gasket 485 may be disposed radially inward of the radially outermost vacuum seal element 480a (e.g., seated in groove 475a) and may define multiple apertures to provide access to the fasteners 468, lift pin apertures 455, backside gas channels 445, and / or other features of the electrostatic chuck body 425. In some embodiments, the thermal gasket 485 may be formed from a PFP such as DuPont ECCtreme™, DuPont KALREZ®, or Daikin DUPRA®. Alternatively, the gasket may be a stack of alternating layers of grafoil and polyimide. The thermal gasket 485 may have a thickness of about 0.1 mm to 2 mm, about 0.15 mm to 1.75 mm, about 0.2 mm to 1.5 mm, about 0.25 mm to 1.25 mm, about 0.3 mm to 1 mm, about 0.35 mm to 0.75 mm, or about 0.4 mm to 0.5 mm.

[0052]

[0057] In the foregoing description, for purposes of explanation, numerous details are set forth in order to provide an understanding of various embodiments of the present technology. However, it will be apparent to one skilled in the art that particular embodiments may be practiced without some of these details or with additional details.

[0053]

[0058] Although several embodiments have been disclosed, those skilled in the art will recognize that various modifications, alternative structures, and equivalents may be used without departing from the spirit of the embodiments. Moreover, in order to avoid unnecessarily obscuring the technology, some well-known processes and elements have not been described. Therefore, the above description should not be construed as limiting the scope of the technology.

[0054]

[0059] Where a range of values is provided, it is understood that each intervening value, to the smallest fraction of the unit of the lower limit, between the upper and lower limit of that range is also specifically disclosed, unless the context clearly dictates otherwise. Any narrower range between any stated value or unstated intervening value in a stated range and any other stated or intervening value in that stated range is also included. The upper and lower limits of these smaller ranges may independently be included or excluded, and each range in which either or both limits are included in the smaller ranges is also included within the technology, subject to any specifically excluded limits in the stated range. Where a stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included.

[0055]

[0060] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, a reference to "a heater" includes a plurality of such heaters, a reference to "the rod" includes a reference to one or more rods and equivalents thereof known to those skilled in the art, and so forth.

[0056]

[0061] Also, as used in this specification and the claims that follow, the terms "comprise," "comprising," "contain," "containing," "include," and "including" specify the presence of stated features, integers, components, or steps, but do not exclude the presence or addition of one or more other features, integers, components, steps, operations, or groups.

Claims

1. 1. A substrate support assembly comprising: An electrostatic chuck body, a support plate defining a substrate support surface; a base plate coupled to the support plate opposite the substrate support surface, the bottom surface of the base plate defining an annular recess; a cooling plate coupled to the bottom surface of the base plate opposite the support plate; an electrostatic chuck body including: a support stem coupled to the electrostatic chuck body; a heater embedded in the electrostatic chuck body; one or more electrodes embedded within the electrostatic chuck body and spaced apart from the heater; an annular plate disposed within the annular recess, the annular plate having a thermal conductivity of less than about 20 W / mK; a vacuum sealing element disposed between the annular plate and the cooling plate; a thermal gasket disposed radially inward of the vacuum seal element; A substrate support assembly comprising:

2. the annular recess extends through the periphery of the base plate; The substrate support assembly of claim 1 .

3. the annular plate has a thickness of less than about 2 mm; The substrate support assembly of claim 1 .

4. The annular plate has a width of about 2 mm to 20 mm. The substrate support assembly of claim 1 .

5. an upper surface of the cooling plate defining an annular groove; The vacuum seal element is seated within the annular groove. The substrate support assembly of claim 1 .

6. the electrostatic chuck body defining a plurality of lift pin apertures; the bottom surface of the base plate defines an additional annular recess around each of the plurality of lift pin apertures; the substrate support assembly includes an additional annular plate; each of the additional annular plates is seated within a respective one of the additional annular recesses; the substrate support assembly includes an additional vacuum seal element; each of the additional vacuum sealing elements being disposed between the cooling plate and a respective one of the additional annular plates; The substrate support assembly of claim 1 .

7. the annular plate comprises a fluorine-resistant material; The substrate support assembly of claim 1 .

8. the coefficient of thermal expansion of the annular plate is within about 10% of the coefficient of thermal expansion of the base plate; The substrate support assembly of claim 1 .

9. the one or more electrodes are disposed within the support plate; The heater is disposed within the base plate. The substrate support assembly of claim 1 .

10. 1. A substrate support assembly comprising: An electrostatic chuck body, a support plate defining a substrate support surface; a base plate coupled to the support plate opposite the substrate support surface, the bottom surface of the base plate defining an annular recess; a cooling plate coupled to the bottom surface of the base plate opposite the support plate; an electrostatic chuck body including: a heater embedded in the electrostatic chuck body; one or more electrodes embedded within the electrostatic chuck body and spaced apart from the heater; an annular plate disposed within the annular recess, the annular plate having a thermal conductivity of less than about 20 W / mK; a vacuum sealing element disposed between the annular plate and the cooling plate; A substrate support assembly comprising:

11. the annular plate having a thermal conductivity of less than about 5 W / mK; The substrate support assembly of claim 10.

12. a thermal gasket disposed radially inward of the vacuum seal element; The substrate support assembly of claim 10 further comprising:

13. The thermal gasket has a thickness of less than about 2 mm. The substrate support assembly of claim 12 .

14. the vacuum seal element comprises a perfluoropolymer; The substrate support assembly of claim 10.

15. the electrostatic chuck body defining a backside gas channel extending through a thickness of the electrostatic chuck body and through the substrate support surface; The substrate support assembly of claim 10.

16. the bottom surface of the base plate defines an additional annular recess around the backside gas channel; the substrate support assembly includes an additional annular plate seated within the additional annular recess; the substrate support assembly includes an additional vacuum seal element disposed between a cooling plate and the backside gas channel. The substrate support assembly of claim 15 .

17. the annular channel is disposed radially inward of the periphery of the base plate; The substrate support assembly of claim 10.

18. The annular plate has a coefficient of thermal expansion of about 4.7 to 5. The substrate support assembly of claim 10.

19. 1. A substrate support assembly comprising: one or more top plates, a top plate of the one or more plates defining a substrate support surface; a bottom surface of a bottom plate of the one or more plates defines an annular recess; one or more top plates; a cooling plate coupled to a bottom surface of the bottom plate; a heater embedded within one of the one or more plates; an electrode embedded within one of the one or more plates and spaced apart from the heater; an annular plate disposed within the annular recess, the annular plate having a thermal conductivity of less than about 20 W / mK; a vacuum sealing element disposed between the annular plate and the cooling plate; A substrate support assembly comprising:

20. The bottom plate and the top plate are the same plate.

20. The substrate support assembly of claim 19.

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