Electrostatic chuck with ceramic monolithic body

Abstract

To provide an electrostatic chuck for a substrate processing system capable of preventing crack generation due to differences in coefficients of thermal expansion and deterioration in plasma processing environment and a manufacturing method therefor.SOLUTION: An electrostatic chuck for a substrate processing system includes a portion 200 including a monolithic body 210 made of ceramic. A plurality of first electrodes 214 are arranged in the monolithic body adjacent to a top surface 212 of the monolithic body to selectively receive a chucking signal. A gas channel 234 is formed in the monolithic body to supply back side gas to the top surface. Coolant channels 228 are formed in the monolithic body to receive fluid and control a temperature of the monolithic body.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 62 / 804,465, filed February 12, 2019. The entire disclosures of the above-referenced applications are incorporated herein by reference.

[0002] The present disclosure relates to substrate processing systems, and more particularly to electrostatic chucks with ceramic monolithic bodies for substrate processing systems. [Background technology]

[0003] The background description provided herein is intended to present the contents of the present disclosure generally. Work by the presently named inventors within the scope of what is described in this Background section, as well as aspects of the description that may not otherwise be considered prior art at the time of filing, are not admitted, expressly or impliedly, as prior art against the present disclosure.

[0004] Substrate processing systems are used to process substrates, such as semiconductor wafers. Exemplary processes performed on the substrate include, but are not limited to, deposition, etching, cleaning, and other types of processes. The substrate is placed on a substrate support, such as an electrostatic chuck (ESC), in a processing chamber. During processing, a gas mixture is introduced into the processing chamber, and a plasma may be used to initiate a chemical reaction. Summary of the Invention

[0005] An electrostatic chuck for a substrate processing system includes a ceramic monolithic body. A plurality of first electrodes are disposed on the monolithic body adjacent a top surface of the monolithic body and configured to selectively receive a chucking signal. A gas channel is formed in the monolithic body and configured to supply a backside gas to the top surface. A plurality of coolant channels are formed in the monolithic body and configured to receive a fluid to control the temperature of the monolithic body.

[0006] In other features, a monolithic body includes a plurality of ceramic green sheets, the monolithic body including a first portion disposed adjacent to a substrate and a second portion located adjacent to the first portion, the first portion being made of a plurality of first ceramic green sheets having a first quality, and the second portion being made of a plurality of second ceramic green sheets having a second quality lower than the first quality.

[0007] In other features, the second plurality of ceramic green sheets have at least one of increased porosity, decreased purity, increased dielectric constant, or increased loss tangent compared to the first ceramic green sheets. A plurality of first electrodes are disposed between the plurality of coolant channels and the top surface. A plurality of second electrodes are disposed on the monolithic body and configured to receive an RF bias signal. The plurality of second electrodes are disposed between the plurality of coolant channels and the plurality of first electrodes. A porous plug is disposed at at least one of an inlet and an outlet of the gas channel.

[0008] In other features, the monolithic body includes a first portion disposed adjacent to the substrate and a second portion disposed adjacent to the first portion, the second portion being fabricated from a plurality of ceramic green sheets, the first portion being deposited on the second portion and including a plurality of ceramic layers and a conductive layer defining a plurality of first electrodes.

[0009] In other features, the first portion is deposited using a process selected from the group consisting of atomic layer deposition and chemical vapor deposition. The monolithic body further includes a lift pin assembly defining a lift pin cavity and disposed in the lift pin cavity.

[0010] A method for fabricating a monolithic electrostatic chuck includes selecting a plurality of ceramic green sheets for the monolithic electrostatic chuck; cutting a plurality of features into a first selected sheet of the plurality of ceramic green sheets, the plurality of features being selected from the group consisting of gas channels, coolant channels, and lift pin cavities; forming a plurality of electrodes on a second selected sheet of the plurality of ceramic green sheets; aligning and arranging the plurality of ceramic green sheets in a stack; and heating the stack to a predetermined temperature to form the monolithic electrostatic chuck.

[0011] In other features, the predetermined temperature is in the range of 1000°C to 2000°C. The plurality of features include coolant channels, the coolant channels extending through adjacent ones of the plurality of ceramic green sheets. The plurality of features include gas channels, the gas channels extending through adjacent ones of the plurality of ceramic green sheets. The method includes disposing a porous plug material in at least one of an inlet and an outlet of the gas channel before heating the stack.

[0012] In other features, the method includes machining at least one surface of the monolithic electrostatic chuck after heating the stack. The method includes forming a plurality of electrodes on selected sheets of the plurality of ceramic green sheets before heating.

[0013] A method for fabricating a monolithic electrostatic chuck includes providing U ceramic green sheets having a first quality, where U is an integer greater than 1; cutting a plurality of features into selected sheets of the U ceramic green sheets; aligning and arranging the U ceramic green sheets into a first stack; providing L ceramic green sheets having a second quality lower than the first quality, where L is an integer greater than 1; cutting a plurality of features into selected sheets of the L ceramic green sheets; aligning and arranging the L ceramic green sheets into a second stack; placing and aligning the first stack adjacent to the second stack; and heating the first stack and the second stack.

[0014] In other features, the first stack and the second stack are heated to a temperature in a range of 1000° C. to 2000° C. The method includes, before heating the first stack and the second stack, forming a plurality of first electrodes configured to receive a chucking bias on selected sheets of the U ceramic green sheets.

[0015] In other features, the method includes forming a plurality of second electrodes configured to receive an RF bias on selected sheets of the U ceramic green sheets before heating the first stack and the second stack. The L ceramic green sheets have at least one of increased porosity, decreased purity, increased dielectric constant, or increased loss tangent compared to the U ceramic green sheets. Cutting the plurality of features includes forming a plurality of coolant channels in at least one of the U ceramic green sheets and the L ceramic green sheets before heating the first stack and the second stack. Cutting the plurality of features includes forming a plurality of gas channels in at least one of the U ceramic green sheets and the L ceramic green sheets before heating the first stack and the second stack.

[0016] In other features, the method includes disposing a porous plug material in at least one of the inlets and outlets of the plurality of gas channels before heating the first stack and the second stack, and after heating the first stack and the second stack, machining at least one surface of the first stack.

[0017] A method for fabricating a monolithic electrostatic chuck includes selecting a plurality of ceramic green sheets for a lower portion of an electrostatic chuck body, cutting a plurality of features into selected ones of the plurality of ceramic green sheets, aligning and arranging the plurality of ceramic green sheets in a stack, heating the stack to a predetermined temperature, and forming a top portion of the electrostatic chuck body by depositing a plurality of layers on a top surface of the stack, the plurality of layers including ceramic and defining a plurality of electrodes.

[0018] In other features, the predetermined temperature is in the range of 1000°C to 2000°C. A first quality of the ceramic material in the upper portion of the electrostatic chuck body is higher than a second quality of the ceramic material in the lower portion of the electrostatic chuck body. The plurality of ceramic green sheets in the lower portion have at least one of increased porosity, decreased purity, increased dielectric constant, or increased loss tangent compared to the plurality of ceramic green sheets in the upper portion. The plurality of features include coolant channels formed in adjacent ones of the plurality of ceramic green sheets. The plurality of features include gas channels formed in adjacent ones of the ceramic green sheets.

[0019] In other features, the method includes disposing a porous plug material in at least one of the inlets and outlets of the gas channels before heating the stack. The method includes machining at least one surface of the bottom portion after heating the stack and before depositing the top portion. Depositing the multiple layers on the top surface of the stack includes a process selected from the group consisting of atomic layer deposition and chemical vapor deposition. The method includes forming multiple electrodes on selected ones of the ceramic green sheets before heating.

[0020] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. [Brief explanation of the drawings]

[0021] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0022] [Figure 1] FIG. 1 is a functional block diagram of an example substrate processing system incorporating an ESC with a ceramic monolithic body according to the present disclosure.

[0023] [Figure 2] FIG. 2 is a partial cross-sectional side view of an example ESC incorporating coolant channels, backside gas channels, electrodes, and RF terminals according to the present disclosure.

[0024] [Figure 3] FIG. 3 is another partial cross-sectional side view of an example ESC incorporating a gas channel with a porous plug, a sensor, and an electrostatic terminal according to the present disclosure.

[0025] [Figure 4] FIG. 4 is another partial cross-sectional side view of an example ESC with a lift pin assembly according to the present disclosure.

[0026] [Figure 5] FIG. 5 is a plan view of an example ESC with gas channels for distributing backside gas according to the present disclosure.

[0027] [Figure 6] FIG. 6 is a plan view of an example ESC with bifilar coolant channels formed in a ceramic monolithic body according to the present disclosure.

[0028] [Figure 7] FIG. 7 is a plan view of an example ESC with single-filar coolant channels formed in a ceramic monolithic body according to the present disclosure.

[0029] [Figure 8A] FIG. 8A is a cross-sectional side view of an example body stack including ceramic green sheets according to the present disclosure before heating.

[0030] [Figure 8B] FIG. 8B illustrates the body stack of FIG. 8A after heating in accordance with the present disclosure.

[0031] [Figure 9] FIG. 9 is a flowchart of an example method for fabricating an ESC with a monolithic body according to the present disclosure.

[0032] [Figure 10A] FIG. 10A illustrates an example of a body stack according to the present disclosure, including a first stack of ceramic green sheets having a first quality and a second stack of ceramic green sheets having a second quality before heating.

[0033] [Figure 10B] FIG. 10B illustrates the body stack of FIG. 10A after heating in accordance with the present disclosure.

[0034] [Figure 11A]FIG. 11A illustrates an example body stack including a first stack of ceramic green sheets corresponding to the bottom of an ESC before heating according to the present disclosure.

[0035] [Figure 11B] FIG. 11B illustrates the body stack of FIG. 11A after heating in accordance with the present disclosure.

[0036] [Figure 11C] FIG. 11C shows the body stack of FIG. 11B after deposition of an ESC on top according to the present disclosure.

[0037] [Figure 12] FIG. 12 is a flowchart of a method for fabricating an ESC with a ceramic monolithic body according to the present disclosure.

[0038] [Figure 13] FIG. 13 is a flowchart of another method for fabricating an ESC with a ceramic monolithic body according to the present disclosure.

[0039] In the drawings, reference numbers may be reused to refer to similar and / or identical elements. DETAILED DESCRIPTION OF THE INVENTION

[0040] An ESC typically includes a ceramic plate bonded to a base plate by a bonding layer. The base plate is usually made of a metal such as aluminum (Al), titanium (Ti), or other metals. The base plate is often coated with a thin layer of ceramic, such as alumina or other coating. The ceramic coating is typically applied using an electrochemical anodization process, a thermal spray process, or other approaches. The ceramic plate and base plate are bonded to each other by a bonding layer. By way of example only, the bonding layer can include a silicone polymer, an organic polymer binder, an inorganic filler, and / or a soft metallic material. The bonding layer typically requires protection from the plasma processing environment.

[0041] There are many drawbacks associated with this design. For example, the ceramic coating tends to break down when exposed to high voltages, causing electrical arcing within the processing chamber. The base plate and ceramic plate also have different CTEs. The mismatched materials expand and contract at different rates in response to changes in temperature. The expansion and contraction cause misalignment and thermal stresses. The ceramic coating can also crack due to the difference in the coefficient of thermal expansion (CTE) between the base plate and the ceramic coating.

[0042] The base plate also functions as a single RF electrode, a fact that makes it difficult to apply different RF potentials to different regions of the base plate.

[0043] The bonding layer acts as a thermal barrier, which limits heat transfer and leads to high substrate temperatures, especially in high-power applications. The bonding layer undergoes deformation cycles during processing due to the different CTEs of the ceramic plate and base plate. Ultimately, the deformation cycles cause delamination of the bonding layer and failure of the ESC.

[0044] In some examples, ESCs according to the present disclosure are fabricated monolithically (without the use of bonding layers). The ESCs include embedded electrodes for electrostatic chucking, temperature control, RF power delivery, RF shielding, etc. The ESCs also include other integrated components such as temperature sensors, current and / or voltage sensors, porous media gas buffers, embedded gas channels, and / or embedded coolant channels.

[0045] The ESC of the present disclosure solves many of the problems encountered when using prior art ESC designs. Because the body of the ESC is monolithic and ceramic, ceramic coatings are eliminated or have similar CTEs. With little or no CTE mismatch, cracking of the ceramic coating is eliminated. As a result, the operating temperature range of the ESC can be extended.

[0046] Since the base plate is no longer metallic, one or more electrodes are embedded in the body of the ESC, which are controlled using one or more RF potentials to vary the RF bias at different locations on the substrate.

[0047] Because the bonding layer is eliminated, failures caused by erosion and delamination of the bonding layer are eliminated, improving the lifespan and reliability of the ESC.

[0048] Because the ESC body is monolithic and ceramic, differential thermal expansion and contraction across the ESC is minimized. As a result, thermal mismatch and thermal stress are significantly reduced. The elimination of bonding layers increases heat transfer from the substrate to the cooling fluid (e.g., gas or liquid) within the ESC. Improved thermal conduction allows for more efficient heat transfer to and from the coolant channels, allowing for higher power applications.

[0049] In some examples, the body of the ESC is made of a material selected from the group consisting of alumina (Al2O3), aluminum nitride (AlN), silicon carbide (SiC), or other ceramic materials. In some examples, the body of the ESC is coated. In some examples, the coating material is selected from the group consisting of alumina (Al2O3), yttrium oxide (YO3), or zirconium dioxide (ZrO2).

[0050] In some examples, the body of the ESC is made of different grades or qualities of ceramic material in different vertical portions thereof to reduce cost and / or optimize performance. For example, a finer grade of ceramic material may be used in the upper portion of the ESC near the substrate, while a lower grade of ceramic material is used in the lower portion of the ESC to improve purity, dielectric, electrical, or mechanical properties, etc.

[0051] In some examples, the ESC includes embedded electrodes made of a material selected from the group consisting of tungsten (W), platinum (Pt), silver (Ag), palladium (Pd), or other conductive materials. The body of the ESC may include one or more electrodes that are connected together or controlled separately. The electrodes may also be located at different locations on the body.

[0052] 1, there is shown a substrate processing system 100 including an electrostatic chuck (ESC) 101. While FIG. 1 shows a capacitively coupled plasma (CCP) system, the present application is also applicable to other processes, such as transformer coupled plasma (TCP) systems, electron cyclotron resonance (ECR) plasma systems, ion beam etchers (IBE), inductively coupled plasma (ICP) systems, and / or other systems that include a substrate support.

[0053] Although ESC 101 is shown mounted to the bottom of the processing chamber, ESC 101 may also be mounted to the top of the processing chamber, where it can be flipped upside down and can include hardware for holding, clamping, and / or gripping peripheral substrates.

[0054] The substrate processing system 100 includes a processing chamber 104. The processing chamber 104 surrounds the ESC 101 and other components. The processing chamber 104 also contains a radio frequency (RF) plasma. During operation, a substrate 107 is placed on the ESC 101 and electrostatically clamped thereto.

[0055] By way of example only, the showerhead 109 may distribute gases and function as the upper electrode 105. The showerhead 109 may include a stem portion 111 including one end connected to the top surface of the processing chamber 104. The showerhead 109 is generally cylindrical and extends radially outward from the opposite end of the stem portion 111 at a location spaced from the top surface of the processing chamber 104. The surface of the showerhead 190 facing the substrate includes gas through-holes through which process gases flow. Alternatively, the upper electrode 105 may include a conductive plate, and gases may be introduced in another manner. An electrode embedded in the ESC 101 functions as the lower electrode.

[0056] The ESC 101 may include one or more gas channels 115 and / or one or more coolant channels 116. The gas channels 115 supply a backside gas, such as helium (He) or other gas, to the backside of the substrate 107. Fluid flows through the coolant channels 116 in the ESC 101 to control the temperature of the ESC 101.

[0057] An RF generation system 120 outputs an RF voltage to the upper electrode 105 and / or the lower electrode in the ESC 101. One of the upper electrode 105 and the lower electrode may be DC grounded, AC grounded, or at a floating potential. By way of example only, the RF generation system 120 may include one or more RF generators 122 that generate an RF voltage. The output of the RF generator 122 is supplied to the upper electrode 105 and / or the lower electrode by one or more matching and distribution networks 124. By way of example, an RF plasma generator 123, an RF bias generator 125, an RF plasma matching network 127, and an RF bias matching network 129 are shown.

[0058] Gas delivery system 130 includes one or more gas sources 132-1, 132-2, ..., and 132-N (collectively gas source 132), where N is an integer greater than zero. Gas source 132 supplies one or more precursors, etching gases, inert gases, carrier gases, purge gases, and gas mixtures thereof. Vaporized precursors may also be used.

[0059] The gas source 132 is connected to a manifold 140 by valves 134-1, 134-2, ..., and 134-N (collectively valves 134) and mass flow controllers 136-1, 136-2, ..., and 136-N (collectively mass flow controllers 136). The output of the manifold 140 is provided to the processing chamber 104. By way of example only, the output of the manifold 140 may be provided to the showerhead 109.

[0060] The substrate processing system 100 further includes a temperature control system 141 that includes a temperature controller 142. Although shown separate from the system controller 160, the temperature controller 142 may be implemented as part of the system controller 160. The temperature controller 142 controls the temperature and flow rate of the coolant flowing through the coolant channels 116 via a coolant assembly 146. The coolant assembly 146 includes a coolant pump that pumps the coolant from a reservoir to the coolant channels 116. The coolant assembly 146 may also include a heat exchanger that transfers heat out of the coolant. The coolant may be, for example, a liquid coolant.

[0061] A valve 156 and a pump 158 are used to evacuate reactants from the processing chamber 104. A robot 170 delivers substrates onto and removes substrates from the ESC 101. For example, the robot 170 can transfer substrates between the ESC 101 and a load lock 172. A system controller 160 can control the operation of the robot 170 and / or the load lock 172. An ESC power supply 180 selectively provides a clamping signal to cause the electrodes to clamp the substrate 107.

[0062] 2, a portion 200 of the ESC 101 is shown. The ESC 101 has a monolithic body 210. In the illustrated example, the monolithic body 210 includes an electrostatic clamping electrode 214 disposed adjacent a top surface 212 of the ESC 101. The electrostatic clamping electrode 214 receives a clamping signal from the ESC power supply 180 and clamps the substrate 107. The electrostatic clamping electrode 214 can be connected to a terminal (described below) that can be connected to the ESC power supply 180. For example, a conductor can pass through an insulating cavity to provide a connection to the electrostatic clamping electrode 214.

[0063] The monolithic body 210 further includes inner and outer radio frequency (RF) electrodes 218-I and 218-O (collectively RF electrodes 218), respectively. The RF electrodes 218 receive power from terminals 220-I and 220-O (collectively terminals 220), which can be connected to the bias RF matching network 129. The terminals 220 are disposed in insulating cavities 222-I and 222-O that extend from the bottom of the ESC 101 to the RF electrodes 218. The RF electrodes 218 are disposed within a predetermined distance from the top surface of the monolithic body 210. The RF electrodes 218 may be disposed in different patterns across the top surface of the monolithic body 210. One or more of the RF electrodes 218-I may be disposed on an upper portion 221 of the monolithic body 210 that protrudes upward and defines an annular slot. One or more of the RF electrodes 218-O may be disposed near the outer periphery of the monolithic body 210. In some examples, the RF electrodes 218-O may be disposed under an edge ring (not shown) that is located in an annular slot and centered by the portion 221.

[0064] The monolithic body 210 also includes gas channels 234 that receive a backside gas (such as helium) to the backside of the substrate 107. The coolant channels 228 are arranged in one or more planes parallel to the substrate 107. The coolant channels 228 can be bifilar or single-filar.

[0065] Referring now to FIG. 3 , a portion 300 of the ESC 101 is shown. One or more vertical inlets (or outlets) 310 provide fluid to the coolant channels 228. The monolithic body 210 includes vertical gas channels 320 that supply backside gas to the gas channels 234. A porous plug 324 is disposed at one end of the vertical gas channel 320 adjacent the bottom surface of the monolithic body 210. A porous plug 325 is disposed between the gas channel 234 and the top surface of the ESC 101. The porous plugs 324, 325 may be made of porous ceramic and may be fired when the ceramic green sheets that form the monolithic body are fired. In some examples, the porous plugs are omitted or installed after firing of the monolithic body. The porous plugs include small pores to prevent plasma formation in the gas channels and prevent line of sight to the plasma.

[0066] The monolithic body 210 includes a vertical cavity 330 that houses a terminal 332 connected to one end of the electrostatic clamping electrode 214. The monolithic body 210 further includes one or more vertical cavities for temperature sensors. Exemplary temperature sensors 342-1, 342-2, and 342-3 (collectively temperature sensors 342) are disposed in the vertical cavities 340-1, 340-2, and 340-3, respectively, and connected to conductors 344-1, 344-2, and 344-3. The temperature sensors 342 provide temperature output signals to the controllers 142, 160.

[0067] 4, a portion 400 of the ESC 101 is shown. The monolithic body 210 includes a lift pin assembly 420 that includes lift pins 410, lift pin channels 414, and gas channels 434. In some examples, the ESC 101 includes three or more lift pin assemblies.

[0068] 5, the ESC 101 includes gas channels 234 for supplying backside gas to the top surface of the monolithic body. Gas is supplied to the gas channels 234 below the substrate 107. Gas flows from the gas channels 234 through porous plugs 325 (not shown in FIG. 5) at various locations to supply the backside gas below the substrate.

[0069] Referring now to FIG. 6, there is shown a coolant channel layer 600 formed in the monolithic body of the ESC 101. The coolant channel layer 600 includes bifilar coolant channels 602. The coolant channels 602 include an inlet 604 and an outlet 608 located in the center of the coolant channel layer 600. One end of the coolant channels 602 starts near the center and wraps around in a circular coiled pattern until it reaches the periphery. The coolant channels 602 return from the periphery to the center in a coiled pattern.

[0070] Referring now to FIG. 7, there is shown a coolant channel layer 700 formed in the monolithic body of the ESC 101. The coolant channel layer 700 includes coolant channels 702 in a single-filer arrangement. The coolant channels 702 include centrally located inlets 704 and outlets 708 located near the periphery of the coolant channel layer 700 (or vice versa). While exemplary coolant channel arrangements are shown in FIGS. 6-7, other arrangements can be used.

[0071] Referring now to FIGS. 8A and 8B, an ESC body stack 800 can be fabricated from ceramic green sheets. In FIG. 8A, the ESC body stack 800 is shown before heating and includes a stack 802 of ceramic green sheets 806. Features such as holes, cavities (e.g., for gas channels, coolant channels, terminals, lift pins), and electrodes are formed in the ceramic green sheets as needed. More porous ceramic green sheets can be used to define porous plugs in the gas channels. In FIG. 8B, the ESC body stack 800 is shown after heating. Among other advantages, the ESC body stack 800 forms a monolithic body (features not shown) after heating. A monolithic body has improved electrical and thermal properties and does not include or require bonding layers that can cause premature failure.

[0072] Referring now to FIG. 9, a method 900 for fabricating a monolithic body of an ESC is shown. At 910, openings are cut in one or more of the ceramic green sheets to define features of the ESC. In some examples, the features are laser cut into the ceramic green sheets. For example, openings corresponding to gas channels, terminals, porous plugs, sensors, and / or cavities for gas flow are cut into the green sheets. In some examples, a laser is used to score or ablate the top surface of the ceramic green sheets to form gas channels parallel to the plane containing the substrate. In other examples, a laser is used to form gas channels, cavities, or other features across one or more ceramic green sheets that are oriented perpendicular to the plane containing the substrate. In some examples, each of the green sheets has a thickness ranging from 0.5 mm to 2 mm, although other thicknesses can be used.

[0073] At 914, electrodes, such as RF electrodes or electrostatic chucking electrodes, are formed on selected ones of the ceramic green sheets. In some examples, the electrodes are formed by printing metal powder on the ceramic green sheets. At 918, a porous plug material is optionally disposed in one or more features (such as gas channels) of the ceramic green sheets. In some examples, the porous plug material comprises a ceramic green sheet material that is different (e.g., more porous) than the green sheet material used for the ESC body. At 922, the ceramic green sheets are rotationally aligned (to align the features) and placed in contact to form a stack.

[0074] At 924, the stack is heated or fired to form a monolithic ESC body. In some examples, the ESC stack is heated to a temperature ranging from 1000°C to 2000°C. At 926, sensors and terminals are optionally installed. At 928, one or more surfaces of the ESC body are machined as needed. Machining can be used to flatten the surface of the ESC body. As can be appreciated, the order of one or more steps can be changed from the foregoing example.

[0075] 10A and 10B, an ESC body stack 1000 can be fabricated from ceramic green sheets. In some examples, the ceramic green sheets have different qualities depending on their location within the ESC 101. Higher quality ceramic green sheets are used near the substrate, while lower quality ceramic green sheets are used in lower or less critical portions of the ESC 101. In FIG. 10A, the ESC body stack 1000 is shown before heating and includes a first stack 1002 of ceramic green sheets 1006 having a first quality. The ESC body stack 1000 includes a second stack 1004 of ceramic green sheets 1008 having a second quality. In FIG. 10B, the ESC body stack 1000 is shown after heating. Among other advantages, the ESC body stack 1000 forms a monolithic body after heating. A monolithic body has improved electrical and thermal properties and does not include or require bonding layers that can cause premature failure.

[0076] 11A-11C, an ESC body 1100 may be formed by assembling ceramic green sheets that are fired and optionally machined. The top of the monolithic body is then formed by deposition of additional materials, such as ceramic and / or conductive materials (forming electrodes). Vias or holes may be defined to allow placement of sensors, such as temperature sensors, lift pin assemblies, terminals for RF electrodes, gas channels, etc.

[0077] In Figure 11A, the ESC body stack 1100 includes a stack of ceramic green sheets 1106. In Figure 11B, the ESC body stack 1100 is shown after heating. In Figure 11C, the ESC body stack 1100 of Figure 11B is shown after ceramic and conductive materials (e.g., defining electrodes) have been deposited on top of the ESC 101. In some examples, machining is performed on the top surface of the ESC 101 before deposition.

[0078] Referring now to FIG. 12, a method 1200 for fabricating a monolithic body of an ESC is shown. In 1210, L ceramic green sheets having a first quality are selected for the lower portion of the ESC body, where L is an integer greater than 1. In 1214, openings are cut into one or more of the L ceramic green sheets to define features for the lower portion of the ESC. In some examples, the features are laser cut into the ceramic green sheets. For example, openings corresponding to gas channels, terminals, porous plugs, sensors, and / or cavities for gas flow are cut into the green sheets. In some examples, a laser is used to score or ablate the top surfaces of the ceramic green sheets to form gas channels parallel to a plane containing the substrate. In other examples, a laser is used to form gas channels, cavities, or other features oriented perpendicular to a plane containing the substrate across one or more ceramic green sheets. In some examples, each of the green sheets has a thickness ranging from 0.5 mm to 2 mm, although other thicknesses can be used.

[0079] At 1218, U ceramic green sheets having a second quality are selected for the top of the ESC body, where U is an integer greater than 1. In some examples, the second quality is higher than the first quality. For example, the second quality may differ from the first quality in porosity, purity, dielectric constant, loss tangent, or other property.

[0080] At 1222, features are cut into one or more of the U ceramic green sheets to define the tops of the ESCs. At 1224, electrodes, such as RF electrodes or electrostatic chucking electrodes, are formed on selected ones of the U and / or L ceramic green sheets. In some examples, the electrodes are formed by printing a metal powder on the ceramic green sheets.

[0081] At 1228, the L ceramic green sheets are rotationally aligned (to align the features) and placed in contact to form a first stack. At 1230, a porous plug material is optionally placed in one or more features of the L ceramic green sheets. In some examples, the porous plug material comprises a green sheet material that is different from the green sheet material used for the top and bottom of the ESC body. At 1232, U ceramic green sheets are rotationally aligned (to align the features) and placed in contact to form a second stack. At 1232, a porous plug material is optionally placed in the features of the U ceramic green sheets.

[0082] At 1236, the first stack is placed in contact with the second stack. At 1238, the first stack and the second stack are heated or fired to form a monolithic ESC body. In some examples, the ESC stack is heated to a temperature ranging from 1000°C to 2000°C. At 1242, sensors and terminals are optionally installed. At 1246, one or more surfaces of the ESC body are machined as needed. Machining can be used to flatten the surface of the ESC body. As can be appreciated, the order of one or more steps can be changed from the foregoing example.

[0083] 13 , another method 1300 for fabricating an ESC with a monolithic body is shown. At 1310, L ceramic green sheets are selected for the lower part of the ESC body. At 1314, features are cut into one or more of the L ceramic green sheets to define the features for the lower part of the ESC body. At 1324, electrodes are optionally formed on selected ones of the L ceramic green sheets.

[0084] At 1332, the L ceramic green sheets are placed in contact to form a stack. At 1334, a porous plug material is optionally placed in one or more features of the L ceramic green sheets. At 1338, the stack is heated to form the lower part of the ESC body. At 1340, the top surface of the lower part of the ESC body is optionally machined.

[0085] At 1342, a dielectric material and / or a conductor material is deposited. In some examples, the dielectric material and / or the conductor material is deposited using a deposition process such as atomic layer deposition (ALD), chemical vapor deposition (CVD), spray coating, or other process. At 1346, sensors are optionally installed in one or more features of the ESC body. In some examples, multiple process steps including photolithography, deposition of dielectric material, conductive material, and / or masking material, and / or etching are performed to define the RF terminal or electrostatic chucking terminal and the surrounding dielectric material. As can be appreciated, the quality of the dielectric material in the upper part of the ESC body can be higher than the ceramic green sheet used in the lower part of the ESC body.

[0086] In some instances, ESCs with monolithic bodies can be used for higher power applications. While prior art designs including separate ceramic plates, metal bodies, and bonding layers were limited to 10 kW to 20 kW, ESCs with monolithic bodies can be used at power levels of 10 kW to 50 kW or more. As can be appreciated, using higher power allows for higher etch rates.

[0087] The foregoing description is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the present disclosure can be embodied in a variety of forms. Accordingly, while the present disclosure includes specific examples, the true scope of the disclosure should not be limited to such examples, as other modifications will become apparent upon review of the drawings, the specification, and the following claims. It should be understood that one or more steps in a method may be performed in a different order (or simultaneously) without altering the principles of the present disclosure. Furthermore, although each embodiment is described above as having particular features, any one or more of these features described with respect to any embodiment of the present disclosure may be implemented in other embodiments and / or combined with any features of the other embodiments (even if such combination is not explicitly described). In other words, the described embodiments are not mutually exclusive, and substituting one or more embodiments for one another is within the scope of the present disclosure.

[0088] Spatial and functional relationships between elements (e.g., modules, circuit elements, semiconductor layers, etc.) are described using various terms such as "connected," "engaged," "coupled," "adjacent," "next to," "on," "above," "below," and "disposed." Also, when a relationship between a first element and a second element is described in the above disclosure, unless expressly described as "direct," the relationship may be a direct relationship where no other intervening elements exist between the first element and the second element, or an indirect relationship where one or more intervening elements (spatial or functional) exist between the first element and the second element. As used herein, the phrase "at least one of A, B, and C" should be interpreted in the sense of a logical (A or B or C) using a non-exclusive logical OR, and not in the sense of "at least one of A, at least one of B, and at least one of C."

[0089] In some embodiments, the controller is part of a system, and such a system may be part of the examples described above. Such systems may include semiconductor processing equipment, including one or more processing tools, one or more chambers, one or more processing platforms, and / or specific processing components (e.g., wafer pedestals, gas flow systems, etc.). These systems may be integrated with electronics for controlling system operation before, during, and after semiconductor wafer or substrate processing. Such electronics may be referred to as a "controller" and may control various components or subcomponents of one or more systems. The controller may be programmed to control any of the processes disclosed herein, depending on the processing requirements and / or type of system. Such processes may include process gas delivery, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, position and motion settings, wafer transfer to and from the tool, and wafer transfer to and from other transfer tools and / or load locks connected or interfaced with the particular system.

[0090] Broadly, a controller may be defined as an electronic device having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operations, enable cleaning operations, enable endpoint measurements, etc. Integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application-specific integrated circuits (ASICs), and / or one or more microprocessors, i.e., microcontrollers, that execute program instructions (e.g., software). Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files) that define operational parameters for performing a particular process on or for a semiconductor wafer or for a system. The operational parameters, in some embodiments, may be part of a recipe defined by a process engineer to implement one or more processing steps in the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or wafer dies.

[0091] In some embodiments, the controller may be part of, coupled to, or a combination of a computer integrated with, coupled to, or otherwise networked to the system. For example, the controller may be in the “cloud” or all or part of a fab host computer system. This allows for remote access to wafer processing. The computer may provide remote access to the system to monitor the current progress of a fabrication operation, review the history of past fabrication operations, review trends or performance criteria from multiple fabrication operations, modify parameters of a current process, configure processing steps following a current process, or initiate a new process. In some examples, a remote computer (e.g., a server) can provide process recipes to the system over a network. Such a network may include a local network or the Internet. The remote computer may include a user interface that allows entry or programming of parameters and / or settings, which are then communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of data. Such data identifies parameters for each processing step performed during one or more operations. It should be understood that the parameters may be specific to the type of process being performed and the type of tool the controller is configured to interface with or control. Thus, as discussed above, the controller may be distributed, for example, by having one or more individual controllers networked together and working together toward a common purpose (such as the processes and controls described herein). An example of a distributed controller for such purposes would include one or more integrated circuits on the chamber in communication with one or more integrated circuits located remotely (e.g., at the platform level or as part of a remote computer) and coupled to control the process in the chamber.

[0092] Exemplary systems may include, but are not limited to, a plasma etch chamber or module, a deposition chamber or module, a spin rinse chamber or module, a metal plating chamber or module, a cleaning chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a tracking chamber or module, and any other semiconductor processing system that may be associated with or used in the fabrication and / or manufacturing of semiconductor wafers.

[0093] As described above, depending on the process step or steps being performed by the tool, the controller may communicate with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, nearby tools, tools located throughout the factory, a main computer, another controller, or tools used in material transport to and from tool locations and / or load ports in a semiconductor fabrication factory.

Claims

1. An electrostatic chuck for a substrate processing system, a monolithic ceramic body; a plurality of first electrodes disposed on the monolithic body adjacent a top surface of the monolithic body and configured to selectively receive a chucking signal; a gas channel formed in the monolithic body and configured to supply a backside gas to the top surface; a plurality of coolant channels formed in the monolithic body and configured to receive a fluid to control a temperature of the monolithic body; An electrostatic chuck comprising:

2. 10. The electrostatic chuck of claim 1, The monolithic body comprises a plurality of ceramic green sheets.

3. 10. The electrostatic chuck of claim 1, the monolithic body comprises a first portion disposed adjacent to a substrate and a second portion located adjacent to the first portion, the first portion being made of a first plurality of ceramic green sheets having a first quality, and the second portion being made of a second plurality of ceramic green sheets having a second quality lower than the first quality.

4. 4. The electrostatic chuck of claim 3, the second plurality of ceramic green sheets have at least one of increased porosity, decreased purity, increased dielectric constant, or increased loss tangent compared to the first plurality of ceramic green sheets.

5. 10. The electrostatic chuck of claim 1, The electrostatic chuck, wherein the plurality of first electrodes are disposed between the plurality of coolant channels and the top surface.

6. 10. The electrostatic chuck of claim 1, The electrostatic chuck further comprises a plurality of second electrodes disposed on the monolithic body and configured to receive an RF bias signal.

7. 7. The electrostatic chuck of claim 6, The electrostatic chuck, wherein the plurality of second electrodes are disposed between the plurality of coolant channels and the plurality of first electrodes.

8. 10. The electrostatic chuck of claim 1, The electrostatic chuck further comprises a porous plug disposed in at least one of the inlet and outlet of the gas channel.

9. 10. The electrostatic chuck of claim 1, the monolithic body comprising a first portion disposed adjacent to a substrate and a second portion disposed adjacent to the first portion; the second portion is made of a plurality of ceramic green sheets; the first portion is deposited on the second portion and includes a plurality of ceramic layers and a conductive layer defining the plurality of first electrodes; Electrostatic chuck.

10. 10. The electrostatic chuck of claim 9, The electrostatic chuck, wherein the first portion is deposited using a process selected from the group consisting of atomic layer deposition and chemical vapor deposition.

11. 10. The electrostatic chuck of claim 1, The monolithic body defines a lift pin cavity, and the electrostatic chuck further comprises a lift pin assembly disposed in the lift pin cavity.

12. 1. A method for fabricating a monolithic electrostatic chuck, comprising: selecting a plurality of ceramic green sheets for the monolithic electrostatic chuck; cutting a plurality of features into a first selected one of the ceramic green sheets, the plurality of features being selected from the group consisting of gas channels, coolant channels, and lift pin cavities; forming a plurality of electrodes on a second selected one of the ceramic green sheets; aligning and arranging the plurality of ceramic green sheets in a stack; heating the stack to a predetermined temperature to form the monolithic electrostatic chuck; A method comprising:

13. 13. The method of claim 12, The method wherein the predetermined temperature is in the range of 1000°C to 2000°C.

14. 13. The method of claim 12, The method, wherein the plurality of features includes the coolant channels, the coolant channels extending through adjacent ones of the plurality of ceramic green sheets.

15. 13. The method of claim 12, the plurality of features include the gas channels, the gas channels extending through adjacent ones of the plurality of ceramic green sheets.

16. 16. The method of claim 15, The method further comprises disposing a porous plug material in at least one of the inlets and outlets of the gas channels before heating the stack.

17. 16. The method of claim 15, The method further comprises machining at least one surface of the monolithic electrostatic chuck after heating the stack.

18. 13. The method of claim 12, The method further comprising forming a plurality of electrodes on selected ones of the plurality of ceramic green sheets prior to heating.

19. 1. A method for fabricating a monolithic electrostatic chuck, comprising: providing U ceramic green sheets having a first quality, where U is an integer greater than 1; cutting a plurality of features into selected ones of the U ceramic green sheets; Aligning and arranging the U ceramic green sheets in a first stack; providing L ceramic green sheets having a second quality lower than the first quality, where L is an integer greater than 1; cutting a plurality of features into selected ones of the L ceramic green sheets; aligning and arranging the L ceramic green sheets in a second stack; positioning and aligning the first stack adjacent to the second stack; heating the first stack and the second stack; A method comprising:

20. 20. The method of claim 19, The method wherein the first stack and the second stack are heated to a temperature in the range of 1000°C to 2000°C.

21. 20. The method of claim 19, The method further includes, before heating the first stack and the second stack, forming a plurality of first electrodes configured to receive a chucking bias on selected sheets of the U ceramic green sheets.

22. 20. The method of claim 19, The method further includes forming a plurality of second electrodes configured to receive an RF bias on selected ones of the U ceramic green sheets before heating the first stack and the second stack.

23. 20. The method of claim 19, The method, wherein the L ceramic green sheets have at least one of increased porosity, decreased purity, increased dielectric constant, or increased loss tangent compared to the U ceramic green sheets.

24. 20. The method of claim 19, The method, wherein cutting the plurality of features includes forming a plurality of coolant channels in at least one of the U ceramic green sheets and the L ceramic green sheets before heating the first stack and the second stack.

25. 20. The method of claim 19, The method, wherein cutting the plurality of features includes forming a plurality of gas channels in at least one of the U ceramic green sheets and the L ceramic green sheets before heating the first stack and the second stack.

26. 26. The method of claim 25, The method further includes disposing a porous plug material in at least one of the inlets and outlets of the plurality of gas channels before heating the first stack and the second stack.

27. 20. The method of claim 19, The method further comprising machining at least one surface of the first stack after heating the first stack and the second stack.

28. 1. A method for fabricating a monolithic electrostatic chuck, comprising: selecting a plurality of ceramic green sheets for a lower portion of an electrostatic chuck body; cutting a plurality of features into selected ones of the plurality of ceramic green sheets; aligning and arranging the plurality of ceramic green sheets in a stack; heating the stack to a predetermined temperature; forming an upper portion of the electrostatic chuck body by depositing a plurality of layers on a top surface of the stack, the plurality of layers including ceramic and defining a plurality of electrodes; A method comprising:

29. 29. The method of claim 28, The method wherein the predetermined temperature is in the range of 1000°C to 2000°C.

30. 29. The method of claim 28, a first quality of ceramic material in the upper portion of the electrostatic chuck body is greater than a second quality of ceramic material in the lower portion of the electrostatic chuck body.

31. 29. The method of claim 28, The method, wherein the plurality of ceramic green sheets in the lower portion have at least one of increased porosity, decreased purity, increased dielectric constant, or increased loss tangent compared to the plurality of ceramic green sheets in the upper portion.

32. 29. The method of claim 28, The method, wherein the plurality of features comprises a plurality of coolant channels formed in adjacent ones of the plurality of ceramic green sheets.

33. 29. The method of claim 28, The method, wherein the plurality of features comprises a plurality of gas channels formed in adjacent ones of the plurality of ceramic green sheets.

34. 34. The method of claim 33, The method further comprising disposing a porous plug material in at least one of the inlets and outlets of the plurality of gas channels before heating the stack.

35. 29. The method of claim 28, The method further comprising machining at least one surface of the lower portion after heating the stack and before depositing the upper portion.

36. 29. The method of claim 28, The method, wherein the depositing the plurality of layers on the top surface of the stack comprises a process selected from the group consisting of atomic layer deposition and chemical vapor deposition.

37. 29. The method of claim 28, The method further comprising forming a plurality of electrodes on selected ones of the plurality of ceramic green sheets prior to heating.

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