WO2025128412A1

WO2025128412A1 - Cooled edge ring with securing mechanism

Info

Publication number: WO2025128412A1
Application number: PCT/US2024/058790
Authority: WO
Inventors: Ryan Bise; James Collin SPEEDY; Dmitry Opaits; John Holland
Original assignee: Lam Research Corp
Current assignee: Lam Research Corp
Priority date: 2023-12-11
Filing date: 2024-12-06
Publication date: 2025-06-19
Anticipated expiration: 2026-06-11
Also published as: TW202543055A

Abstract

A substrate support for a substrate processing chamber includes a baseplate, and an edge ring arranged on the baseplate. A radially outer bottom surface of the edge ring is coplanar with a radially inner bottom surface of the edge ring. The substrate support includes a seal arrangement located between the edge ring and the baseplate. The seal arrangement is configured to define an interface between the edge ring and the baseplate. The substrate support includes at least one channel in fluid communication with the interface and configured to supply a heat transfer gas to the interface.

Description

COOLED EDGE RING WITH SECURING MECHANISM

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63/608,666 filed on December 1 1 , 2023. The entire disclosure of the above application is incorporated herein by reference.

FIELD

[0002] The present disclosure relates to a novel edge ring and system for controlling edge ring temperature in a substrate processing system.

BACKGROUND

[0003] The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

[0004] Substrate processing systems may be used to treat substrates such as semiconductor wafers. Example processes that may be performed on a substrate include, but are not limited to, chemical vapor deposition (CVD), atomic layer deposition (ALD), conductor etch, dielectric etch, and/or other etch, deposition, or cleaning processes. A substrate may be arranged on a substrate support, such as a pedestal, an electrostatic chuck (ESC), etc. in a processing chamber of the substrate processing system. During etching, etch gas mixtures including one or more gases may be introduced into the processing chamber and plasma may be used to initiate chemical reactions.

[0005] The substrate support may include a ceramic layer arranged to support a substrate. For example, the substrate may be clamped to the ceramic layer during processing. The substrate support may include an edge ring arranged to surround an outer perimeter of the ceramic layer and the substrate. SUMMARY

[0006] A substrate support for a substrate processing chamber includes a baseplate, an edge ring arranged on the baseplate, wherein a radially outer bottom surface of the edge ring is coplanar with a radially inner bottom surface of the edge ring, a seal arrangement located between the edge ring and the baseplate, wherein the seal arrangement is configured to define an interface between the edge ring and the baseplate, and at least one channel in fluid communication with the interface and configured to supply a heat transfer gas to the interface.

[0007] In other features, the interface comprises a gap between the radially inner bottom surface of the edge ring and an upper surface of the baseplate. In other features, the gap has a depth of less than 25 microns.

[0008] In other features, the seal arrangement includes first and second annular seals and the interface is defined between the first and second annular seals.

[0009] In other features, the seal arrangement includes a third annular seal arranged between the first annular seal and the second annular seal, and wherein the third annual seal divides the interface into a first region and a second region.

[0010] In other features, the at least one channel includes a first channel in fluid communication with the first region and a second channel in fluid communication with the second region, and wherein the first channel and the second channel are configured to separately receive the heat transfer gas.

[0011] In other features, the seal arrangement includes two or more azimuthal seals extending in a radial direction between the first and second annular seals, wherein the two or more azimuthal seals divide the interface into two or more azimuthal zones configured to separately receive the heat transfer gas.

[0012] In other features, the substrate support includes a support ring configured to bias the edge ring downward toward the interface.

[0013] In other features, the substrate support includes a securing mechanism inserted through at least a portion of the support ring and a radially outer portion of the edge ring, to bias the edge ring downward. [0014] In other features, a height defined between a top surface of the securing mechanism and a top surface of the edge ring is in a range from 20% to 50% of a height of the edge ring.

[0015] In other features, the height defined between the top surface of the securing mechanism and the top surface of the edge ring is at least 33% of the height of the edge ring. In other features, the height of the edge ring is less than or equal to seven millimeters.

[0016] In other features, an air gap is defined between the radially outer bottom surface of the edge ring and the radially inner bottom surface of the edge ring, and a height of the air gap is in a range from 5% to 10% of a height of the edge ring.

[0017] In other features, the height of the air gap is 8% of the height of the edge ring. In other features, a length of the air gap is in a range of 10% to 30% of the length of the edge ring.

[0018] In other features, a length of the air gap is at least 19% of the length of the edge ring. In other features, the at least one channel is provided through the baseplate.

[0019] A system includes a substrate support and a heat transfer gas source configured to supply the heat transfer gas to the interface via the at least one channel. In other features, the system includes a controller configured to control the supply of the heat transfer gas to the interface to adjust a temperature of the edge ring.

[0020] A substrate support for a substrate processing chamber includes a baseplate, an edge ring arranged on the baseplate, wherein a radially lower surface of the edge ring includes first and second annular grooves, a support ring configured to bias the edge ring downward toward the baseplate, a securing mechanism inserted through at least a portion of the support ring and a radially outer portion of the edge ring, to bias the edge ring downward, wherein a height defined between a top surface of the securing mechanism and a top surface of the edge ring is at least 20% of a height of the edge ring, a first seal arranged in the first annular groove, and a second seal arranged in the second annular groove, wherein the first and second seals define an interface between the edge ring and the baseplate, wherein the interface is in fluid communication with a heat transfer gas source.

[0021] In other features, the height defined between the top surface of the securing mechanism and the top surface of the edge ring is at least 32% of the height of the edge ring. In other features, the height of the edge ring is less than or equal to seven millimeters.

[0022] An edge ring includes a top surface, a radially inner bottom surface parallel with the top surface, the radially inner bottom surface defining a radially inner groove configured to retain a first seal, and a radially outer groove configured to retain a second seal. A radially outer bottom surface is parallel with the top surface, the radially outer bottom surface defines a pocket configured to receive a securing mechanism for biasing the edge ring downwards, the pocket is perpendicular to the radially outer bottom surface and the top surface, and the pocket extends along only part of a height of the edge ring defined between the top surface and the radially outer bottom surface.

[0023] In other features, the radially inner bottom surface is coplanar with the radially outer bottom surface.

[0024] In other features, a height of the pocket is seventy percent or less of the height of the edge ring. In other features, the radially outer bottom surface comprises twenty to twenty-four pockets evenly spaced apart.

[0025] In other features, the height of the pocket is in a range between sixty-six and sixty-nine percent of the height of the edge ring.

[0026] In other features, a length of the radially inner bottom surface defined between the radially inner groove and the radially outer groove is at least thirty-four percent of a total length of the edge ring.

[0027] In other features, the length of the radially inner bottom surface is in a range between thirty-five and thirty-eight percent of the total length of the edge ring.

[0028] In other features, the radially outer bottom surface is spaced apart from the radially inner bottom surface by an air gap. In other features, a length of the air gap is in a range between ten percent and thirty percent of the length of the radially inner bottom surface.

[0029] In other features, the length of the radially inner bottom surface is at least fifty percent of the total length of the edge ring.

[0030] In other features, the length of the radially inner bottom surface is in a range between fifty-one and fifty-four percent of the total length of the edge ring. [0031] In other features, the radially inner groove is configured to retain a first O-ring, and the radially outer groove is configured to retain a second O-ring.

[0032] In other features, a height of the radially inner groove is in a range between ten percent and thirty percent of the height of the edge ring. In other features, a height of the radially inner groove is the same as a height of the radially outer groove. In other features, the height of the pocket is shorter than a height of the portion of the edge ring extending above the radially inner groove, the height of the pocket is taller than a height of the radially inner groove, and the height of the portion of the edge ring extending above the radially inner groove is less than the height of the edge ring. In other features, the securing mechanism comprises a screw.

[0033] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0035] FIG. 1 is an example substrate processing system according to the present disclosure;

[0036] FIG. 2A is an example substrate support according to the principles of the present disclosure;

[0037] FIG. 2B shows a bottom view of an edge ring including example seals defining azimuthal zones according to the principles of the present disclosure;

[0038] FIG. 3 illustrates an example edge ring and seals according to the principles of the present disclosure;

[0039] FIG. 4 illustrates an example edge ring including a pocket, according to principles of the present disclosure; and

[0040] FIG. 5 is a bottom view of an example edge ring according to principles of the present disclosure. [0041] In the drawings, reference numbers may be reused to identify similar and/or identical elements.

DETAILED DESCRIPTION

[0042] In a substrate processing chamber, a temperature of an edge ring affects processing parameters such as etch rate and uniformity at an outer edge of a substrate. The edge ring is exposed to the processing environment (including plasma) and it absorbs heat. Accordingly, the temperature of the edge ring varies during processing and controlling the temperature of the edge ring helps achieve a repeatable etch rate and process uniformity.

[0043] In some examples, the edge ring is arranged in thermal contact with a baseplate or lower ring of the substrate support. For example, the baseplate may function as a heat sink for the edge ring and heat is transferred via an interface between the edge ring and the baseplate. In some examples, a thermal interface material (e.g., a silicone-based material such as a gel, paste, pad, etc.) is provided between the edge ring and the baseplate to facilitate transfer of heat from the edge ring to the baseplate. The baseplate may include coolant channels configured to flow coolant and transfer heat out of the baseplate.

[0044] Controlling the temperature of the edge ring using direct heat transfer contact between the edge ring and the substrate support or in combination with a thermal interface material provides only passive temperature control. For example, the temperature of the edge ring will vary in accordance with radio frequency (RF) power delivered to the processing chamber, thermal conductivity of the interface and/or interface material, and contact area. Accordingly, heat transfer characteristics (e.g., a heat transfer coefficient) corresponding to heat transfer out of the edge ring cannot be changed without changing hardware or materials such as the thermal interface material.

[0045] Further, the thermal interface material (e.g., a silicone gel or paste) is difficult to install, may not have consistent properties in every processing chamber, and/or the properties of the thermal interface material may change over time, contributing to edge ring temperature drift. For example, the thermal interface material may be exposed to process materials (e.g., plasma), further degrading the heat transfer characteristics. Replacing the edge ring requires extensive cleaning of the substrate support to remove the thermal interface material. [0046] Systems and methods according to the present disclosure provide a heat transfer gas (e.g., helium and/or other suitable inert heat transfer gases) to the interface between the edge ring and the baseplate to facilitate temperature control. Pressure of the heat transfer gas may be controlled to adjust heat transfer characteristics during processing. For example, a bottom surface of the edge ring may include a sealing arrangement including an integrated or bonded (i.e., attached) seal configured to contain the heat transfer gas in the interface between the edge ring and the baseplate. The pressure of the heat transfer gas may be adjusted to compensate for differences between processing chambers and/or be adjusted during processing.

[0047] Referring now to FIG. 1 , an example substrate processing system 100 is shown. For example only, the substrate processing system 100 may be used for performing etching using RF plasma and/or other suitable substrate processing. The substrate processing system 100 includes a processing chamber 102 that encloses other components of the substrate processing system 100 and contains the RF plasma. The substrate processing chamber 102 includes an upper electrode 104 and a substrate support 106, such as an ESC. During operation, a substrate 108 is arranged on the substrate support 106. While a specific substrate processing system 100 and processing chamber 102 are shown as an example, the principles of the present disclosure may be applied to other types of substrate processing systems and processing chambers, such as a substrate processing system that generates plasma in-situ, that implements remote plasma generation and delivery (e.g., using a plasma tube, a microwave tube), etc.

[0048] For example only, the upper electrode 104 may include a gas distribution device such as a showerhead 110 that introduces and distributes process gases. The showerhead 1 10 may include a stem portion including one end connected to a top surface of the processing chamber 102. A base portion is generally cylindrical and extends radially outwardly from an opposite end of the stem portion at a location that is spaced from the top surface of the processing chamber. A substrate-facing surface or faceplate of the base portion of the showerhead 1 10 includes a plurality of holes through which process gas or purge gas flows. Alternately, the upper electrode 104 may include a conducting plate and the process gases may be introduced in another manner.

[0049] The substrate support 106 includes a conductive baseplate 1 12 that acts as a lower electrode. The baseplate 1 12 supports a ceramic layer 1 14. A bond layer (e.g., an adhesive and/or thermal bond layer) 116 may be arranged between the ceramic layer 1 14 and the baseplate 1 12. The baseplate 1 12 may include one or more coolant channels 118 for flowing coolant through the baseplate 1 12. The substrate support 106 may include an edge ring 120 arranged to surround an outer perimeter of the substrate 108.

[0050] An RF generating system 122 generates and outputs an RF voltage to one of the upper electrode 104 and the lower electrode (e.g., the baseplate 1 12 of the substrate support 106). The other one of the upper electrode 104 and the baseplate 112 may be DC grounded, AC grounded or floating. In the present example, the RF voltage is supplied to the lower electrode. For example only, the RF generating system 122 may include an RF voltage generator 124 that generates the RF voltage that is fed by a matching and distribution network 126 to the upper electrode 104 or the baseplate 112. In other examples, the plasma may be generated inductively or remotely. Although, as shown for example purposes, the RF generating system 122 corresponds to a capacitively coupled plasma (CCP) system, the principles of the present disclosure may also be implemented in other suitable systems, such as, for example only transformer coupled plasma (TCP) systems, CCP cathode systems, remote microwave plasma generation and delivery systems, etc.

[0051] A gas delivery system 130 includes one or more gas sources 132-1 , 132-2,..., and 132-N (collectively gas sources 132), where N is an integer greater than zero. The gas sources supply one or more etch gases and mixtures thereof. The gas sources may also supply carrier and/or purge gas. The gas sources 132 are connected 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) to a manifold 140. An output of the manifold 140 is fed to the processing chamber 102. For example only, the output of the manifold 140 is fed to the showerhead 1 10.

[0052] A temperature controller 142 may communicate with a coolant assembly 146 to control coolant flow through the channels 1 18. For example, the coolant assembly 146 may include a coolant pump and reservoir. The temperature controller 142 operates the coolant assembly 146 to selectively flow the coolant through the channels 1 18 to cool the substrate support 106.

[0053] A valve 150 and pump 152 may be used to evacuate reactants from the processing chamber 102. A system controller 160 may be used to control components of the substrate processing system 100. A robot 170 may be used to deliver substrates onto, and remove substrates from, the substrate support 106. For example, the robot 170 may transfer substrates between the substrate support 106 and a load lock 172. Although shown as separate controllers, the temperature controller 142 may be implemented within the system controller 160.

[0054] In the substrate support 106 according to the present disclosure, an interface 180 is defined between the edge ring 120 and an upper surface of the baseplate 1 12. For example, the edge ring 120 may contact and be supported on the upper surface of the baseplate 112. A heat transfer gas such as helium is supplied from a heat transfer gas source 182 to the interface 180. The heat transfer gas facilitates cooling of the edge ring 120 (i.e., heat transfer from the edge ring 120 to baseplate 1 12. Although shown separately, the heat transfer gas source 182 may be implemented within the gas delivery system 130. The temperature controller 142 (and/or the system controller 160) may be configured to adjust a pressure of the heat transfer gas supplied to the interface 180 to adjust the temperature of the edge ring 120.

[0055] Referring now to FIG. 2A, a portion of an example substrate support 200 according to the present disclosure is shown. The substrate support 200 is configured to support a substrate 204. The substrate support 200 includes a baseplate (e.g., a conductive baseplate) 208, a ceramic layer 212, and, in some examples, a bond layer 214 arranged between the ceramic layer 212 and the baseplate 208. The baseplate 208 may include one or more coolant channels 216 for flowing coolant through the baseplate 208. The substrate support 200 includes an edge ring 220 arranged to surround an outer perimeter of the substrate 204.

[0056] The substrate support 200 includes one or more channels 224 (e.g., between one and ten of the channels 224 spaced annularly around the baseplate 208) arranged to provide a heat transfer gas such as helium from a heat transfer gas source 228 to an interface 232 between the edge ring 220 and the baseplate 208 (e.g., to a backside of the edge ring 220). For example, the channels 224 are provided through the baseplate 208 and are in fluid communication with the interface 232. Although the interface 232 is shown with a small gap for example purposes, the edge ring 220 may be supported directly on the upper surface of the baseplate 208. The heat transfer gas facilitates control of the temperature of the edge ring 220. [0057] A temperature controller 236 communicates with a coolant assembly 240 to control coolant flow through the channels 216. The temperature controller 236 communicates with the heat transfer gas source 228 to control flow of the heat transfer gas (e.g., via valves of a gas delivery system such as the gas delivery system 130 described above in FIG. 1 ). The temperature controller 236 may also operate the coolant assembly 240 to selectively flow the coolant through the channels 216 to cool the substrate support 200. The temperature controller 236 may be a separate controller, implemented within a system controller 244, etc.

[0058] The temperature controller 236 may be configured to measure and/or calculate a temperature of the edge ring 220 based in part on sensed and/or modeled temperatures of the substrate support 200 and the edge ring 220, process parameters, etc. For example, the temperature controller 236 determines the temperature of the edge ring 220 in accordance with temperatures of the substrate support 200 and the edge ring 220 as measured using one or more temperature sensors (not shown). In other examples, the temperature controller 236 may be configured to calculate the temperature of the edge ring 220 using other measured and/or estimated values, such as an output of a model. For example, the temperature controller 236 may receive one or more signals 252 corresponding to directly sensed temperatures and/or other process parameters used to calculate the temperature of the edge ring 220.

[0059] The temperature controller 236 may determine the flow and/or pressure of the heat transfer gas from one or more sensors 256 arranged between the heat transfer gas source 228 and the substrate support 200. For example, the sensors 256 may correspond to sensors measuring heat transfer gas flow (and/or pressure) provided to the interface 232. The temperature controller 236 is configured to adjust the pressure of the heat transfer gas based on the determined temperature of the edge ring 220 and a desired temperature of the edge ring 220. In other words, the temperature controller 236 may increase or decrease the pressure of the heat transfer gas to decrease or increase the temperature of the edge ring 220 to achieve the desired temperature (e.g., to tune a plasma edge sheath).

[0060] In this example, a bottom surface of the edge ring 220 includes a sealing arrangement such as integrated or bonded (i.e., attached) seals 260 configured to contain the heat transfer gas within the interface 232. For example, the seals 260 may be O-rings or other sealing structures comprised of an elastomer or silicone material. In some examples, a bottom surface of the edge ring 220 and/or the upper surface of the baseplate 208 may include one or more recesses or grooves configured to accommodate the seals 260. A distance between the seals 260 may be varied to vary a width of the interface 232. The seals 260 prevent leaking of the heat transfer gas into a processing environment (e.g., a plasma/vacuum environment). Conversely, the seals 260 prevent loss of vacuum in the processing environment.

[0061] The edge ring 220 may be biased downward toward the baseplate 208 to compress the seals 260. For example, the edge ring 220 may be biased downward such that the lower surface of the edge ring 220 contacts the upper surface of the baseplate 208 and a consistent gap (e.g., a gap having a depth in range between 1 and 25 microns) is maintained in both annular and radial directions. Because the heat transfer characteristics are increased with a smaller gap, the gap is minimized to maximize heat transfer out of the edge ring 220 and into the baseplate 208 via the heat transfer gas.

[0062] As shown, the edge ring 220 is biased downward using a securing mechanism such as a screw 264 configured to pull the edge ring 220 toward a support ring 268. In some examples, a linear actuator 270 is configured to pull the support ring 268 downward, which in turn pulls the edge ring 220 downward. For example, the support ring 268 may be arranged on an outer ring 272 (e.g., a ring comprising quartz or another insulative material). An outer surface of the linear actuator 270 and inner surfaces of a channel extending through the outer ring 272 and into the support ring 268 may be complementarily thread. Although FIG. 2A illustrates the securing mechanism as a screw 264, in other example embodiments the securing mechanism may include any other suitable mechanism for biasing the edge ring 220 downward, such as other types of fasteners, etc.

[0063] Although the edge ring 220 and the support ring 268 are shown as separate components, in other examples the edge ring 220 and the support ring 268 may comprise a single, integrated component. The downward force exerted on the edge ring 220 opposes upward biasing of the seal 260 and the pressure of the heat transfer gas within the interface 232 and retains the edge ring 220 against the upper surface of the baseplate 208. In other examples, another clamping mechanism may be used. One or more seals (e.g., O-rings; not shown) may be provided as a vacuum break between the support ring 268 and the outer ring 272, between the baseplate 208 and the outer ring 272, etc. [0064] In some examples, another optional seal 280 may be arranged between the seals 260 to divide the interface 232 into two separate regions and respective gaps (i.e., inner and outer annular regions). In this example, the heat transfer gas may be separately provided to the different regions to separately control the heat transfer (and respective temperatures) of different radial regions of the edge ring 220 to compensate for radial non-uniformities. For example, a first channel 224 may be in fluid communication with a first region on one side of the optional seal 280, and a second channel 224 may be fluid communication with a second region on a second side of the optional seal 280. The first and second channels 224 may separately receive the heat transfer gas. In other examples, additional seals (not shown) may be provided to further divide the interface 232 into multiple, separate regions. In other examples, there are multiple heat transfer gas sources, each in fluid communication with a corresponding region (e.g., via different ones of multiple channels 224).

[0065] In one example, a single heat transfer gas source 228 provides the heat transfer gas to all of the channels 224. In other examples, multiple heat transfer gas sources 228 may be provided to separately supply the heat transfer gas to respective ones of the channels 224. For example, FIG. 2B shows a bottom view of the edge ring 220 in an arrangement where the seals 260 further include a plurality of azimuthal seals 284 extending in a radial direction from an inner to an outer perimeter of the edge ring 220. The seals 284 separate the interface 232 into multiple azimuthal zones 288. The heat transfer gas may be separately provided to the zones 288 via respective ones of the channels 224. In this manner, heat transfer from (and, accordingly, temperature of) the zones 288 may be separately controlled to compensate for azimuthal non-uniformities.

[0066] FIGS. 3 shows another example edge ring 300, including an implementation of a sealing arrangement 308 according to the present disclosure. In FIG. 3, the sealing arrangement 308 is integrated directly in or on a radially inner bottom surface 316 of the edge ring 300. For example, the radially inner bottom surface 316 includes a lower portion defining inner and outer grooves 320 and 324 configured to retain respective inner and outer portions 308-1 and 308-2 (e.g., O-rings) of the sealing arrangement 308. The radially outer bottom surface 318 on an outer portion (e.g., a shoulder) of the edge ring 300 is substantially flat.

[0067] In one example, the inner and outer portions 308-1 and 308-2 of the sealing arrangement 308 are bonded (e.g., using an adhesive) within the grooves 320 and 324. In another example, one or both of the inner and outer portions 308-1 and 308-2 may be retained within the respective grooves 320 and 324 without an adhesive. For example, the outer portion 308-2 of the sealing arrangement 308 may have a slightly smaller diameter than a height of the groove 324 and is stretched for insertion into the groove 324. Conversely, the inner portion 308-1 of the sealing arrangement 308 may have a slightly greater diameter than a height of the groove 320 and is compressed for insertion into the groove. In still another example, the sealing arrangement 308 comprises an elastomer, silicone, epoxy, etc. that is dispensed directly into the grooves 320 and 324.

[0068] The height of the groove 324 may correspond to dimensions of the outer portion 308-2 of the sealing arrangement 308, to achieve desired amount of compression for sealing (which may vary based on a material used, etc.). In some example embodiments, the height of the groove 324 is approximately 1.07-1.17 millimeters, although other example embodiments may use other values (such as a range of 0.57-2.26 millimeters).

[0069] The groove 324 may have a width sufficient for housing the outer portion 308-2 of the sealing arrangement 308. A larger width of the groove 324 may simplify the design of the edge ring 300 (e.g., for cost reasons, etc.), as opposed to having multiple height changes to the groove 324. In some example embodiments, the width of the groove 324 is approximately 2.8-3.3 millimeters, although other example embodiments may use other values (such as a range of 1.5-6 millimeters). In some embodiments, the groove 324 comprises at least one rounded corner that reduces the likelihood of chipping. In some embodiments the groove 324 comprises at least one chamfered corner which may facilitate alignment.

[0070] Accordingly, in the example shown in FIG. 3, the sealing arrangement 308 can be installed and/or removed when the edge ring 300 is installed or removed without requiring separate installation or removal. Further, in examples where the edge ring 300 is moveable (e.g., for tuning), the sealing arrangement 308 is automatically raised and lowered with the edge ring 300. In these examples, the supply of the heat transfer gas may be stopped when the edge ring 300 is raised.

[0071] As shown in FIG. 3, the edge ring 300 is biased downward using a securing mechanism 364 configured to pull the edge ring 300 toward a support ring 368. In some examples, the securing mechanism comprises a screw or any other fastener. In some examples, a linear actuator is configured to pull the support ring 368 downward, which in turn pulls the edge ring 300 downward. For example, the support ring 368 may be arranged on an outer ring (e.g., a ring comprising quartz or another insulative material), as shown in FIG. 2A. An outer surface of the linear actuator and inner surfaces of a channel extending through the outer ring and into the support ring 368 may be complementarily thread.

[0072] In some embodiments, the edge ring comprises a plurality of screw holes (i.e., pockets) for securing the edge ring 300 to the support ring 368. In some embodiments, the distances between a screw hole (i.e., from the inner radial edge of the screw 364) and the corresponding outer groove 324 are the same for all the screw holes. This allows for uniform distribution of pull force along the perimeter of the edge ring. In some examples, the screw 364 may be placed closer to the corresponding outer groove 324 than the outer diameter of the edge ring 300, to avoid a thin wall which could reduce structural integrity of the edge ring 300. Having the screw 364 further away from the exposed areas outside the edge ring 300 may better protect the screw 364 from plasma radicals.

[0073] In the example of FIG. 3, a radially outer bottom surface 318 of the edge ring 300 (e.g., a bottom surface of a radially outer portion of the edge ring 300), may be in contact with a top surface of the support ring 368. For example, the radially outer bottom surface 318 of the edge ring 300 may be biased against the support ring 368 by the screw 364.

[0074] In some example embodiments, the radially outer bottom surface 318 may be substantially coplanar with the radially inner bottom surface 316 of the edge ring 300. Substantially coplanar may refer to being coplanar within manufacturing tolerances, within 5% or 10% of being in the exact same plane, etc. This allows for a greater thickness of the radially outer portion of the edge ring 300, compared to edge rings where the radially outer bottom surface 318 is higher than the radially inner bottom surface 316 at a radially inner portion of the edge ring 300, especially when the top surface of the edge ring is flat across the inner portion and the outer portion of the edge ring.

[0075] A greater thickness of the radially outer portion of the edge ring 300 allows for an increased amount of material above the screw 364. For example, the screw 364 may be inserted to a lower height with respect to a top surface 319 of the edge ring 300. Therefore, the edge ring 300 may experience an increased amount of wear before replacement is needed, due to the increased amount of material above the screw 364 in the radially outer portion of the edge ring 300.

[0076] For example, a height d4 of the outer portion of the edge ring 300 is defined between the radially outer bottom surface 318 and the top surface 319 of the edge ring 300. A height d3 is defined between the top of the screw hole for receiving the screw 364 and the top surface 319 of the edge ring 300. In some example embodiments, the height d3 may be in a range of 20% to 50% of the height d4, such as at least about 30% of the height of d4. In some embodiments, d3 is structured to be about 31 %-34% of d4 based on the trade-off described below. For example, the height d3 defined between the top surface of the securing mechanism (e.g., the screw 364) and the top surface 319 of the edge ring 300 may be at least 32% of the height d4 of the edge ring 300. In other embodiments, the ratio may be greater or lesser. The height d4 may be less than or equal to seven millimeters in some examples. In some examples, the height of the pocket receiving the screw 364 is shorter than the height d3 of the portion of the edge ring 300 extending above the radially inner groove 320, but taller than the height d6 of the radially inner groove 320. The height of the portion of the edge ring 300 extending above the radially inner groove 320 may be less than the height d4 of the edge ring. The load on the screw 364 is a function of the number of screws used in the overall edge ring 300, and the number of threads engaged for each individual screw 364. A finer thread pattern may facilitate use of shorter screws, thereby allowing for a greater amount of material above the screw 364. Locating the screw 364 and a pocket for receiving the screw 364 near an outer diameter of the edge ring 300 may allow for increased heat transfer for the edge ring 300.

[0077] A length d2 of the edge ring 300 is defined from a radially inner surface of the edge ring to a radially outer surface of the edge ring 300, and while the inner portion 308- 1 and the outer portion 308-2 of the sealing arrangement 308 each have a diameter d6. In some example embodiments, the diameter d6 may be in a range of 10% to 30% of the height d4 of the edge ring 300, such as at least about 21 % of the height d4 of the edge ring 300. The diameter d6 may be in a range of about 2% to 10% of the length d2 of the edge ring, such as at least 4% of the length d2.

[0078] A height of the groove 320 which receives the seal may correspond to the diameter d6 of the inner portion 308-1 of the sealing arrangement 308, in order to accommodate the height of the seal. The height may be selected to facilitate a seal which is large enough to achieve a desired compression within tolerances.

[0079] A height of the extending portion of the edge ring 300 above the groove 320 may correspond to a height of the chuck, so that it matches up with the chuck height without touching the wafer. Rounded corners may be used along the extending portion of the edge ring to avoid chipping and damage, such as plasma creating an arc on sharp corners. On a top surface of the edge ring 300 where there is more plasma, there may be more gradual transitions in the corners.

[0080] An angle of the slant 317 on the top surface of the edge ring may be selected for edge of wafer process performance, such as tilt, edge rate, lifetime duration, etc. In some example embodiments, the angle of the slant 317 on the top surface of the edge ring is approximately 1 10-120 degrees.

[0081] A length d1 of the radially inner bottom surface 316 of the edge ring 300 may control an amount of capacitive coupling, such as an amount of RF energy coming from the baseplate 310 to the edge ring 300. If the length d1 is shortened, the capacitive coupling is reduced, but this may also reduce heat transfer between the baseplate 310 and the edge ring 300. In some example embodiments, the length d1 may be in a range of 30% to 60% of the length d2 of the edge ring 300, such as at least 50% of the length d2. In some embodiments, d1 is between 51 -54% of d2. In some embodiments d2 is between 30mm to 40mm. The ratio of the length d1 to the length d2 can be modified to affect an amount of capacitance between the baseplate 310 and the edge ring 302, while also determining a desired amount of heat transfer.

[0082] An upper corner 309 of the edge ring 300 may be rounded, based on polymer deposition for certain processes. Sharp corners (e.g., a chamfer), may facilitate polymer deposit on a sidewall, which can flake off and create an arc event. A rounded corner may provide higher reliability. Although FIG. 3 illustrates the lower outer edge (i.e. below the upper corner 309) as square, in other example embodiments it may be rounded. The rounded corner may be smaller at the lower outer edge, because the lower surface of the edge ring 300 is less exposed to polymer deposition, and is protected by an outer edge ring.

[0083] FIG. 4 shows another example edge ring 302, including an implementation of a sealing arrangement 308 according to the present disclosure. In FIG. 4, the sealing arrangement 308 is integrated directly in or on a radially inner bottom surface 316 of the edge ring 300. For example, the radially inner bottom surface 316 includes a lower portion defining inner and outer grooves 320 and 324 configured to retain respective inner and outer portions 308-1 and 308-2 (e.g., O-rings) of the sealing arrangement 308. The radially outer bottom surface 318 on an outer portion (e.g., a shoulder) of the edge ring 300 is substantially flat.

[0084] In the example shown in FIG. 4, the sealing arrangement 308 can be installed and/or removed when the edge ring 302 is installed or removed without requiring separate installation or removal. Further, in examples where the edge ring 302 is moveable (e.g., for tuning), the sealing arrangement 308 is automatically raised and lowered with the edge ring 302. In these examples, the supply of the heat transfer gas may be stopped when the edge ring 302 is raised.

[0085] As shown in FIG. 4, the edge ring 302 is biased downward using a securing mechanism such as a screw 364 configured to pull the edge ring 302 toward a support ring 368. In some examples, a linear actuator is configured to pull the support ring 368 downward, which in turn pulls the edge ring 302 downward.

[0086] In the example of FIG. 4, a radially outer bottom surface 318 of the edge ring 300 (e.g., a bottom surface of a radially outer portion of the edge ring 302), may be in contact with a top surface of the support ring 368. For example, the radially outer bottom surface 318 of the edge ring 302 may be biased against the support ring 368 by the screw 364.

[0087] In some example embodiments, the radially outer bottom surface 318 may be substantially coplanar with the radially inner bottom surface 316 of the edge ring 302. For example, the radially outer bottom surface 318 may be substantially parallel with a bottom surface of the edge ring 302 which is located at a radially inner portion of the edge ring 302. This allows for a greater thickness of the radially outer portion of the edge ring 302, compared to edge rings where the radially outer bottom surface 318 is higher than the radially inner bottom surface 316 at a radially inner portion of the edge ring 302.

[0088] A greater thickness of the radially outer portion of the edge ring 300 allows for an increased amount of material above the screw 364. For example, the screw 364 may be inserted to a lower height with respect to a top surface 319 of the edge ring 302. Therefore, the edge ring 302 may experience an increased amount of wear before replacement is needed, due to the increased amount of material above the screw 364 in the radially outer portion of the edge ring 302.

[0089] A length d8 of the radially inner bottom surface 316 of the edge ring 302 may control an amount of capacitive coupling, such as an amount of RF energy coming from the baseplate 310 to the edge ring 302. If the length d8 is shortened, the capacitive coupling is reduced, but this may also reduce heat transfer between the baseplate 310 and the edge ring 302. In some example embodiments, the length d8 may be in a range of 30% to 60% of the length d2 of the edge ring 302, such as at least 34% of the length d2. In some embodiments, d8 is about 35-38% of d2. The ratio of the length d8 to the length d2 is a tuning feature which controls an amount of capacitance between the baseplate 310 and the edge ring 302, while also determining a desired amount of heat transfer.

[0090] The edge ring 302 includes an air gap 303 located between the outer groove 324 and the radially outer bottom surface 318. The air gap 303 may be large enough to cause capacitive coupling to be low at the air gap 303 (e.g., capacitive coupling between the baseplate 310 and the edge ring 302). The air gap 303 may also be designed to be small enough that plasma cannot be maintained in the air gap 303. For example, a height d5 of the air gap 303 may be in a range of 5% to 10% of the height d4 of the edge ring 302, such as at least 8% of the height d4. A length d7 of the air gap 303 may be in a range of 10% to 30% of the length d2 of the edge ring 302, such as at least 19% of the length d2.

[0091] In other example embodiments, the radially inner bottom surface 316 may be substantially flat and not include the grooves 320 and 324. Instead, the sealing arrangement 308 may correspond to a gasket comprising a thermal interface material that is directly bonded to the lower portion. For example, the gasket is bonded to the radially inner bottom surface 316 using a thermal adhesive. The gasket may include downward-extending inner and outer rims defining a plenum and the heat transfer gas is supplied to the plenum. The rims are compressed against an upper surface of the baseplate and seal the heat transfer gas within the plenum. For example only, the plenum may be etched into a lower surface of the gasket using a laser to achieve a consistent desired depth (e.g., between 1 and 25 microns).

[0092] In another example embodiment, the sealing arrangement 308 includes a plenum formed in the radially inner bottom surface 316 of the edge ring 302 and downward-extending inner and outer rims define the plenum. The heat transfer gas is supplied to the plenum. The rims are compressed against an upper surface of the baseplate and seal the heat transfer gas within the plenum. For example, lower surfaces of the rims are smooth (e.g., flat) and, in some examples, may be polished to improve a seal between the edge ring 302 and the upper surface of the baseplate 310.

[0093] For example only, the plenum may be directly etched into the radially inner bottom surface 316 of the edge ring 302. For example, the plenum may be etched using a laser (e.g., laser ablation) to achieve a consistent desired depth. In other examples, the edge ring 302 may be machined to form the plenum. In some embodiments, the desired depth of the plenum is about 1 micron to 25 microns.

[0094] FIG. 5 is a bottom view of an example edge ring 502 according to principles of the present disclosure. The edge ring 502 includes multiple screw holes 507 (i.e., pockets) for receiving screws, to pull the edge ring 502 towards a support ring for example. Although FIG. 5 illustrates twenty four screw holes spaced at angles d11 of about fifteen degrees apart, other example embodiments may include more or less screw holes 507, with greater or lesser angles between them. For example, depending on the size and thread characteristic of the screw, the edge ring 502 may have thirty six screw holes spaced about ten degrees apart, thirty screw holes spaced about twelve degrees apart, twenty screw holes spaced about eighteen degrees apart, eighteen screw holes spaced about twenty degrees apart, or fifteen screw holes spaced about twenty four degrees apart. In some example embodiments, the screw holes are placed approximately equal distance apart with about +/- 3% positional variant.

[0095] For example, the screw holes 507 may be spaced to provide an appropriate load on each screw while pulling down the edge ring 502. The number and spacing of screw holes 507 may be selected to avoid a screw pulling out of silicon based on mechanical properties of the edge ring 502, and to meet a safety factor and avoid a screw breaking through the edge ring 502. More screw holes 507 places less load on each screw, and also provides increases uniformity across the edge ring 502.

[0096] As shown in FIG. 5, the edge ring 502 includes a flat surface 505 along the inner diameter d9 of the edge ring 502. For example, the circular inner diameter d9 of the edge ring 502 may transition to the flat surface 505 at a point 503 along the inner diameter d9. A distance d12 from the center of the edge ring 502 to the flat surface 505 may be less than half of the diameter d9.

[0097] In some example embodiments, an angle d10 between a midpoint of the flat surface 505 and one of the screw holes 507 may be about 7.5 degrees, although other angles (including zero degrees) may be used in other example embodiments. In some example embodiments, the angle d10 may be half of the angle d11 between two screws. The flat surface 505 may correspond to a notch of a wafer, where the flat surface 505 blocks plasma ions from going through the wafer notch to damage a ceramic surface of the chuck.

[0098] The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure.

[0099] Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.” [0100] In some implementations, a controller is part of a system, which may be part of the above-described examples. Such systems can comprise semiconductor processing equipment, including a processing tool or tools, chamber or chambers, a platform or platforms for processing, and/or specific processing components (a wafer pedestal, a gas flow system, etc.). These systems may be integrated with electronics for controlling their operation before, during, and after processing of a semiconductor wafer or substrate. The electronics may be referred to as the “controller,” which may control various components or subparts of the system or systems. The controller, depending on the processing requirements and/or the type of system, may be programmed to control any of the processes disclosed herein, including the delivery of processing gases, 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, positional and operation settings, wafer transfers into and out of a tool and other transfer tools and/or load locks connected to or interfaced with a specific system.

[0101] Broadly speaking, the controller may be defined as electronics having various integrated circuits, logic, memory, and/or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The 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, or 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), defining operational parameters for carrying out a particular process on or for a semiconductor wafer or to a system. The operational parameters may, in some embodiments, be part of a recipe defined by process engineers to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and/or dies of a wafer.

[0102] The controller, in some implementations, may be a part of or coupled to a computer that is integrated with the system, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the “cloud” or all or a part of a fab host computer system, which can allow for remote access of the wafer processing. The computer may enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from a plurality of fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process. In some examples, a remote computer (e.g. a server) can provide process recipes to a system over a network, which may include a local network or the Internet. The remote computer may include a user interface that enables 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, which specify parameters for each of the processing steps to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process to be performed and the type of tool that the controller is configured to interface with or control. Thus as described above, the controller may be distributed, such as by comprising one or more discrete controllers that are networked together and working towards a common purpose, such as the processes and controls described herein. An example of a distributed controller for such purposes would be one or more integrated circuits on a chamber in communication with one or more integrated circuits located remotely (such as at the platform level or as part of a remote computer) that combine to control a process on the chamber.

[0103] Without limitation, example systems may include a plasma etch chamber or module, a deposition chamber or module, a spin-rinse chamber or module, a metal plating chamber or module, a clean 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 track chamber or module, and any other semiconductor processing systems that may be associated or used in the fabrication and/or manufacturing of semiconductor wafers.

[0104] As noted above, depending on the process step or steps to be performed by the tool, the controller might communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, or tools used in material transport that bring containers of wafers to and from tool locations and/or load ports in a semiconductor manufacturing factory.

Claims

CLAIMS What is claimed is:

1 . A substrate support for a substrate processing chamber, the substrate support comprising: a baseplate; an edge ring arranged on the baseplate, wherein a radially outer bottom surface of the edge ring is coplanar with a radially inner bottom surface of the edge ring; a seal arrangement located between the edge ring and the baseplate, wherein the seal arrangement is configured to define an interface between the edge ring and the baseplate; and at least one channel in fluid communication with the interface and configured to supply a heat transfer gas to the interface.

2. The substrate support of claim 1 , wherein the interface comprises a gap between the radially inner bottom surface of the edge ring and an upper surface of the baseplate.

3. The substrate support of claim 2, wherein the gap has a depth in a range of 1 to 25 microns.

4. The substrate support of claim 1 , wherein the seal arrangement includes first and second annular seals and the interface is defined between the first and second annular seals.

5. The substrate support of claim 4, wherein the seal arrangement includes a third annular seal arranged between the first annular seal and the second annular seal, and wherein the third annular seal divides the interface into a first region and a second region.

6. The substrate support of claim 5, wherein the at least one channel includes a first channel in fluid communication with the first region and a second channel in fluid communication with the second region, and wherein the first channel and the second channel are configured to separately receive the heat transfer gas.

7. The substrate support of claim 4, wherein the seal arrangement includes two or more azimuthal seals extending in a radial direction between the first and second annular seals, wherein the two or more azimuthal seals divide the interface into two or more azimuthal zones configured to separately receive the heat transfer gas.

8. The substrate support of claim 1 , further comprising a support ring configured to bias the edge ring downward toward the interface.

9. The substrate support of claim 8, further comprising a securing mechanism inserted through at least a portion of the support ring and a radially outer portion of the edge ring, to bias the edge ring downward.

10. The substrate support of claim 9, wherein a height defined between a top surface of the securing mechanism and a top surface of the edge ring is in a range from 20% to 50% of a height of the radially outer portion of the edge ring.

1 1. The substrate support of claim 10, wherein the height defined between the top surface of the securing mechanism and the top surface of the edge ring is at least 32% of the height of the edge ring.

12. The substrate support of claim 10, wherein the height of the edge ring is less than or equal to seven millimeters.

13. The substrate support of claim 1 , wherein: an air gap is defined between the radially outer bottom surface of the edge ring and the radially inner bottom surface of the edge ring; and a height of the air gap is in a range from 5% to 10% of a height of the edge ring.

14. The substrate support of claim 13, wherein the height of the air gap is 8% of the height of the edge ring.

15. The substrate support of claim 13, wherein a length of the air gap is in a range of 10% to 30% of the length of the edge ring.

16. The substrate support of claim 15, wherein the length of the air gap is at least 19% of the length of the edge ring.

17. The substrate support of claim 1 , wherein the at least one channel is provided through the baseplate.

18. A system comprising the substrate support of claim 1 and further comprising a heat transfer gas source configured to supply the heat transfer gas to the interface via the at least one channel.

19. The system of claim 18, further comprising a controller configured to control the supply of the heat transfer gas to the interface to adjust a temperature of the edge ring.

20. An edge ring comprising: a top surface; a radially inner bottom surface parallel with the top surface, the radially inner bottom surface defining: a radially inner groove configured to retain a first seal; and a radially outer groove configured to retain a second seal; and a radially outer bottom surface parallel with the top surface, the radially outer bottom surface defines a pocket configured to receive a securing mechanism for biasing the edge ring downwards, wherein the pocket is perpendicular to the radially outer bottom surface and the top surface, and wherein the pocket extends along only part of a height of the edge ring defined between the top surface and the radially outer bottom surface.

21 . The edge ring of claim 20, wherein the radially inner bottom surface is coplanar with the radially outer bottom surface.

22. The edge ring of claim 20, wherein a height of the pocket is seventy percent or less of the height of the edge ring.

23. The edge ring of claim 22, wherein the radially outer bottom surface comprises 20 to 24 pockets evenly spaced apart.

24. The edge ring of claim 20, wherein a length of the radially inner bottom surface defined between the radially inner groove and the radially outer groove is at least thirty- four percent of a total length of the edge ring.

25. The edge ring of claim 24, wherein the length of the radially inner bottom surface is in a range between thirty-five and thirty-eight percent of the total length of the edge ring.

26. The edge ring of claim 24, wherein the length of the radially inner bottom surface is at least fifty percent of the total length of the edge ring.

27. The edge ring of claim 26, wherein the length of the radially inner bottom surface is in a range between fifty-one and fifty-four percent of the total length of the edge ring.

28. The edge ring of claim 20, wherein the radially outer bottom surface is spaced apart from the radially inner bottom surface by an air gap.

29. The edge ring of claim 28, wherein a length of the air gap is in a range between ten percent and thirty percent of a length of the radially inner bottom surface defined between the radially inner groove and the radially outer groove.

30. The edge ring of claim 20, wherein: the radially inner groove is configured to retain a first O-ring; and the radially outer groove is configured to retain a second O-ring.

31 . The edge ring of claim 20, wherein a height of the radially inner groove is the same as a height of the radially outer groove.

32. The edge ring of claim 22, wherein: the height of the pocket is shorter than a height of a portion of the edge ring extending above the radially inner groove, the height of the pocket is taller than a height of the radially inner groove; and the height of the portion of the edge ring extending above the radially inner groove is less than the height of the edge ring.

33. The edge ring of claim 20, wherein the securing mechanism comprises a screw.