Plasma processing chamber lid cooling

Abstract

Semiconductor processing systems and system components for mitigating lid heating of a plasma processing chamber are described. A system includes a plasma-based processing chamber enclosing a processing region, the processing chamber including a first portion and a second portion, the first portion including sidewalls and a bottom, the second portion including a chamber lid; a substrate support within the processing chamber, the substrate support being configured to hold a first substrate within the processing region of the chamber; and a conductive structure proximate the chamber lid outside the processing chamber, the conductive structure forming a particular pattern including a heat transfer fluid pathway configured to circulate a heat transfer fluid through the conductive structure.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to plasma processing chamber lid cooling. BACKGROUND

[0002] This specification relates to semiconductor systems, processes, and apparatuses.

[0003] Plasma etching can be used in semiconductor processing to fabricate integrated circuits. Integrated circuits can be formed from a layered structure comprising a plurality of (e.g., two or more) layer compositions. Different etching gas chemistries, e.g., different gas mixture compositions, can be used to form a plasma in a processing environment, thereby providing a given etching gas chemistry with higher precision and higher selectivity to a layer composition to be etched. SUMMARY

[0004] This specification describes techniques for managing chamber lid temperature during plasma processing chamber operation of a plasma-based processing system. Plasma-based processing systems generate a plasma within a processing region to perform a particular processing procedure, e.g., plasma etching of a substrate supported in a processing chamber. In an inductively coupled plasma-based processing system, the processing chamber has a lid formed of a dielectric material that allows energy from an inductively coupled plasma source to pass through the lid into the plasma chamber. During plasma-based processing operations, the lid can experience heating. In particular, higher power applications, e.g., performing higher aspect ratio etching operations, can increase the amount of heating experienced by the lid. Excessive heating can result in damage to the chamber lid.

[0005] To reduce lid heating, techniques are provided for introducing a heat transfer fluid proximate to the chamber lid to provide cooling. In some implementations, a heat transfer fluid passage is formed within a Faraday shield structure positioned proximate to the chamber lid. In some implementations, the Faraday shield structure with the embedded fluid passage is positioned on the exterior (atmospheric side) of the chamber lid. In other implementations, the Faraday shield structure with the embedded fluid passage is positioned on the interior (vacuum side) of the chamber lid. Further, in some implementations, the fluid passage is embedded within a radio frequency induction coil of an inductively coupled plasma source. In other implementations, the fluid passage is formed within a block of dielectric material proximate to the chamber lid region.

[0006] In general, one innovative aspect of the subject matter described in this specification can be embodied in a system. The system includes a plasma-based processing chamber enclosing a processing region, the processing chamber including a first portion including a sidewall and a bottom and a second portion including a chamber lid; a substrate support within the processing chamber configured to hold a first substrate within the processing region of the chamber; and a conductive structure proximate the chamber lid on an exterior side of the processing chamber, the conductive structure forming a particular pattern, the pattern including a heat transfer fluid passage configured to circulate a heat transfer fluid through the conductive structure.

[0007] In general, another innovative aspect of the subject matter described in this specification can be embodied in a system. The system includes a plasma-based processing chamber enclosing a processing region, the processing chamber including a first portion including a sidewall and a bottom and a second portion including a chamber lid; a substrate support within the processing chamber configured to hold a first substrate within the processing region of the chamber; an inductively coupled plasma source configured to induct RF energy into the chamber; and a dielectric block proximate the chamber lid on an exterior side of the processing chamber, the dielectric block including a fluid passage configured to circulate a heat transfer fluid through the fluid passage of the dielectric block.

[0008] In general, another innovative aspect of the subject matter described in this specification can be embodied in a system. The system includes a plasma-based processing chamber enclosing a processing region, the processing chamber including a first portion including a sidewall and a bottom and a second portion including a chamber lid; a substrate support within the processing chamber configured to hold a first substrate within the processing region of the chamber; an inductively coupled plasma source configured to induct RF energy into the chamber; and a conductive structure proximate the chamber lid on an interior side of the processing chamber, the conductive structure including a heat transfer fluid passage configured to circulate a heat transfer fluid through the conductive structure having a particular pattern.

[0009] The subject matter described in this specification can be implemented in these and other specific embodiments so that one or more of the following advantages can be realized. Chamber lid heating is managed to maintain a consistent temperature or temperature range, reducing the risk of chamber lid damage from heat. In particular, as power levels increase, the use of fluid passages adjacent to the chamber lid can mitigate heat to a greater extent than cooling fans. Providing an increase in lid cooling capacity enables higher power etch processes, providing faster or deeper wafer etching. Embedded heat transfer fluid passages can supplement cooling provided by cooling fans, improving temperature management of the chamber lid. Faraday shields for lid heating electronics can be combined with fluid passages. In some embodiments, fluid passages are formed within a body of dielectric material to reduce electromagnetic interference with power supply power for a plasma processing chamber. Fluid passages can be positioned within structures within a plasma processing chamber that are disposed on an interior surface of a chamber lid. This enables both lid temperature management and space for other components outside the processing chamber.

[0010] While the remaining disclosure will describe the innovative technology in the context of a particular type of plasma-based processing chamber in which the disclosed technology is used, it will be readily understood that these systems and methods can be applicable to a variety of other types of plasma-based substrate processing chambers. Accordingly, this technology should not be considered to be so limited as only being used for the etch-based processes described. Prior to describing the systems and methods or operations of an exemplary process train in accordance with some embodiments of the technology, the present disclosure will discuss one possible system and chamber that can be used with the technology. It should be understood that the technology is not limited to the described apparatus, and the processes discussed can be performed in any number of processing chambers and systems. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 A cross-sectional schematic view of an example processing chamber is shown.

[0012] Figure 2A An isometric view of an example chamber lid and Faraday shield is shown.

[0013] Figure 2B An isometric view of another example Faraday shield is shown.

[0014] Figure 3 A cross-sectional schematic view of a portion of a processing chamber including a Faraday shield is shown. Figure 2A

[0015] Figure 4 An isometric view of a chamber lid and coil example is shown.

[0016] Figure 5A ​An isometric view showing a chamber lid and a recursive fluid passage example including a dielectric enclosure.

[0017] Figure 5B An isometric view showing a chamber lid and a recursive fluid passage example including a dielectric enclosure. Figure 5A An isometric view showing a chamber lid and a recursive fluid passage example including a dielectric enclosure.

[0018] Figure 6 An isometric view showing a Faraday shield example for performing vacuum side lid temperature management.

[0019] Figure 7 An isometric view showing a Faraday shield example for performing vacuum side lid temperature management coupled with a process chamber sidewall.

[0020] Figure 8 An isometric view showing a Faraday shield example for performing vacuum side lid temperature management coupled with a process chamber sidewall. Figure 7 A regional cutaway isometric view of a Faraday shield example illustrating embedded fluid passages.

[0021] Figure 9 A cross-sectional schematic view of a portion of a process chamber including a Faraday shield. Figure 6 A cross-sectional schematic view of a portion of a process chamber including a Faraday shield.

[0022] Figure 10 An example cross-sectional view of a Faraday shield edge portion.

[0023] Figure 11 An example cross-sectional view of a Faraday shield edge portion.

[0024] Like elements in the various figures are denoted by like reference numerals and designations. DETAILED DESCRIPTION

[0025] This specification describes techniques configured for managing plasma chamber lid heating during plasma processing operations. In some implementations, fluid passages are combined with Faraday shields to circulate heat transfer fluid. The heat transfer fluid can be used to absorb thermal energy from the chamber lid to provide cooling. In other implementations, fluid passages for circulating heat transfer fluid are combined with one or more inductively coupled plasma source coils. Further, in some implementations, fluid passages are formed within a block of dielectric material proximate to a chamber lid.

[0026] Figure 1A schematic cross-sectional view of an example processing chamber 100 suitable for etching one or more material layers disposed on a substrate 103 (also referred to as a "wafer") in the processing chamber 100 (e.g., a plasma processing chamber) is shown. The processing chamber 100 includes a chamber body 105 defining a chamber volume 101 in which a substrate can be processed. The chamber body 105 has a sidewall 112 and a bottom 118 coupled to a floor 126. The sidewall 112 can include a liner 115 to protect the sidewall 112 and extend the time between maintenance cycles of the plasma processing chamber 100. The chamber body 105 supports a chamber lid 110 to enclose the chamber volume 101. The chamber body 105 can be fabricated from, for example, aluminum or other suitable material. The chamber lid 110 can be formed of a dielectric material that allows energy from an inductively coupled plasma (ICP) source to pass through the chamber lid 110 to the processing volume 101. In some cases, the chamber lid 110 is referred to as a dielectric window.

[0027] A substrate access port 113 is formed through the sidewall 112 of the chamber body 105 to facilitate the transfer of the substrate 103 into and out of the plasma processing chamber 100. The access port 113 can be coupled to a transfer chamber and / or other chambers (not shown) of a substrate processing system, for example, for performing other processing on the substrate. A pumping port 145 is formed through the bottom 118 of the chamber body 105 and is coupled to the chamber volume 101. A pumping device can be coupled to the chamber volume 101 through the pumping port 145 to evacuate and control the pressure within the processing volume. The pumping device can include one or more vacuum pumps and throttle valves to output gases and processing byproducts to a foreline exhaust.

[0028] The chamber 100 can also include a lid heater 168 disposed on an outside of the chamber lid 110 opposite the chamber volume 101. In particular, the lid heater 168 can be positioned between the chamber lid 110 and the coil 148 of the inductively coupled plasma source. The lid heater 168 can be used to provide a set chamber temperature prior to initiating a plasma processing operation. In some implementations, the lid heater 168 includes or is proximate to a shield material, such as a Faraday shield, disposed between the lid heater 168 and the chamber lid 110. A Faraday shield is a layer of electrically conductive material, such as a metal like aluminum, that shields electromagnetic energy. The shield material can reduce the radio frequency coupling between the ICP source and the lid heater 168. The shielded lid heater 168 can be configured to have a particular shape with holes to couple energy from the ICP source to the chamber volume 101. In particular, without the shield, the electric power heating elements would interact with the electromagnetic field generated by the ICP source coil 148 and passing through the chamber lid 110. The shield prevents this interaction so that a plasma is accurately formed within the chamber volume 101 to perform a plasma processing operation.

[0029] In some embodiments, the heater 168 includes one or more heating elements, e.g., resistive heating elements, coupled to a power source (not shown) configured to provide sufficient energy to control the temperature of the heater 168, e.g., to control the temperature between 50 and 100 degrees Celsius. The heater 168 can be electrically grounded, e.g., to the sidewall of the chamber 100, or can be floating, e.g., can be positioned without being electrically coupled to ground. In addition, in some other embodiments as described below, the lid heater 168 can be a Faraday shield having one or more fluid passages circulating a heat transfer fluid. The circulating heat transfer fluid can be used to absorb excess heat from the lid.

[0030] The chamber volume 101 includes a processing region 107, e.g., a station for processing a substrate. A substrate support 135 can be disposed in the processing region 107 of the chamber volume 101 to support a substrate 103 during processing. The substrate support 135 can include an electrostatic chuck 122 for holding the substrate 103 during processing. The electrostatic chuck ("ESC") 122 can secure the substrate 103 to the substrate support 135 with electrostatic attraction. The ESC 122 can be powered by a radio frequency ("RF") power source 125 integrated with a matching circuit 124. The ESC 122 can include an electrode 121 embedded within a dielectric body. The electrode 121 can be coupled to the RF power source 125 and can provide a bias to attract plasma ions formed from processing gases in the chamber volume 101 to the ESC 122 and the substrate 103 positioned on the pedestal. The RF power source 125 can be cycled on and off, or pulsed, during processing of the substrate 103. The ESC 122 can have an isolator 128 to reduce the attraction of the sidewalls of the ESC 122 to the plasma to extend the maintenance life of the ESC 122. Additionally, the substrate support 135 can have a cathode liner 136 to protect the sidewalls of the substrate support 135 from the plasma gases and to extend the maintenance interval of the plasma processing chamber 100.

[0031] The electrodes 121 can be coupled to a DC power source 150. The power source 150 can provide an attraction voltage of about 200 volts to about 2000 volts to the electrodes 121. The power source 150 can also include a system controller for controlling the operation of the electrodes 121 by directing a direct current to the electrodes 121 for attraction and removal of the substrate 103. The ESC 122 can include a heater disposed within the ESC 122 and connected to the power source for heating the substrate, while a cooling base 129 supporting the ESC 122 can include conduits for circulating a heat transfer fluid to maintain the temperature of the ESC 122 and the substrate 103 disposed thereon. The ESC 122 can be configured to perform within a temperature range required by the thermal budget of the components being fabricated on the substrate 103. For example, depending on the process being performed, the ESC 122 can be configured to maintain the temperature of the substrate 103 within a range of about -150 °C or lower to about 500 °C or higher. A cover ring 130 can be disposed over the ESC 122 and along the periphery of the substrate support 135. The cover ring 130 can be configured to confine etching gas to a desired portion of the exposed top surface of the substrate 103 while shielding the top surface of the substrate support 135 from the plasma environment within the plasma processing chamber 100.

[0032] A gas panel 160 (also referred to herein as a "gas distribution manifold") can be coupled to the chamber body 105 through a gas line 167 through the chamber lid 110 for supplying process gas to the chamber volume 101. The gas panel 160 can include one or more process gas sources 161, 162, 163, 164, and can additionally include inert, non-reactive, and reactive gases as can be used for any number of suitable processing procedures. Examples of process gases that can be provided by the gas panel 160 include, but are not limited to, hydrocarbon-containing gases including methane, sulfur hexafluoride, silicon chloride, silicon tetrachloride, carbon tetrafluoride, hydrogen bromide. Process gases that can be provided by the gas panel can include, but are not limited to, argon, chlorine, nitrogen, helium, or oxygen, sulfur dioxide, and any number of additional materials. Further, the process gases can also include nitrogen, chlorine, fluorine, oxygen, or hydrogen-containing gases including, for example, BCl3, C2F4, C4F8, C4F6, CHF3, CH2F2, CH3F, NF3, NH3, CO2, SO2, CO, N2, NO2, N2O, and H2, as well as any number of additional suitable precursors. Process gases from the process gas sources (e.g., gas sources 161, 162, 163, 164) can be combined to form one or more etching gas mixtures. For example, the gas panel 160 includes one or more process gas sources dedicated to oxide-based etch chemistry. In another example, the gas panel 160 includes one or more process gas sources dedicated to nitride-based etch chemistry.

[0033] The gas panel 160 includes various valves and other components for controlling the flow of process gases from the sources. Valves 166 can control the outflow of process gases from the gas panel 160 from the sources 161, 162, 163, 164. The operation of the valves, pressure regulators, and / or mass flow controllers can be controlled by a controller 165. The controller 165 can be operatively coupled to an electrovalve (EV) manifold (not shown) to control the actuation of one or more valves, pressure regulators, and / or mass flow controllers.

[0034] The lid 110 can include a gas delivery nozzle 114. The gas delivery nozzle 114 can include one or more openings for introducing process gases from the sources 161, 162, 163, 164 of the gas panel 160 into the chamber volume 101. After the process gases are introduced into the plasma processing chamber 100, the gases can be energized to form a plasma. An antenna, such as one or more induction coils 148, can be disposed about the plasma processing chamber 100. An antenna power supply 142 can power the induction coils 148 through a matching circuit 141 to inductively couple energy, such as radio frequency energy, to the process gases to sustain a plasma formed from the process gases in the chamber volume 101 of the plasma processing chamber 100. The operation of the power supply 142 can be controlled by a controller, such as the controller 165, which can also control the operation of other components in the plasma processing chamber 100.

[0035] The controller 165 can be used to control the process sequence, regulate the flow of gases from the gas panel 160 into the plasma processing chamber 100, and other process parameters. Software routines, when executed by a computing device, such as one or more processors (for example, central processing units (CPUs)) having data communication with one or more memory storage devices, transform the computing device into a specific purpose computer, for example, a controller, that can control the plasma processing chamber 100 to perform processes in accordance with the present disclosure. The software routines can also be stored and / or executed by one or more other controllers that can be associated with the plasma processing chamber 100.

[0036] In some embodiments, at the end of a wafer etching process, an automated or semi-automated robotic manipulator (not shown) can be used to transfer the wafer from the substrate support out of the processing chamber, for example, through the substrate access port 113. For example, a robotic arm can transfer the wafer to another chamber (or another location) to perform another step in the manufacturing process.

[0037] Although described with respect to a plasma processing chamber, the present disclosure can be used in other processing chambers, such as a chemical vapor deposition (CVD) chamber, a physical vapor deposition (PVD) chamber, an atomic layer deposition (ALD) chamber, a thermal processing chamber, and the like. Figure 1The processing chamber is described as including a substrate support disposed within a processing region of a chamber volume, but two or more substrate supports can be disposed within a same chamber volume of respective processing regions, e.g., disposed within respective processing stations. For example, the processing chamber 100 can be a tandem processing chamber including two processing regions, each having a respective substrate support configured to retain a respective wafer during an etch process. The processing chamber 100 can include two or more processing regions within a chamber volume 101 to facilitate processing of two or more substrates in parallel within respective processing regions. The processing regions can be substantially isolated such that an etch process in a first processing region has minimal effect on an etch process in a second processing region, and vice versa.

[0038] Figure 2A An isometric view 200 of an example chamber lid 201 and Faraday shield 202 is shown. The chamber lid 201 can be formed from a single piece of dielectric material. For example, the chamber lid 201 can be formed from aluminum oxide (alumina Al203), quartz, or other suitable ceramic material such as yttrium oxide (yttria Y203). The chamber lid 201 can be shaped to form a vacuum seal with the sidewalls of a plasma processing chamber during operation. In some embodiments, the chamber lid 201 can include a lip configured to sit on one or more sidewall edges of a plasma processing chamber.

[0039] For example, the chamber lid 201 can be substantially disc-shaped, substantially forming a cylinder with a narrow height corresponding to the thickness 203 of the disc and the circular surfaces of the top and bottom faces. The diameter of the chamber lid 201 can be configured to be disposed on the end face of a cylindrical sidewall of a processing region of a plasma processing chamber. The circular surfaces include a vacuum side surface facing the interior region of the plasma processing chamber and an atmospheric side surface 205 facing outward away from the plasma processing chamber. In some embodiments, the chamber lid need not be disc-shaped. For example, depending on the design of the plasma processing chamber, the lid can be a rectangular solid or other geometric shape.

[0040] The thickness 203 of the disc-shaped chamber lid 201 can depend on the material used and the strength required, e.g., to withstand the low pressure plasma environment of the plasma processing chamber.

[0041] The chamber lid 201 generally includes an aperture 207 through which a gas delivery nozzle (not shown) is mounted for providing etching gas to the processing chamber. In other embodiments, the gas delivery structure can be integrated within the body of the chamber lid 201.

[0042] The Faraday shield 202 can have a spoke pattern extending radially around a top surface 205 of the chamber lid 201. The pattern is formed from segments of a return path that includes a number of first linear segments, such as first segment 212, extending from a first specified radius from a center point of the atmospheric side surface 205 to a second specified radius from the center point. The return path further includes a number of second linear segments, such as second segment 214, substantially perpendicular to the radius of the atmospheric side surface 205, and alternatingly coupled to the first linear segments at the first and second specified radii. The Faraday shield is formed from a suitable electrically conductive material, such as aluminum or copper.

[0043] The Faraday shield 202 includes a fluid passageway extending from an inlet point 208 through the return path to an outlet point 210. For example, the return path can be formed from a tubular metallic material having an inner diameter that defines the fluid passageway. The diameter of the fluid passageway can be selected according to a desired flow rate of a given heat transfer fluid, such as 1 gallon per minute.

[0044] To maintain a substantially constant temperature of the chamber lid 201 within a given processing chamber, or within a specified range of temperatures, a heat transfer fluid at a specified temperature is circulated through the fluid passageway inside the Faraday shield 202. The heat transfer fluid absorbs thermal energy from the chamber lid 201, thereby cooling the chamber lid 201. The heat transfer fluid can be selected according to specific performance parameters, such as operating capability and chemical stability within a specified temperature range. For example, the heat transfer fluid can be a fluorine-containing fluid, such as perfluoropolyether. In some embodiments, the heat transfer fluid entering the inlet point 208 is at zero degrees Celsius.

[0045] The heat transfer fluid exiting through the outlet port 210 can be delivered to a heat exchanger or chiller (not shown) to remove excess heat before the heat transfer fluid is recirculated through the Faraday shield 202. The temperature and flow rate of the heat transfer fluid entering the input port 208 can be controlled to achieve a specified amount of cooling. In particular, during operation of a plasma chamber, heating on the chamber lid 201 can increase, resulting in an adjustment of the heat transfer fluid.

[0046] The Faraday shield 202 can include one or more heating elements, such as resistive heating elements, driven by electrical power to provide initial heating of the chamber lid 201, such as to 80 to 90 degrees Celsius. The heating elements can be positioned at specified points along the return path of the Faraday shield 202. The heating elements can be coupled to an electrical power source. In some embodiments, each heating element can be independently controlled.

[0047] The lengths of the first and second segments of the gyration path can be different. For example, the spokes can be closer together or farther apart. In addition, the radial length of the first segment can vary from the spokes as a whole or from particular individual spokes, for example, to make some spokes longer than others. The particular geometry of the gyration path can be based on a combination of the geometry needed to provide substantially uniform temperature management to the chamber lid and the need for non-conductive through holes in the lid in order to pass energy from the ICP coil through the chamber lid 201 to the plasma processing chamber.

[0048] Figure 2B An isometric view 220 of another example Faraday shield 222 is shown. For convenience, the Faraday shield 222 is described with respect to a chamber lid 201 corresponding to the chamber lid of Figure 2A The Faraday shield 222 illustrates a Faraday shield applied to a smaller region of the chamber lid 201, for example, a central region, rather than extending substantially to the entire diameter of the chamber lid 201. Like the Faraday shield 202 in Figure 2A The Faraday shield 222 includes a fluid passageway extending from an inlet point 224 to an outlet point 226 through the gyration path. For example, the gyration path can be formed of a tubular metallic material having an inner diameter defining the fluid passageway. A more concentrated region containing the fluid passageway can be used to manage a higher level of heating to the central region of the chamber lid 201. The edge regions of the chamber lid can be cooled sufficiently, for example, by external cooling fans or conductively to the central region. The Faraday shield 222 can use less material for temperature management than the Faraday shield 202 in Figure 2A

[0049] While the gyration path is shown in the figures, other fluid path geometries can be used as long as the overall structure allows sufficient energy to pass through the conductive structure to form an operating plasma. For example, a "zig-zag" pattern or an inner ring with spokes radiating outward can be used. In addition, the fluid passageway can have different cross-sectional geometries, including circular and square.

[0050] In particular, heating can be more concentrated in the central region of the chamber lid 201, with a higher density of cooling passageways found in the center to provide uniform chamber lid 201 temperature control.

[0051] ​The Faraday shields 202, 222 can be fixed in position and in contact with the atmosphere side surface 205 of the chamber lid 201. For example, an adhesive or other attachment material can be used to fix the Faraday shields 202, 222 in position on the chamber lid 201. In other embodiments, a force can be applied to the Faraday shields 202, 222 to press the Faraday shields 202, 222 into contact with the chamber lid 201. For example, other components of the processing chamber can be coupled to the Faraday shields 202, 222 to provide a downward pressure toward the lid surface.

[0052] In some embodiments, a thermally conductive material is placed between the Faraday shields 202, 222 and the chamber lid 201. The thermally conductive material, such as a thermal gasket, can help provide a more uniform cooling distribution to the chamber lid 201. The thermally conductive material can be a graphite sheet or the like.

[0053] Figure 3 A schematic cross-sectional view 300 of a portion of a processing chamber 301 including a Faraday shield 202 is shown. Figure 2A The chamber lid 302 is positioned over a lip of a sidewall 304 of the processing chamber 301. A gas distribution nozzle 306 passes through a central aperture of the chamber lid 302 for providing and distributing etching gas to a processing volume 303 of the processing chamber 301. An ICP coil 308 is positioned for directing radio frequency energy through the chamber lid 302 and into the processing volume 303. The Faraday shield 202 is positioned on a surface of the chamber lid 302 and is coupled to a heat transfer fluid input line 310 and a heat transfer fluid output line 312.

[0054] In some embodiments, the heat transfer fluid can be circulated at a first temperature (e.g., 80 to 90 degrees Celsius) to initially heat the processing chamber or to maintain a temperature between plasma processing operations. During plasma processing operations, the heat transfer fluid can be switched to a heat transfer fluid maintained at a second temperature (e.g., zero degrees Celsius). In addition, a single circulating heat transfer fluid can also be temperature regulated, such as using a heat exchanger and / or chiller to switch the temperature of the heat transfer fluid. In some such embodiments, a separate electric lid heater is no longer needed. As a result, the Faraday shield can not be needed. The fluid passages can be formed of a non-conductive material, such as plastic.

[0055] Figure 4An isometric view 400 of an exemplary chamber lid 401, outer coil 402, and inner coil 404 is shown. The chamber lid 401 can be formed from a single piece of dielectric material. For example, the chamber lid 401 can be formed from aluminum oxide (aluminum oxide Al203), quartz, or other suitable ceramic material such as yttrium oxide (yttrium oxide Y203). The shape of the chamber lid 401 can form a vacuum seal with the sidewalls of a plasma processing chamber during operation. In some embodiments, the chamber lid 401 can include a lip configured to sit on one or more sidewall edges of a plasma processing chamber.

[0056] For example, the chamber lid 401 can be generally disc-shaped, substantially forming a cylinder with a narrow height corresponding to the thickness 403 of the disc and the top and bottom circular surfaces. The diameter of the chamber lid 401 can be configured to sit on the end face of a cylindrical sidewall of a processing region of a plasma processing chamber. The circular surfaces include a vacuum side surface facing toward the interior region of the plasma processing chamber and an atmospheric side surface 405 facing outward away from the plasma processing chamber.

[0057] The thickness 403 of the disc-shaped chamber lid 401 can depend on the material used and the strength required, for example, to withstand the low pressure plasma environment of a plasma processing chamber.

[0058] The chamber lid 401 includes an aperture 407 through which a gas delivery nozzle (not shown) is mounted for providing etching gas to the processing chamber. In other embodiments, the gas delivery structure can be integrated within the body of the chamber lid 401.

[0059] The outer coil 402 and the inner coil 404 each include internal fluid passages for circulating heat transfer fluid. The outer coil 402 is shown as three rows of flat coils or spirals that surround the outer region of the chamber lid 401. The outermost portion of the outer coil 402 is proximate to the outer edge of the atmospheric side surface 405. The innermost portion of the outer coil 402 is a specified radial distance from the center point of the chamber lid 401. The outer coil 402 includes an input port 406 that allows heat transfer fluid to enter the fluid passages of the outer coil 402 and an output port 408 that allows heat transfer fluid to exit the fluid passages of the outer coil 402. Each row of the outer coil 402 is spaced apart from one or more flat cable coils of an adjacent row.

[0060] Inner coil 406 is shown as three rows of flat coils or spirals that encircle the interior region of chamber lid 401. The innermost portion of inner coil 404 is a specified radial distance from the center point of chamber lid 401. The outermost portion of inner coil 404 is a specified radial distance from the innermost portion of outer coil 406. Thus, inner coil 406 and outer coil 404 are spaced apart. Inner coil 404 includes an input port 410 that allows passage of heat transfer fluid into the fluid passageway of outer coil 402 and an output port 412 that allows passage of heat transfer fluid out of the fluid passageway of outer coil 402. Each row of inner coil 404 is spaced apart from the adjacent row or rows of flat cable coils.

[0061] Inner coil 406 and outer coil 404 each have a thermally conductive material 414, 416 between the respective coil and chamber lid 401. The thermally conductive material, such as graphite sheet, has a high thermal conductivity to more evenly distribute the lid cooling. In some embodiments, only one of the coils includes a thermally conductive material, or neither of the coils includes a thermally conductive material.

[0062] Inner coil 406 and outer coil 404 can be made of a thermally conductive material as well as an electrically conductive material, such as copper or other suitable metal. In particular, in some embodiments, the coils also function as Faraday shields and can include one or more shielded electric heating elements.

[0063] The number of coils and the number of rows or windings per coil can vary depending on the particular application and cooling requirements. For example, inner coil 404 can include additional windings to provide greater cooling to the center region of the chamber lid, where the heating is greatest during plasma processing operations. Similarly, the spacing between each winding can vary depending on the amount of cooling required and the ability to deliver RF energy to the processing chamber.

[0064] The fluid passageway formed within each coil can have various cross-sectional shapes, including circular, rectangular, or other polygonal cross-sections. The cross-sectional diameter can depend on the properties of the heat transfer fluid and the specified flow rate to provide suitable heat transfer. The heat transfer fluid absorbs thermal energy from chamber lid 401 to cool chamber lid 401. For example, the heat transfer fluid can be ethylene glycol at a flow rate of one gallon per minute.

[0065] Inner coil 406 and outer coil 404 can each have a separate cooling loop. The heat transfer fluid that flows out of each output port can be delivered to a corresponding heat exchanger or chiller (not shown) to remove excess heat and then recirculated back to the corresponding coil.

[0066] In some embodiments, one or more of the coils can also function as ICP coils for the plasma processing system. Thus, the coils can be positioned above the chamber lid to function as vertical coils (e.g.,Figure 1 The coil 148 shown is different, as... Figure 4 One or more flat coils shown can be powered by a power source to generate radio frequency (RF) energy that enters the processing chamber. Therefore, while powering the coils to generate RF energy for the plasma chamber, a heat transfer fluid can flow within the internal passages of the coils. In some cases, the inner coil 404 serves only as an ICP coil, while the outer coil 402 serves only as a cooling coil. In other cases, the opposite is true. In other embodiments, both coils are powered. In some embodiments, the inner surface of the internal passages is coated with an insulating material.

[0067] Figure 5A An isometric view 500 is shown, including a chamber cover 502 with a dielectric housing and an example of a recursive fluid passage. Figure 5B Showing Figure 5A The example chamber cover 502 and the isometric view 501 of the recursive fluid passage are shown in the figure, with the top portion of the dielectric housing not visible.

[0068] Chamber cover 502 can be similar to about Figure 4 The chamber cover 401 is described above. A recursive cooling passage 504 is located in the central region of the atmospheric side surface of the chamber cover 502. The recursive fluid passage 504 includes an inlet port 508 and an outlet port 510 for circulating heat transfer fluid through the recursive fluid passage 504.

[0069] A recursive fluid passage 504 is located within a housing 506, which has a portion between the surface of the chamber cover 502 and the recursive fluid passage 504, and a cover portion 512 surrounding the other side of the recursive fluid passage 504. The housing 506 may be formed of a dielectric material such as aluminum nitride or other suitable ceramic material. Specifically, the housing 506 is formed of a material with appropriate thermal conductivity to adequately transfer heat from the chamber cover 502. As a dielectric material, it does not impede radio frequency energy from the ICP power source. The housing 506 may have a disk shape, with a central aperture for positioning gas delivery nozzles and other central components of the plasma processing system.

[0070] and Figure 4 Conversely, fluid passage 504 is located only in the central region of chamber cover 401, as the central region requires the greatest cooling. However, the recursive fluid passage can be extended with additional loops to cover a larger portion of the surface of chamber cover 502. Alternatively, separate recursive loops can be used in the external regions, similar to... Figure 4 The internal and external coils are shown.

[0071] In some implementations, the fluid passage 504 is formed within a solid housing body made of a dielectric material. For example, a first layer of dielectric material, such as aluminum nitride or other ceramic material, can be rolled to form a lower half of the fluid passage on a surface of the first layer; a second layer can be machined to form a mirror image of the upper half of the fluid passage on a surface of the second layer. The layers can then be joined together, e.g., with an adhesive layer and a sealant as appropriate, to form the fluid passage 504. In another example, the housing 506 can be built up layer by layer using an additive manufacturing technique, such as 3D printing, of aluminum nitride or other ceramic material. When the layers are 3D printed using an additive manufacturing technique, the fluid passage 504 can be formed as a single piece and enclosed within the housing 506.

[0072] In other implementations, the housing is formed of a separate dielectric material that surrounds the fluid passage 504. The recursive fluid passage 504 can be formed of a metallic material, such as copper or aluminum. Alternatively, the fluid passage 504 can be formed of a non-conductive material, such as plastic. The heat transfer fluid can be any suitable heat transfer fluid, such as perfluoropolyether or glycol, as described above. The heat transfer fluid can be selected and the recursive fluid passage, e.g., the cross-sectional diameter, can be defined to achieve a specified flow rate through the recursive cooling passage to provide a particular amount of heat transfer. For example, the recursive fluid passage 504 can be configured to circulate the heat transfer fluid at a flow rate of one gallon per minute at a specified temperature, such as zero degrees Celsius.

[0073] Figure 4 The chamber lid of FIGS. 5 can further include one or more lid heaters. For example, the lid heaters can be used to provide an initial baseline temperature for the processing chamber. In other implementations, the heat transfer fluid is used both to provide heating and to cool the chamber lid. In implementations with lid heaters, the lid heaters can be shielded, e.g., using a Faraday shield, to prevent interference with radio frequency source power.

[0074] Figure 6 An isometric view 600 of an example of a Faraday shield 602 for performing vacuum side lid temperature management is shown. Unlike the Faraday shields shown in FIGS. 2-5, the Faraday shield 602 is configured to be positioned on an inner surface of a chamber lid within a processing volume of a plasma processing chamber. The Faraday shield 602 includes an annular portion 604 and a spoke portion 606.

[0075] The configuration of the annular portion 604 enables the Faraday shield 602 to be coupled to a sidewall of a plasma processing chamber. The spoke portion 606 includes a plurality of individual spokes extending radially inward from the annular portion 604. As shown in FIG. 6, the Faraday shield 602 is configured to be positioned on an inner surface of a chamber lid 608 of a plasma processing chamber 610. Figure 6As shown, the spokes have different lengths and do not extend completely to the center region. Each spoke of the annular portion 604 and the spoke portion 606 has a certain width and height configured to provide fluid passageways 608 within the annular portion and each spoke while having sufficient strength to remain rigid within a low pressure plasma environment. In some embodiments, the Faraday shield 602 is further configured to provide structural support for a chamber lid of a plasma processing chamber.

[0076] In Figure 6 for ease of illustration, the fluid passageways 608 are exposed, although in a completed Faraday shield 602, the fluid passageways would be completely encased by the material of the Faraday shield 602. The fluid passageways 608 begin at a side input port 610 (shown in Figure 10 to 11 ) of the Faraday shield 602 and follow a path along the annular portion 604 to a first spoke in the spoke portion 606. The fluid passageway 608 passes through along one side of the spoke toward the center of the Faraday shield 602 and returns along a second side of the spoke. Then, the fluid passageway 608 is formed in the annular portion 606 until reaching the next spoke, where the path of each spoke is repeated until a side output port 612.

[0077] Figure 7 An isometric view of an example Faraday shield 602 for performing vacuum side lid temperature management coupled to a processing chamber sidewall 702 is shown. In particular, Figure 7 The annular portion 604 of the Faraday shield 602 coupled to the processing chamber sidewall 702 is shown. A chamber lid can sit atop the Faraday shield 602 to enclose a processing volume of a processing chamber, with the Faraday shield 602 on the inside of the chamber lid. In some embodiments, the height of the processing chamber sidewall 702 has been adjusted, e.g., shortened by the height of the Faraday shield 602, such that the distance between the chamber lid and a substrate in the processing chamber is the same as the distance between the chamber lid and the substrate in the processing chamber shown in FIG. 2.

[0078] During plasma processing operations in which the Faraday shield 602 is in surface contact with a chamber lid, a heat transfer fluid circulates through the fluid passageways 608 from the input port 610 to the output port 612 as described above with respect to FIG. 2 in order to provide cooling for the chamber lid. In particular, the Faraday shield 602 is in direct physical contact with portions of the chamber lid to provide thermal energy transfer from the lid to the heat transfer fluid.

[0079] Figure 8 An isometric view of an example Faraday shield 602 for performing vacuum side lid temperature management coupled to a processing chamber sidewall 702 is shown. In particular, Figure 6The figure shows an isometric view of a regional cross-sectional view 800 of an example Faraday shield 602, illustrating the embedded fluid passages. Regional cross-sectional view 800 shows a portion of the annulus and spokes of the Faraday shield 602. For clarity, a fluid passage 802 is illustrated, but it will be enclosed within the final Faraday shield structure. Furthermore, regional cross-sectional view 800 illustrates two additional annular channels in the annular portion of the Faraday shield 602. These annular channels provide conditions for specific sealing rings. A first annular channel 806 provides structural support for an RF gasket forming an RF barrier layer. A second annular channel 804 provides structural support for a sealing gasket (e.g., an O-ring) that protects the vacuum environment within the processing chamber by forming a seal between the Faraday shield 602 and the chamber cover.

[0080] Figure 9 Showing included Figure 6 A schematic cross-sectional view 900 shows a portion of the processing chamber 902 of the Faraday shield 602. The Faraday shield 602 is located on the lip of the sidewall 904 of the processing chamber 902. A chamber cover 906 is located on the Faraday shield 602. A gas distribution nozzle 908 passes through the central aperture of the chamber cover 906 to supply and distribute etching gas to the processing volume 901 of the processing chamber 902. Specifically, the gas distribution nozzle 908 enters the processing chamber 902 outside the Faraday shield 602. An ICP coil 910 is positioned to guide radio frequency energy through the chamber cover 906 and into the processing volume 901. The Faraday shield 602 is coupled to a heat transfer fluid inlet line 912 and a heat transfer fluid outlet line 914.

[0081] Figure 10 An example cross-sectional view 1000 shows an edge portion of the Faraday shield 1002. Specifically, Figure 10 A cross-section of the annular portion 1004 of the Faraday shield 1002 located at the input port 1016 of the heat transfer fluid passage 1008 is shown. The cross-sectional view 1000 includes a first annular channel 1012 for radio frequency sealing and a second annular channel 1010 for vacuum sealing (e.g., an O-ring). A horizontal passage 1014 couples the heat transfer fluid between the heat transfer fluid passage 1008 and the input port 1016.

[0082] like Figure 10 As shown, the narrow spacing between the annular channels 1010 and 1012 and the horizontal passage 1014 may, in some cases, introduce additional stress into the structure. Another structure is as follows... Figure 11 As shown.

[0083] Figure 11 An example cross-sectional view 1100 shows an edge portion of the Faraday shield 1102. Specifically, Figure 11A cross-section of the annular portion 1104 of the Faraday shield 1102 at the input port 1116 of the heat transfer fluid passage 1108 is shown. The cross-section view 1100 includes a first annular channel 1112 for radio frequency sealing and a second annular channel 1110 for vacuum sealing (e.g., O-ring). In Figure 11 In some embodiments, the angled passage 1114 couples the heat transfer fluid between the heat transfer fluid passage 1108 and the input port 1116. The angled passage 1114 is angled with respect to the plane of the Faraday shield 1102. This can allow for a larger separation between the angled passage 1114 and the annular channel, providing additional structural support for the Faraday shield 1102.

[0084] While this specification contains many specifics, these should not be construed as limitations on the scope of the claims which are determined by what is claimed, but by the claims themselves as required by law. Some features outside the literal scope of the claims can be described in this specification and can be performed by applicants in conjunction with the claimed features. Conversely, some features of the claimed features can be redundant from the perspective of a machine, but can be desirable for the human users or manufacturers. The claims should not be construed as limited to the features described in this specification, but should be construed to include any feature that, under the pre-AIA 35 U.S.C. 112, now 35 U.S.C. 101, would be

[0085] Also, although operations are depicted in the drawings in a particular order, this should not be understood as requiring such order, nor that all illustrated operations be performed, to achieve desirable results. In some circumstances, multitasking and parallel processing can be advantageous. Moreover, the separation of various system modules and components in the embodiments described above should not be understood as requiring such separation in all embodiments, it being generally understood that the described program components and systems can generally be integrated together as a software product or packaged into multiple software products.

[0086] Specific embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. For example, the operations recited in the claims can be performed in a different order and still achieve desirable results. As one example, the processes described in the figures do not necessarily require the particular order shown, or sequential execution, to achieve desirable results. In some circumstances, multitasking and parallel processing can be advantageous.

Claims

1. A system comprising: a plasma-based processing chamber enclosing a processing region, the processing chamber including a first portion comprising sidewalls and a bottom, and a second portion comprising a chamber lid; a substrate support within the processing chamber configured to hold a first substrate within the processing region of the chamber; and a conductive structure proximate the chamber lid on an exterior side of the processing chamber, the conductive structure forming a particular pattern, the pattern including a heat transfer fluid passageway configured to circulate a heat transfer fluid in the conductive structure.

2. The system of claim 1, wherein the conductive structure is a tubular passageway forming a fluid passageway shaped as a revolution path traversing a surface of the chamber lid.

3. The system of claim 2, wherein a diameter of the conductive structure is less than a chamber lid diameter such that the conductive structure overlaps only a central region of the chamber lid.

4. The system of claim 1, wherein the conductive structure is a flat coil, the flat coil having the fluid passageway formed within the body of the flat coil.

5. The system of claim 1, wherein the conductive structure includes a first flat coil and a second flat coil, the fluid passageway of each flat coil formed within the body of the respective first and second flat coils, the first flat coil embedded within the second flat coil and separated by a specified distance.

6. The system of claim 1, wherein the conductive structure further includes one or more electronic heaters, and wherein the conductive structure operates as a Faraday shield.

7. The system of claim 1, further comprising a thermally conductive material between the conductive structure and the chamber lid.

8. The system of claim 1, wherein the conductive structure is a flat coil, the flat coil having the fluid passageway formed within the body of the flat coil, and wherein the conductive structure is electrically coupled to a power source such that, when energized, the flat coil delivers radio frequency energy to the processing region of the processing chamber.

9. A system comprising: a plasma-based processing chamber enclosing a processing region, the processing chamber including a first portion comprising sidewalls and a bottom, and a second portion comprising a chamber lid; a substrate support within the processing chamber configured to hold a first substrate within the processing region of the chamber; an inductively coupled plasma source configured to induct radio frequency energy into the chamber; and a dielectric block proximate the chamber lid on an exterior side of the processing chamber, the dielectric block including a fluid passageway configured to circulate a heat transfer fluid through the fluid passageway of the dielectric block. ​ ​ 10. The system of claim 9, wherein the fluid pathway is a recursive path enclosed within the dielectric block.

11. The system of claim 9, wherein the dielectric block covers a central region of the chamber lid.

12. The system of claim 9, wherein the dielectric block and the fluid pathway are formed via additive manufacturing.

13. The system of claim 9, wherein the dielectric block can thermally conduct heat from the chamber lid to the circulating heat transfer fluid.

14. A system comprising: a plasma-based processing chamber enclosing a processing region, the processing chamber including a first portion including a sidewall and a bottom and a second portion including a chamber lid; a substrate support within the processing chamber and configured to hold a first substrate within the processing region of the chamber; an inductively coupled plasma source configured to induct radio frequency energy into the chamber; and a conductive structure on an interior side of the processing chamber proximate the chamber lid, the conductive structure including a heat transfer fluid pathway configured to circulate a heat transfer fluid through the conductive structure having a particular pattern.

15. The system of claim 14, wherein the conductive structure includes an annular portion and a spoke portion, the spoke portion including a plurality of individual spokes extending radially inward from the annular portion.

16. The system of claim 15, wherein the annular portion is configured to couple with the sidewall of the processing chamber.

17. The system of claim 16, wherein the chamber lid is positioned to enclose the processing chamber and, upon positioning, the chamber lid is in physical contact with the conductive structure.

18. The system of claim 14, wherein the fluid pathway begins at a side input port of the conductive structure, follows a path along the annular portion to a first spoke in the spoke portion, passes along one side of the first spoke toward the center of the conductive structure and returns along a second side of the first spoke, whereupon the fluid pathway is formed in the annular portion until reaching a second spoke, wherein the fluid path repeats for each spoke until ending at a side output port.

19. The system of claim 14, wherein the annular portion includes an inlet port and an outlet port, wherein the inlet port and the outlet port are coupled to the fluid pathway, allowing the heat transfer fluid to circulate in the fluid pathway.

20. The system of claim 19, wherein the fluid pathway is coupled to the inlet port through an angled path relative to a plane of the conductive structure through the annular portion. ​

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