Liquid cooling plate for cooling dielectric window of substrate processing system

Abstract

A substrate processing system includes a processing chamber including a dielectric window and a substrate support. A gas delivery device is located within the processing chamber and between the dielectric window and the substrate support. An induction coil is disposed outside the processing chamber adjacent the dielectric window. A cooling plate is disposed between the induction coil and the dielectric window, and the cooling plate is configured to flow a liquid coolant.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 349,745, filed on June 7, 2022. The entire disclosure of the above application is incorporated herein by reference. Technical Field

[0002] The present disclosure relates to substrate processing systems, and more particularly to liquid cooling plates for cooling dielectric windows of substrate processing systems. Background Art

[0003] The background description provided here is for the purpose of generally presenting the background of the present disclosure. The work of the currently designated inventors within the scope described in this background section and aspects of the specification that were not determined to be prior art at the time of filing the application are neither explicitly nor implicitly admitted to be prior art against the present disclosure.

[0004] During the production of substrates (e.g., semiconductor wafers), a series of substrate processes, such as deposition, etching, and / or cleaning processes, are performed on the substrates. The substrate is usually transported by a robot to a substrate support, such as an electrostatic chuck (ESC) or a susceptor in a processing chamber. Process gases are introduced into the processing chamber through a gas distribution device, and plasma may be struck in the processing chamber to enhance chemical reactions.

[0005] In some examples, the process is an etching process, such as an inductively coupled plasma (ICP) process. In an ICP process, one or more induction coils are disposed outside the process chamber and adjacent to a dielectric window of the process chamber. When a process gas is supplied into the process chamber, RF power is applied to the induction coils. The induction coils generate a magnetic field within the process chamber that ignites a plasma.

[0006] Heating of the dielectric window occurs during plasma processing. In some substrate processing systems, cooling fans or air expanders containing plenums are used to provide cool air across the dielectric window during plasma processing. The cooling fans and / or air expanders make a lot of noise and consume a significant amount of clean dry air (CDA). In addition, the cooling fans or air expanders do not provide adequate cooling for high power processing. Summary of the invention

[0007] A substrate processing system includes: a processing chamber including a dielectric window and a substrate support. A gas delivery device is disposed in the processing chamber between the dielectric window and the substrate support. An induction coil is disposed outside the processing chamber and adjacent to the dielectric window. A cooling plate is disposed between the induction coil and the dielectric window and is configured to flow a liquid coolant.

[0008] In other features, the cooling plate includes N liquid flow channels configured to cool the liquid in N regions, where N is an integer greater than 1. The cooling plate includes: a first portion including the N liquid flow channels; and a second portion joined to the first portion to surround the N liquid flow channels. The cooling plate is in direct contact with the facing surface of the dielectric window.

[0009] In other features, a first portion of the cooling plate including the N liquid flow channels is integrated with the dielectric window. A second portion is bonded to the first portion to surround the N liquid flow channels. A thermally conductive layer is disposed between the cooling plate and the dielectric window. The thermally conductive layer includes silica gel. The cooling plate is made of ceramic.

[0010] In other features, the N temperature sensors are configured to sense N temperatures in the N zones, respectively. The N valves are configured to respectively change the supply of the liquid coolant to the N zones. The controller is configured to adjust the N valves in response to the N temperature sensors.

[0011] In other features, the N heaters are configured to selectively heat the liquid coolant delivered to the N zones, respectively. The controller is configured to adjust the N heaters, respectively, in response to the N temperature sensors.

[0012] In other features, the induction coil comprises N sets of coils. The N sets of coils are aligned with the N regions of the cooling plate. At least one of the N liquid flow channels is bifilar. At least one of the N liquid flow channels is non-bifilar.

[0013] A method for cooling a dielectric window of a substrate processing system comprises: providing a processing chamber comprising a dielectric window, a substrate support, and a gas delivery apparatus between the dielectric window and the substrate support; positioning an induction coil outside the processing chamber adjacent to the dielectric window; positioning a cooling plate between the induction coil and the dielectric window; and flowing a liquid coolant through the cooling plate.

[0014] In other features, the cooling plate includes N liquid flow channels configured to flow liquid coolant in N regions, where N is an integer greater than 1. The cooling plate includes: a first portion including the N liquid flow channels; and a second portion coupled to the first portion. The cooling plate is in direct contact with a facing surface of the dielectric window.

[0015] In other features, a first portion of the cooling plate including the N liquid flow channels is integrated with the dielectric window. The method includes: bonding a second portion to the first portion to surround the N liquid flow channels, and disposing a thermally conductive layer between the cooling plate and the dielectric window.

[0016] In other features, the cooling plate is made of ceramic. The method includes: sensing N temperatures in the N regions, respectively, and changing the supply of the liquid coolant to the N regions in response to the N temperatures. The method includes: sensing N temperatures in the N regions, respectively; and selectively heating the liquid coolant delivered to the N regions in response to the N temperatures, respectively.

[0017] In other features, the induction coil includes N sets of coils, and the N sets of coils are respectively directed to the N regions of the cooling plate. At least one of the N liquid flow channels is bifilar. At least one of the N liquid flow channels is non-bifilar.

[0018] Further scope of applicability of the present disclosure will become apparent from the detailed description, claims and 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

[0019] The present disclosure will be more fully understood from the detailed description and accompanying drawings, in which:

[0020] Figure 1A is a functional block diagram of an example of a substrate processing system including a liquid cooling plate for cooling a dielectric window of a processing chamber according to the present disclosure;

[0021] Figure 1B is an example of an induction coil comprising a set of inner coils and a set of outer coils;

[0022] Figure 2 A more detailed functional block diagram of an example of a liquid cooling plate including multiple zones and a control system for supplying cooling fluid to the cooling plate;

[0023] Figure 3 is a top view of an example of a liquid flow channel of a liquid cooling plate including multiple zones according to the present disclosure;

[0024] Figure 4A is a side view of an example of a cooling plate disposed above a dielectric window according to the present disclosure;

[0025] Figure 4B is a side view of an example of a cooling plate disposed above a thermal coupling layer and a dielectric window according to the present disclosure;

[0026] Figure 4C is a perspective view of an example of a liquid flow channel formed in a portion of the liquid cooling plate; and

[0027] Figure 5 is a side view of an example of a portion of a cooling plate (including multiple liquid flow channels) integrated with a dielectric window according to the present disclosure.

[0028] Among the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0029] When performing an inductively coupled plasma (ICP) process, an induction coil is disposed outside the process chamber adjacent to a dielectric window of the process chamber. Process gas is supplied to the process chamber via a showerhead plate, a gas injector, or other gas delivery device. An RF signal is supplied to the induction coil, which generates a magnetic field that passes through the dielectric window and into the process chamber. The magnetic field ignites the process gas to generate a plasma. During substrate processing, the heat generated by the plasma and the induction coil (excited by the RF signal delivered by the induction coil) increases the temperature of the dielectric window.

[0030] The temperature of the dielectric window and other components can be controlled to minimize mechanical stress, prevent damage, maintain process uniformity, etc. For example, an air plenum can be provided over the dielectric window, and air is circulated in the air plenum to cool the dielectric window. For some processes, relatively high air flows are required to provide adequate cooling of the dielectric window, which results in objectionable noise levels. To reduce contamination, a clean dry air system (CDA) is typically used. As plasma power increases, the temperature and mechanical stresses also increase, and the cooling provided by the air flow may be insufficient.

[0031] According to the present disclosure, a liquid cooling plate is disposed adjacent to (or integrated with) the dielectric window. The liquid cooling plate includes liquid flow channels disposed in two or more regions. A control system monitors the temperature of the two or more regions and adjusts the liquid flow, liquid pressure, or liquid temperature provided to the cooling plate.

[0032] See now Figure 1A and 1B , shows an example of a substrate processing system 100 that includes a liquid cooling plate. The substrate processing system 100 includes a coil drive circuit 112. As shown, the coil drive circuit 112 includes an RF power supply 114 and a tuning circuit 116. The tuning circuit 116 can be directly connected to one or more induction coils 118. The tuning circuit 116 tunes the output of the RF power supply 114 to a desired frequency and / or a desired phase, matches the impedance of the induction coil 118, and optionally distributes power between two or more groups of induction coils 118 (if used). A liquid cooling plate 127 is disposed adjacent to a dielectric window 126 to cool the dielectric window 126.

[0033] The substrate processing system 100 includes a showerhead 124 and a dielectric window 126. In some examples, the showerhead 124 includes a gas plate that defines an inner gas chamber and a plurality of gas through holes. The showerhead 124 is disposed between the dielectric window 126 and a substrate support 132. In some examples, the dielectric window 126 and the showerhead 124 are made of ceramic or other dielectric materials.

[0034] The substrate support 132 may include an electrostatic chuck (ESC), a mechanical chuck, or other types of chucks. In operation, a process gas is supplied to the process chamber 128 through the showerhead 124 (e.g., a plurality of holes through the gas plate), and a plasma 140 is generated within the process chamber 128. For example, a magnetic field is transmitted through the dielectric window 126 by the induction coil into the interior of the process chamber 128. The magnetic field excites gas molecules in the process chamber 128 to generate the plasma 140. The plasma 140 etches the exposed surface of the substrate 134. The RF power supply 150 and the bias matching circuit 152 can be used to bias the substrate support 132 during operation to control the ion energy.

[0035] A gas delivery system may be used to supply a process gas mixture to the process chamber 128. The gas delivery system may include: a process gas and inert gas source 156 (e.g., including deposition gas, etching gas, carrier gas, inert gas, etc.), a valve 157, a mass flow controller 158, a valve 159, and a manifold 160. A heater / cooler 162 may be used to heat / cool the substrate support 132 to a predetermined temperature. An exhaust system 164 includes: a valve 166 and a pump 168 to remove reactants from the process chamber 128 by purging or exhausting and / or to control the pressure in the process chamber.

[0036] A controller 170 may be used to control the process. The controller 170 monitors system parameters and controls the delivery of gas mixtures, striking, maintaining and extinguishing the plasma, removal of reactants, etc. Additionally, the controller 170 may control various aspects of the coil drive circuit 112, the RF power supply 150, etc.

[0037] Figure 1B , an example of the induction coil 118 is shown, which includes: a set of inner coils 190 and a set of outer coils 192. Although two sets of coils are shown, a single coil, a single coil group, or additional coil groups can be used. In some examples, the liquid cooling plate 127 includes multiple zones. In some examples, the number of zones corresponds to the number of coils or the number of coil groups.

[0038] Now refer to Figure 2, which shows an example of a liquid cooling plate 127 and a control system 220 for supplying cooling fluid to the liquid cooling plate 127. In this example, the liquid cooling plate 127 includes: a first or inner region, which includes a coolant coil 210; and a second or outer region, which includes a coolant coil 212. Although Figure 2 Two regions are shown, but additional regions may be used.

[0039] The cooler 230 provides cooling liquid to the valve 234-1 and the heater 236-1 via the conduit 235, thereby supplying cooling fluid to the coolant coil 212 of the second area. In some examples, the bypass valve 240-1 is disposed between the cooler 230 and the valve 234-1. In other examples, the bypass valve 240-1 is omitted. The conduit 235 also supplies the second valve 234-2 and the second heater 236-2, thereby supplying cooling liquid to the coolant coil 210 of the first area. In some examples, the valves 234-1 and 234-2 are variable valves that are controlled to change the fluid flow rate and / or pressure. In some examples, the heaters 236-1 and 236-2 include resistance heaters.

[0040] In some examples, the temperatures of these zones may be monitored. A temperature sensor 250 is configured to sense the temperature of the coolant coil 210 in the first zone; a temperature sensor 252 is configured to sense the temperature of the coolant coil 212 in the second zone; a controller 253 monitors the temperatures sensed by the temperature sensors 250 and 252, and adjusts valves 234-1 and 234-2 to independently change the flow rate and / or pressure of the liquid coolant flowing through the coolant coil 210 and / or the coolant coil 212; the controller 253 also adjusts the power to the heaters 236-1 and 236-2 in response to the detected temperatures.

[0041] Now refer to Figure 3 , which shows an example of cooling coils for a liquid cooling plate including multiple zones. In this example, the cooling coil 310 located in the first zone is bifilar. The cooling coil 310 optionally includes an open central zone 316. The cooling coil 312 located in the second zone is also bifilar. In some examples, the cooling coils 310 and 312 include an inlet and an outlet disposed adjacent to each other radially outside the cooling coil 312. Although both cooling coils 310 and 312 are shown as bifilar, one or both may also be non-bifilar.

[0042] Now refer to Figure 4A and 4B, which shows an example of a cooling plate 410 disposed above a dielectric window 440. The cooling plate 410 includes the cooling coil described above, and the cooling plate 410 is formed by a lower portion 416 that includes a liquid flow channel defined therein. An upper portion 414 is joined to the lower portion to surround the upper surface of the liquid flow channel. Figure 4A In the embodiment, the lower surface of the cooling plate 410 is in direct contact with the upper surface of the dielectric window 440 .

[0043] exist Figure 4B In some examples, a thermally conductive layer 444 is optionally disposed between the lower surface of the cooling plate 410 and the upper surface of the dielectric window 440 to allow heat transfer and relative movement. In some examples, the thermally conductive layer 444 may also be electrically insulating. In some examples, the thermally conductive layer 444 is made of silicone, but other materials may also be used.

[0044] Now refer to Figure 4C , which shows an example of a liquid flow channel in the liquid cooling plate. The lower portion 416 includes: a first liquid flow channel 450 corresponding to the second area; and a side wall 452, which is disposed between the first liquid flow channel 450 and / or the second liquid flow channel 454. The lower portion 416 also includes: a second liquid flow channel 454, which includes a side wall 456, which is disposed between the second liquid flow channel 454 and / or the first liquid flow channel 450. The cooling liquid flows through the first liquid flow channel 450 and the second liquid flow channel 454, respectively, to exchange heat with the dielectric window in the corresponding area.

[0045] Now refer to Figure 5 , which shows an example of an integrated cooling plate and dielectric window 510. The integrated cooling plate and dielectric window 510 includes the cooling coil described above. The integrated cooling plate and dielectric window 510 includes a first portion, the first portion 516 including a cooling liquid flow channel defined therein. The second portion 518 of the integrated cooling plate and dielectric window 510 serves as a dielectric window. A third portion 514 is bonded to the first portion 516 to surround the upper surface of the liquid flow channel. Using the same material to make the cooling plate and the dielectric window means that the coefficient of thermal expansion (CTE) of the cooling plate and the dielectric window are matched and behave similarly when exposed to heating or cooling, which can reduce mechanical stress.

[0046] As can be appreciated, the use of the liquid cooling plate, rather than air cooling, significantly improves the cooling performance of the dielectric window and allows higher power levels to be used in the ICP chamber.

[0047] The foregoing description is merely illustrative in nature and is by no means intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in various forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited, because when studying the drawings, the specification and the appended claims, other modifications will become apparent. It should be understood that, without changing the principles of the present disclosure, one or more steps in the method can be performed in different orders (or simultaneously). In addition, although each embodiment is described above as having certain features, any one or more of those features described relative to any embodiment of the present disclosure can be implemented in the features of any other embodiment and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the replacement of one or more embodiments with each other remains within the scope of the present disclosure.

[0048] Various terms are used to describe the spatial and functional relationships between elements (e.g., between modules, between circuit elements, between semiconductor layers, etc.), including "connected," "engaged," "coupled," "adjacent," "next to," "on top of," "above," "below," and "disposed." Unless the relationship between a first and a second element is explicitly described as "direct," when such a relationship is described in the above disclosure, the relationship can be a direct relationship, in which there are no other intervening elements between the first and second elements, but can also be an indirect relationship, in which there are one or more intervening elements (spatially or functionally) between the first and second elements. As used herein, the phrase "at least one of A, B, and C" should be interpreted to mean a logical (A or B or C), using a non-exclusive logical OR, and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C."

[0049] In some implementations, the controller is part of a system, which can be part of the above examples. Such a system can include a semiconductor processing device, which includes one or more processing tools, one or more chambers, one or more platforms for processing, and / or specific processing components (wafer pedestals, gas flow systems, etc.). These systems can be integrated with electronic devices for controlling their operation before, during, and after the processing of semiconductor wafers or substrates. The electronic device can be referred to as a "controller", which can control various components or subcomponents of one or more systems. Depending on the processing requirements and / or system type, the controller can be programmed to control any of the processes disclosed herein, including the delivery of process 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, position and operation settings, wafer transfer in and out of tools connected or docked with specific systems and other transfer tools and / or load locks.

[0050] In general, a controller can be defined as an electronic device having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operations, enable cleaning operations, enable endpoint measurements, etc. The integrated circuit can include a chip in the form of firmware that stores program instructions, a digital signal processor (DSP), a chip defined as an application specific integrated circuit (ASIC), and / or one or more microprocessors or microcontrollers that execute program instructions (e.g., software). The program instructions can be instructions sent to the controller in the form of various individual settings (or program files) that define operating parameters for performing specific processing on or for a semiconductor wafer or system. In some embodiments, the operating parameters can be part of a recipe defined by a process engineer to complete one or more processing steps during the manufacture of one or more (kinds of) layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0051] In some implementations, the controller may be 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 may be all or part of a wafer fab host system that may allow remote access to wafer processing. The computer may enable remote access to the system to monitor the current progress of a manufacturing operation, check the history of past manufacturing operations, check trends or performance criteria for multiple manufacturing operations, to change the parameters of the current processing, set processing steps to follow the current processing, or start a new processing. In some examples, a remote computer (e.g., a server) may provide a processing recipe to the system via a network (which may include a local network or the Internet). The remote computer may include a user interface that enables input or programming of parameters and / or settings, which are then sent from the remote computer to the system. In some examples, the controller receives instructions in the form of data that specify parameters for each processing step to be performed during one or more operations. It should be understood that the parameters may be specific to the type of processing 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, for example, by including one or more discrete controllers networked together and working toward a common purpose (e.g., processing and control as described herein). An example of a distributed controller for such a purpose is one or more integrated circuits on a chamber that communicate with one or more integrated circuits remotely (e.g., at a platform level or as part of a remote computer), which combine to control processing on the chamber.

[0052] Exemplary systems may include, but are not limited to, plasma etching chambers or modules, deposition chambers or modules, spin rinse chambers or modules, metal plating chambers or modules, cleaning chambers or modules, chamfer edge etching chambers or modules, physical vapor deposition (PVD) chambers or modules, chemical vapor deposition (CVD) chambers or modules, atomic layer deposition (ALD) chambers or modules, atomic layer etching (ALE) chambers or modules, ion implantation chambers or modules, track chambers or modules, and any other semiconductor processing system that may be associated with or used in the manufacture and / or preparation of semiconductor wafers.

[0053] As described above, depending on one or more processing steps to be performed by the tool, the controller can communicate with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout the factory, a host computer, another controller, or tools used in material transport to transport wafer containers to and from tool locations and / or load ports in a semiconductor manufacturing facility.

Claims

1. A substrate processing system, comprising: a processing chamber comprising a dielectric window and a substrate support; a gas delivery device located within the processing chamber between the dielectric window and the substrate support; An induction coil disposed outside the process chamber and adjacent to the dielectric window; and A cooling plate is disposed between the induction coil and the dielectric window and is configured to flow a liquid coolant. 2 . The substrate processing system of claim 1 , wherein the cooling plate comprises N liquid flow channels configured to flow the liquid coolant in N regions, wherein N is an integer greater than 1. 3 . 3 . The substrate processing system of claim 2 , wherein the cooling plate comprises: a first portion including the N liquid flow channels; and a second portion coupled to the first portion to surround the N liquid flow channels.

4. The substrate processing system of claim 2, wherein the cooling plate is in direct contact with a facing surface of the dielectric window.

5. The substrate processing system of claim 2, wherein a first portion of the cooling plate including the N liquid flow channels is integrated with the dielectric window, and the cooling plate further includes a second portion joined to the first portion to surround the N liquid flow channels.

6. The substrate processing system of claim 1, further comprising a thermally conductive layer disposed between the cooling plate and the dielectric window.

7. The substrate processing system of claim 6, wherein the thermally conductive layer comprises silicone.

8. The substrate processing system of claim 1, wherein the cooling plate is made of ceramic. 9 . The substrate processing system according to claim 2 , further comprising: N temperature sensors configured to sense N temperatures in the N regions, respectively.

10. The substrate processing system according to claim 9, further comprising: N valves configured to respectively change the supply of the liquid coolant to the N regions.

11. The substrate processing system of claim 10, further comprising: a controller configured to adjust the N valves in response to the N temperature sensors. 12 . The substrate processing system of claim 9 , further comprising: N heaters configured to selectively heat the liquid coolant delivered to the N zones, respectively.

13. The substrate processing system of claim 12, further comprising a controller configured to adjust the N heaters respectively in response to the N temperature sensors.

14. The substrate processing system of claim 2, wherein: The induction coil includes N groups of coils; and The N groups of coils are aligned with the N areas of the cooling plate.

15. The substrate processing system of claim 2, wherein at least one of the N liquid flow channels is double-line.

16. The substrate processing system of claim 2, wherein at least one of the N liquid flow channels is non-double-wire.

17. A method of cooling a dielectric window of a substrate processing system, the method comprising: providing a processing chamber comprising a dielectric window, a substrate support, and a gas delivery apparatus, the gas delivery apparatus being located between the dielectric window and the substrate support; disposing an induction coil outside the process chamber and adjacent to the dielectric window; placing a cooling plate between the induction coil and the dielectric window; as well as A liquid coolant is flowed through the cooling plate. 18 . The method of claim 17 , wherein the cooling plate comprises N liquid flow channels configured to flow the liquid coolant in N regions, wherein N is an integer greater than 1.

19. The method of claim 18, wherein the cooling plate comprises: a first portion comprising the N liquid flow channels; and a second portion coupled to the first portion.

20. The method of claim 17, wherein the cooling plate is in direct contact with a facing surface of the dielectric window.

21. The method of claim 18, wherein a first portion of the cooling plate containing the N liquid flow channels is integrated with the dielectric window, and the method further comprises bonding a second portion to the first portion to surround the N liquid flow channels.

22. The method of claim 17, further comprising disposing a thermally conductive layer between the cooling plate and the dielectric window.

23. The method of claim 17, wherein the cooling plate is made of ceramic.

24. The method of claim 18, further comprising: sensing N temperatures in the N regions, respectively; and In response to the N temperatures, supply of the liquid coolant to the N regions is changed respectively.

25. The method of claim 18, further comprising: sensing N temperatures in the N regions respectively; and In response to the N temperatures, the liquid coolant delivered to the N zones is selectively heated, respectively.

26. The method of claim 18, wherein the induction coil comprises N sets of coils, and further comprising aligning the N sets of coils to the N regions of the cooling plate, respectively.

27. The method of claim 18, wherein at least one of the N liquid flow channels is double-wire.

28. The method of claim 18, wherein at least one of the N liquid flow channels is non-bilinear.

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