Liquid Cooling Plate for Cooling the Dielectric Window of a Substrate Processing System

Abstract

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

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 349,745, filed Jun. 7, 2022. The entire disclosure of the above application is incorporated herein by reference.

[0002] The present disclosure relates to a substrate processing system, and more particularly, to a liquid cooling plate for cooling a dielectric window of a substrate processing system.

Background Art

[0003] The background description provided herein is for the purpose of generally presenting the content of the present disclosure. Within the scope described in this background art section, the research by the inventors named at the present time, as well as aspects of the description that cannot be separately considered as prior art at the time of filing, are not admitted as prior art against the present disclosure, whether explicitly or implicitly.

[0004] During the manufacture of a substrate such as a semiconductor wafer, a series of substrate processes such as deposition processes, etching processes, and / or cleaning processes are performed on the substrate. The substrate is typically delivered by a robot onto a substrate support such as an electrostatic chuck (ESC) or pedestal within a process chamber. Process gas is introduced into the process chamber via a gas distribution device, and plasma can be struck within the process chamber to facilitate a chemical reaction.

[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 adjacent to a dielectric window of the process chamber outside the process chamber. While process gas is being supplied into the process chamber, RF power is supplied to the induction coil. The induction coil generates a magnetic field within the process chamber, thereby igniting the plasma.

[0006] The dielectric window is heated during plasma processing. In some substrate processing systems, cold air is supplied to the entire dielectric window during plasma processing by using a cooling fan or an air amplifier including a plenum. The cooling fan and / or the air amplifier generate a large amount of noise and consume a significant amount of clean dry air (CDA). Further, the cooling fan or the air amplifier does not provide sufficient cooling for high-power processes. SUMMARY OF THE INVENTION

[0007] The substrate processing system includes a process chamber including a dielectric window and a substrate support. A gas delivery device is disposed within the process chamber between the dielectric window and the substrate support. An induction coil is disposed adjacent to the dielectric window outside the process chamber. 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 paths configured to flow the liquid coolant within N zones, where N is an integer greater than 1. The cooling plate includes a first portion including the N liquid flow paths and a second portion joined to the first portion to surround the N liquid flow paths. Opposing surfaces of the cooling plate and the dielectric window are in direct contact.

[0009] In other features, the first portion of the cooling plate including the N liquid flow paths is integrated with the dielectric window. The second portion is joined to the first portion to surround the N liquid flow paths. A thermal conduction layer is disposed between the cooling plate and the dielectric window. The thermal conduction layer includes silicone. The cooling plate is made of ceramic.

[0010] In other features, N temperature sensors are configured to each sense the temperature of N within the N zones. N valves are configured to each vary the supply of the liquid coolant to the N zones. A 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 each of the N heaters according to the N temperature sensors.

[0012] In other features, the induction coil includes N sets of coils. The N sets of coils are aligned with the N zones of the cooling plate. At least one of the N liquid flow paths is a bi-filar. At least one of the N liquid flow paths is a non-bi-filar.

[0013] A method for cooling a dielectric window of a substrate processing system is to provide a process chamber including a dielectric window, a substrate support, and a gas delivery device, wherein the gas delivery device is located between the dielectric window and the substrate support, to dispose an induction coil adjacent to the dielectric window outside the process chamber, to dispose a cooling plate between the induction coil and the dielectric window, and to flow a liquid coolant through the cooling plate.

[0014] In other features, the cooling plate includes N liquid flow paths configured to flow the liquid coolant within the N zones, where N is an integer greater than 1. The cooling plate includes a first portion including the N liquid flow paths and a second portion joined to the first portion. The opposing surfaces of the cooling plate and the dielectric window are in direct contact.

[0015] In other features, the first portion including the N liquid flow paths in the cooling plate is integrated with the dielectric window. The method includes surrounding the N liquid flow paths by joining the second portion to the first portion. The method includes disposing a heat conduction layer between the cooling plate and the dielectric window.

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

[0017] In other features, the induction coil includes N sets of coils, and further includes aligning each of the N sets of coils with the N zones of the cooling plate. At least one of the N liquid flow paths is a bi-filar. At least one of the N liquid flow paths is non-bi-filar.

[0018] 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 present disclosure.

Brief Description of the Drawings

[0019] The present disclosure will be more fully understood from the detailed description and the accompanying drawings.

[0020]

Figure 1A

[0021]

Figure 1B

[0022]

Figure 2

[0023]

Figure 3

[0024]

Figure 4A

[0025]

Figure 4B

[0026]

Figure 4C

[0027]

Figure 5

[0028] In the drawings, reference numbers may be reused to refer to similar and / or identical elements.

DETAILED DESCRIPTION OF THE INVENTION

[0029] When performing inductively coupled plasma (ICP) processing, the induction coil is disposed adjacent to the dielectric window of the process chamber outside the process chamber. The process gas is supplied into the process chamber through a shower head plate, a gas injector, or other gas delivery devices. An RF signal is supplied to the induction coil, thereby generating a magnetic field into the process chamber through the dielectric window. The magnetic field generates plasma by igniting the process gas. During substrate processing, the heat generated by the plasma and the induction coil (excited by the RF signal sent by the induction coil) raises the temperature of the dielectric window.

[0030] By controlling the temperature of the dielectric window and other components, mechanical stress can be minimized, thereby, for example, preventing damage or maintaining process uniformity. For example, an air plenum may be disposed above the dielectric window, and air circulation within the air plenum cools the dielectric window. In some processes, a relatively high air flow rate is required to sufficiently cool the dielectric window, resulting in an undesirable noise level. To reduce contamination, clean dry air (CDA) is typically used. As the plasma power increases, the temperature and mechanical stress also increase, and the cooling provided by the air flow can become insufficient.

[0031] The liquid cooling plate according to the present disclosure is disposed adjacent to (or integrated with) the dielectric window. The liquid cooling plate includes liquid flow paths disposed within two or more zones. The control system monitors the temperatures of the two or more zones and adjusts the liquid flow rate, liquid pressure, or liquid temperature supplied to the cooling plate.

[0032] Referring to FIGS. 1A and 1B, an example of a substrate processing system 100 including a liquid cooling plate is shown. The substrate processing system 100 includes a coil drive circuit 112. As shown, the coil drive circuit 112 includes an RF source 114 and a tuning circuit 116. The tuning circuit 116 may be directly connected to one or more induction coils 118. The tuning circuit 116 adjusts the output of the RF source 114 to a desired frequency and / or desired phase, matches the impedance of the induction coil 118, and optionally divides power between two or more sets of the induction coils 118 (when used). The liquid cooling plate 127 cools the dielectric window 126 by being disposed adjacent to 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 forms an internal plenum and a plurality of gas through-holes. The showerhead 124 is disposed between the dielectric window 126 and the substrate support 132. In some examples, the dielectric window 126 and the showerhead 124 are composed of ceramic or another dielectric material.

[0034] The substrate support 132 may include an electrostatic chuck (ESC), or a mechanical chuck or other types of chucks. In operation, the process gas is supplied to the process chamber 128 through the showerhead 124 (e.g., a plurality of holes through the gas plate), and the plasma 140 is generated inside the process chamber 128. For example, a magnetic field is sent through the dielectric window 126 by an 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. A bias can be applied to the substrate support 132 during the operation of controlling the ion energy using the RF source 150 and the bias matching circuit 152.

[0035] The gas delivery system 154 may be used to supply a process gas mixture to the process chamber 128. The gas delivery system 154 may include a process gas source and an inert gas source 156 (e.g., including deposition gas, etching gas, carrier gas, inert gas, etc.), valves 157, mass flow controllers 158, valves 159, and a manifold 160. The heater / cooler 162 may be used to heat / cool the substrate support 132 to a predetermined temperature. The exhaust system 164 includes valves 166 and a pump 168 to remove reactants by purging or discharging from the process chamber 128 and / or to control the pressure inside the process chamber.

[0036] The process may be controlled using the controller 170. The controller 170 monitors system parameters and controls the delivery of the gas mixture, the generation, maintenance, and extinction of the plasma, the removal of reactants, etc. Additionally, the controller 170 may control various aspects such as the coil drive circuit 112, the RF source 150, etc.

[0037] FIG. 1B shows an example of an induction coil 118 that 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 set of coils, or additional sets of coils may be used. In some examples, the liquid cooling plate 127 includes a plurality of zones. In some examples, the number of zones corresponds to the number of coils or the number of sets of coils.

[0038] Referring to FIG. 2, an example of a liquid cooling plate 127 and a control system 220 for supplying a cooling fluid to the liquid cooling plate 127 is shown. In this example, the liquid cooling plate 122 includes a first or inner zone including a coolant coil 210 and a second or outer zone including a coolant coil 212. Although two zones are shown in FIG. 2, additional zones may be used.

[0039] The chiller 230 supplies a cooling fluid to the coolant coil 212 in the second zone by providing cooled liquid to the valve 234-1 and the heater 236-1 via a conduit 235. In some examples, a bypass valve 240-1 is disposed between the chiller 230 and the valve 234-1. In other examples, the bypass valve 240-1 is omitted. The conduit 235 also supplies the cooling fluid to a second valve 234-2 and a second heater 236-2 that supply the coolant coil 210 in the first zone. In some examples, the valves 234-1 and 234-2 are variable valves that are controlled to vary the flow rate and / or pressure of the fluid. In some examples, the heaters 236-1 and 236-2 include resistive heaters.

[0040] In some examples, the temperature of the zones can be monitored. By arranging the temperature sensor 250, the temperature of the coolant coil 210 in the first zone is sensed. By arranging the temperature sensor 252, the temperature of the coolant coil 212 in the second zone is sensed. The controller 253 monitors the temperatures sensed by the temperature sensor 250 and the temperature sensor 252, and independently varies the flow rate and / or pressure of the liquid coolant flowing through the coolant coil 210 and / or the coolant coil 212 respectively by adjusting the valve 234-1 and the valve 234-2. The controller 253 also adjusts the power to the heaters 236-1 and 236-2 according to the sensed temperature.

[0041] Referring to FIG. 3, an example of a cooling coil for a liquid cooling plate including a plurality of zones is shown. In this example, the cooling coil 310 located in the first zone is a bifilar. The cooling coil 310 optionally includes an open central region 316. The cooling coil 312 located in the second zone is also a bifilar. In some examples, the cooling coil 310 and the cooling coil 312 include inlets and outlets arranged adjacent to each other radially outside the cooling coil 312. Although both the cooling coil 310 and the cooling coil 312 are shown as bifilars, one or both of them can be non-bifilars.

[0042] Now referring to FIGS. 4A and 4B, an example of a cooling plate 410 arranged above the dielectric window 440 is shown. The cooling plate 410 includes a cooling coil as described above. The cooling plate 410 is formed to include a liquid flow path in which the lower portion 416 is formed therein. The upper portion 414 surrounds the upper surface of the liquid flow path by being joined to the lower portion. In FIG. 4A, the bottom surface of the cooling plate 410 is in direct contact with the upper surface of the dielectric window 440.

[0043] In FIG. 4B, a thermal conduction layer 444 is optionally disposed between the bottom surface of the cooling plate 410 and the upper surface of the dielectric window 440, enabling heat transfer and relative movement. In some examples, the thermal conduction layer 444 can also be electrically insulating. In some examples, the thermal conduction layer 444 is made of silicone, although other materials can be used.

[0044] Referring now to FIG. 4C, an example of a liquid flow path within a liquid cooling plate is shown. The lower portion 416 includes a first liquid flow path 450 corresponding to a second zone and side walls 452 disposed between the first liquid flow paths 450 and / or between the second liquid flow paths 454. The lower portion 416 further includes a second liquid flow path 454 including side walls 456 disposed between the second liquid flow paths 454 and / or between the first liquid flow paths 450. The coolant flows separately through the first liquid flow path 450 and the second liquid flow path 454 to effect heat exchange with the dielectric window within the corresponding zones.

[0045] Referring now to FIG. 5, an example of an integrated cooling plate and dielectric window 510 is shown. The integrated cooling plate and dielectric window 510 includes a cooling coil as shown above. The integrated cooling plate and dielectric window 510 includes a first portion 516 in which a coolant flow path is formed. A second portion 518 of the integrated cooling plate and dielectric window 510 functions as a dielectric window. A third portion 514 is joined to the first portion 516 to surround the upper surface of the liquid flow path. Fabricating the cooling plate and the dielectric window using the same material means that the coefficients of thermal expansion (CTEs) of the cooling plate and the dielectric window match and exhibit similar responses when subjected to heating or cooling, thereby reducing mechanical stress.

[0046] As can be appreciated, by using a liquid-cooled plate instead of air cooling, the cooling performance of the dielectric window is significantly improved, enabling the use of higher power levels within the ICP chamber.

[0047] The foregoing description is merely illustrative in nature and is not intended to limit the present disclosure, its application, or its use. The broad teachings of the present disclosure can be implemented in a variety of forms. Accordingly, while the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited, because other variations will become apparent upon review of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method can be executed in a different order (or simultaneously) without changing the principles of the present disclosure. Further, while each embodiment has been described as having certain features, any one or more of those features described with respect to any embodiment of the present disclosure can be implemented in and / or combined with any of the features of any other embodiment, even if the combination is not explicitly described, provided that the combination is not mutually exclusive. In other words, the described embodiments are not mutually exclusive, and substitutions between one or more embodiments remain within the scope of the present disclosure.

[0048] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms including "connected," "engaged," "coupled," "adjacent," "next to," "on," "above," "below," and "disposed." Unless explicitly described as "direct," when a relationship between a first element and a second element is described in the above disclosure, the relationship can be a direct relationship in which no other intervening elements exist between the first and second elements, but can also be an indirect relationship in which one or more intervening elements exist (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, and the system may be part of the example described above. Such a system may include semiconductor processing equipment that includes one or more process tools, one or more chambers, one or more processing platforms, and / or certain processing components (such as a wafer pedestal, a gas flow system, etc.). These systems may be integrated with the electronic device to control the operation of the electronic device before, during, and after the processing of the semiconductor wafer or substrate. The electronic device may be referred to as a "controller" that can control various components or sub-parts of one or more systems. The controller may be programmed to control any of the processes disclosed herein, depending on the processing requirements and / or the type of system. Such processes include, but are not limited to, delivery of process gases, temperature setting (e.g., heating and / or cooling), pressure setting, vacuum setting, power setting, radio frequency (RF) generator setting, RF matching circuit setting, frequency setting, flow rate setting, fluid delivery setting, position and motion setting, loading and unloading of wafers to and from the tool, and loading and unloading of wafers to and from other transfer tools and / or load locks connected or coupled to a particular system.

[0050] Generally, a controller may be defined as an electronic device having various integrated circuits, logic, memory, and / or software that, for example, receive commands, issue commands, control operations, enable a cleaning operation, and enable endpoint measurement. The integrated circuits may include chips in the form of firmware that stores 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). The program instructions may be instructions transmitted to the controller in the form of various individual settings (or program files) that define operating parameters for performing a particular process on a semiconductor wafer or for a semiconductor wafer, or for the system. In some embodiments, the operating parameters may be part of a recipe defined by a process engineer to achieve one or more process steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or wafer dies.

[0051] In some implementations, the controller may be part of a computer integrated with, coupled to, or otherwise network-connected to the system, or may be coupled to such a computer, or may be a combination thereof. For example, the controller may be within the "cloud" or may be all or part of a fab host computer system, thereby enabling remote access to wafer processing. The computer may monitor the current progress of the fabrication operation, verify the history of past fabrication operations, verify trends or performance criteria from multiple fabrication operations, change the parameters of the current process, set the process steps following the current process, or initiate a new process by enabling remote access to the system. In some examples, a remote computer (e.g., a server) may provide a process recipe to the system through a network that may include a local network or the Internet. The remote computer may include a user interface that enables the input or programming of parameters and / or settings, which are then transmitted from the remote computer to the system. In some examples, the controller receives instructions in the form of data that specify the parameters of each process step to be executed during one or more operations. It should be understood that the parameters may be specific to the type of process being executed and the type of tool configured to be coupled or controlled by the controller. Thus, as described above, the controller may be distributed, such as by including one or more separate controllers network-connected to each other and operating towards a common purpose such as the processes and controls described herein. Examples of controllers distributed for such a purpose include one or more integrated circuits on a chamber that communicate with one or more integrated circuits remotely located (e.g., at the platform level or as part of a remote computer) to collaboratively control the process on the chamber.

[0052] Exemplary systems include, but are not limited to, a plasma etching chamber or module, a deposition chamber or module, a spin rinse chamber or module, a metal plating chamber or module, a cleaning chamber or module, a bevel edge etching 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 etching (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing system associated with or that can be used in the fabrication and / or manufacture of semiconductor wafers.

[0053] As described above, depending on one or more process steps performed by the tool, the controller can 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 the factory, a main computer, another controller, or a tool used for material transport to move a wafer container into and out of the tool position and / or load port within a semiconductor manufacturing facility.

Claims

1. A substrate processing system, comprising a process chamber including a dielectric window and a substrate support, a gas delivery device positioned between the dielectric window and the substrate support within the process chamber, an induction coil disposed adjacent to the dielectric window outside the process chamber, and a cooling plate disposed between the induction coil and the dielectric window and configured to flow a liquid coolant. A substrate processing system comprising the above.

2. The substrate processing system according to claim 1, wherein the cooling plate includes N liquid flow paths configured to flow the liquid coolant within N zones, and N is an integer greater than 1. A substrate processing system.

3. The substrate processing system according to claim 2, wherein the cooling plate includes a first portion including the N liquid flow paths and a second portion joined to the first portion to surround the N liquid flow paths. A substrate processing system.

4. The substrate processing system according to claim 2, wherein the opposing surfaces of the cooling plate and the dielectric window are in direct contact. A substrate processing system.

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

6. The substrate processing system according to claim 1, further comprising a heat conduction layer disposed between the cooling plate and the dielectric window. A substrate processing system.

7. The substrate processing system according to claim 6, wherein the heat conduction layer contains silicone, the substrate processing system.

8. The substrate processing system according to claim 1, wherein the cooling plate is made of ceramic, the substrate processing system.

9. The substrate processing system according to claim 2, further comprising N temperature sensors configured to respectively sense the temperatures of N in the N zones, the substrate processing system.

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 zones, the substrate processing system.

11. The substrate processing system according to claim 10, further comprising a controller configured to adjust the N valves according to the N temperature sensors, the substrate processing system.

12. The substrate processing system according to claim 9, further comprising N heaters configured to respectively selectively heat the liquid coolant delivered to the N zones, the substrate processing system.

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

14. The substrate processing system according to claim 2, wherein the induction coil includes N sets of coils, the N sets of coils are aligned with the N zones of the cooling plate, the substrate processing system.

15. The substrate processing system according to claim 2, wherein at least one of the N liquid channels is a bi-filer, the substrate processing system.

16. The substrate processing system according to claim 2, wherein at least one of the N liquid channels is a non-bi-filer, the substrate processing system.

17. A method for cooling a dielectric window of a substrate processing system, comprising providing a process chamber including a dielectric window, a substrate support, and a gas delivery device, wherein the gas delivery device is located between the dielectric window and the substrate support, arranging an induction coil adjacent to the dielectric window outside the process chamber, arranging a cooling plate between the induction coil and the dielectric window, flowing a liquid coolant through the cooling plate, the method comprising.

18. The method according to claim 17, wherein the cooling plate includes N liquid channels configured to flow the liquid coolant within N zones, N being an integer greater than 1, the method.

19. The method according to claim 18, wherein the cooling plate includes a first portion including the N liquid channels and a second portion joined to the first portion, the method.

20. The method according to claim 17, wherein the opposing surfaces of the cooling plate and the dielectric window are in direct contact, the method.

21. The method according to claim 18, wherein a first portion of the cooling plate including the N liquid channels is integrated with the dielectric window, A method further comprising surrounding the N liquid flow paths by joining a second part to the first part. **Claim 22** The method according to claim 17, further comprising disposing a heat conduction layer between the cooling plate and the dielectric window. **Claim 23** The method according to claim 17, wherein the cooling plate is made of ceramic. **Claim 24** The method according to claim 18, each sensing the N temperatures in the N zones; each varying the supply of the liquid coolant to the N zones according to the N temperatures; and further comprising. **Claim 25** The method according to claim 18, each sensing the N temperatures in the N zones; each selectively heating the liquid coolant delivered to the N zones according to the N temperatures; and further comprising. **Claim 26** The method according to claim 18, wherein the induction coil includes N sets of coils, and further comprising aligning each of the N sets of coils with the N zones of the cooling plate. **Claim 27** The method according to claim 18, wherein at least one of the N liquid flow paths is a bi-filar. **Claim 28** The method according to claim 18, wherein at least one of the N liquid flow paths is a non-bi-filar.

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