Temperature control device and substrate processing apparatus

Abstract

This invention provides a temperature control device and a substrate processing device that can reduce energy loss caused by maintaining the temperature of a heat transfer medium with a large temperature difference. The temperature control device of this invention includes: a first tank for storing a first heat transfer medium; a second tank for storing a second heat transfer medium with a temperature different from that of the first heat transfer medium; and a first connecting pipe that connects the upper limit of the liquid level in the first tank to the lower limit of the liquid level in the second tank.

Description

[Technical Field]

[0001] This invention relates to a temperature control device and a substrate processing device. [Previous Technology]

[0002] In substrate processing apparatuses, coolers are sometimes used to control temperature by pumping high-temperature and low-temperature heat transfer media into flow paths within a mounting stage and circulating them. Regarding this type of cooler, a solution has been proposed that uses tanks for storing heat transfer media on both the high-temperature and low-temperature sides, and that a liquid level adjustment tank connects the high-temperature tank and the low-temperature tank to control the liquid level (Patent Document 1). Furthermore, a solution has been proposed that connect the high-temperature and low-temperature tanks using a passive leveling connecting pipe with the same liquid level (Patent Document 2). [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] U.S. Patent Application Publication No. 2014 / 0262199 [Patent Document 2] U.S. Patent Application Publication No. 2015 / 0316941 [Summary of the Invention]

[0004] [The problem the invention aims to solve]

[0005] This invention provides a temperature control device and a substrate processing device that can reduce energy loss caused by maintaining the temperature of a heat transfer medium with a large temperature difference. [Technical Means for Solving the Problem]

[0006] One embodiment of the temperature control device of the present invention comprises: a first tank for storing a first heat medium; a second tank for storing a second heat medium with a temperature different from that of the first heat medium; and a first connecting pipe connecting the upper limit of the liquid level in the first tank to the lower limit of the liquid level in the second tank. [Effects of the Invention]

[0007] According to the present invention, energy loss caused by maintaining the temperature of a heat medium with a large temperature difference can be reduced.

Implementation Method

[0009] Hereinafter, embodiments of the disclosed temperature control device and substrate processing device will be described in detail based on the drawings. Furthermore, the disclosed technology is not limited to the following embodiments.

[0010] When heat transfer fluid is stored in tanks on the high-temperature side and the low-temperature side respectively, it is necessary to control the liquid level in the tanks within a suitable range in order to prevent overflow of the heat transfer fluid or pump idling due to insufficient liquid volume. Therefore, the bottoms and tops of the tanks are connected to each other by connecting pipes, so that the heat transfer fluid and gas in each tank can flow back and forth. However, when connecting tanks with large temperature differences by connecting pipes, whenever the return circulation volume is uneven, the heat transfer fluid will move to make the liquid level align, so a large energy loss will continue to occur in order to maintain the temperature of the heat transfer fluid at the set temperature. Furthermore, the main factors that cause uneven return circulation volume include, for example, volume changes caused by temperature changes of the heat transfer fluid, the switching action of check valves or valves, evaporation of the heat transfer fluid in the high-temperature side tank and liquefaction in the low-temperature side tank, and pulsation of the circulation pump. Therefore, it is desirable to reduce energy loss caused by maintaining the temperature of the heat medium with a large temperature difference in the tanks connected by connecting pipes.

[0011] [Configuration of Substrate Processing Apparatus 1] FIG1 is a schematic cross-sectional view showing an example of a substrate processing apparatus according to one embodiment of the present invention. The substrate processing apparatus 1 is, for example, a plasma etching apparatus having parallel plate electrodes. The substrate processing apparatus 1 includes an apparatus body 10 and a control device 11. The apparatus body 10 is made of, for example, a material such as aluminum, and has a processing container 12 having, for example, a generally cylindrical shape. The inner wall surface of the processing container 12 is anodized. Furthermore, the processing container 12 is safely grounded.

[0012] A generally cylindrical support portion 14 made of an insulating material such as quartz is provided on the bottom of the processing container 12. The support portion 14 extends from the bottom of the processing container 12 in a vertical direction (for example, toward the upper electrode 30) inside the processing container 12.

[0013] A stage PD is provided inside the processing container 12. The stage PD is supported by a support 14. The stage PD holds a wafer W on its upper surface. The wafer W is an example of a temperature-controlled object. The stage PD has an electrostatic chuck ESC and a lower electrode LE. The lower electrode LE is made of a metal material such as aluminum and has a generally disk-shaped form. The electrostatic chuck ESC is disposed on the lower electrode LE. The lower electrode LE is an example of a heat exchange component that exchanges heat with the temperature-controlled object.

[0014] The electrostatic chuck ESC has a structure in which an electrode EL, which serves as a conductive film, is disposed between a pair of insulating layers or a pair of insulating sheets. The electrode EL is electrically connected to a DC power supply 17 via a switch SW. The electrostatic chuck ESC uses electrostatic forces, such as Coulomb force, generated by the DC voltage supplied from the DC power supply 17 to attract the wafer W to the upper surface of the electrostatic chuck ESC. In this way, the electrostatic chuck ESC can hold the wafer W.

[0015] A heat transfer gas, such as He gas, is supplied to the electrostatic chuck ESC via piping 19. The heat transfer gas supplied via piping 19 is supplied between the electrostatic chuck ESC and the wafer W. The thermal conductivity between the electrostatic chuck ESC and the wafer W can be adjusted by adjusting the pressure of the heat transfer gas supplied between the electrostatic chuck ESC and the wafer W.

[0016] Furthermore, a heater HT, serving as a heating element, is provided inside the electrostatic chuck ESC. The heater HT is connected to a heater power supply HP. By supplying power from the heater power supply HP to the heater HT, the wafer W on the electrostatic chuck ESC can be heated via the electrostatic chuck ESC. The temperature of the wafer W placed on the electrostatic chuck ESC is adjusted by the lower electrode LE and the heater HT. Alternatively, the heater HT can also be positioned between the electrostatic chuck ESC and the lower electrode LE.

[0017] An edge ring ER is arranged around the electrostatic chuck ESC, surrounding the edge of the wafer W and the electrostatic chuck ESC. The edge ring ER is also called a focusing ring. The edge ring ER can improve the in-plane uniformity of the processing of the wafer W. The edge ring ER is made of a material such as quartz, which is appropriately selected according to the material of the film to be etched.

[0018] Inside the lower electrode LE, a flow path 15 is formed for the flow of a heat transfer medium, such as Galden (registered trademark), as an insulating fluid. Furthermore, the heat transfer medium is sometimes expressed as brine. The flow path 15 is connected to a temperature control device 20 via pipes 16a and 16b. The temperature control device 20 controls the temperature of the heat transfer medium flowing within the flow path 15 of the lower electrode LE. The heat transfer medium, whose temperature is controlled by the temperature control device 20, is supplied to the flow path 15 of the lower electrode LE via pipe 16a. The heat transfer medium flowing within the flow path 15 flows back to the temperature control device 20 via pipe 16b.

[0019] The temperature control device 20 circulates the heat medium flowing within the flow path 15 of the lower electrode LE. Furthermore, the temperature control device 20 mixes a heat medium of a first temperature or a heat medium of a second temperature with the circulating heat medium and supplies it into the flow path 15 of the lower electrode LE. By mixing the heat medium of the first temperature or the heat medium of the second temperature with the circulating heat medium and supplying it into the flow path 15 of the lower electrode LE, the temperature of the lower electrode LE is controlled to a set temperature. The first temperature is, for example, a temperature above room temperature, and the second temperature is, for example, a temperature below 0°C. Hereinafter, the heat medium of the first temperature will be referred to as the first heat medium, and the heat medium of the second temperature will be referred to as the second heat medium. The first heat medium and the second heat medium are fluids with different temperatures but the same material. The temperature control device 20 and the control device 11 are examples of heat medium control devices.

[0020] A power supply tube 69 for supplying high-frequency power to the lower electrode LE is electrically connected to the lower surface of the lower electrode LE. The power supply tube 69 contains metal. Also, although not shown in FIG1, a lifting pin or its drive mechanism for transferring the wafer W on the electrostatic chuck ESC is disposed in the space between the lower electrode LE and the bottom of the processing container 12.

[0021] The feed tube 69 is connected to the first high-frequency power supply 64 via the matching circuit 68. The first high-frequency power supply 64 generates high-frequency power, i.e., high-frequency bias power, for feeding ions into the wafer W, for example, generating high-frequency bias power with a frequency of 400 kHz to 40.68 MHz, and in one example, a frequency of 13.56 MHz. The matching circuit 68 is a circuit used to match the output impedance of the first high-frequency power supply 64 with the input impedance on the load (lower electrode LE) side. The high-frequency bias power generated by the first high-frequency power supply 64 is supplied to the lower electrode LE via the matching circuit 68 and the feed tube 69.

[0022] An upper electrode 30 is disposed above the stage PD and opposite to the stage PD. A lower electrode LE is configured to be substantially parallel to the upper electrode 30. Plasma is generated in the space between the upper electrode 30 and the lower electrode LE, and plasma processing such as etching is performed on the wafer W held on the upper surface of the electrostatic chuck ESC by the generated plasma. The space between the upper electrode 30 and the lower electrode LE is the processing space PS.

[0023] The upper electrode 30 is supported on the upper part of the processing container 12, for example, through an insulating shielding member 32 containing quartz or the like. The upper electrode 30 has an electrode plate 34 and an electrode support 36. The lower surface of the electrode plate 34 faces the processing space PS. A plurality of gas outlets 34a are formed on the electrode plate 34. The electrode plate 34 is, for example, made of a silicon-containing material.

[0024] The electrode support 36 is made of a conductive material such as aluminum and supports the electrode plate 34 from above, allowing it to be easily installed and removed. The electrode support 36 may have a water-cooling structure (not shown). A diffusion chamber 36a is formed inside the electrode support 36. A plurality of gas outlets 36b, communicating with the gas outlet 34a of the electrode plate 34, extend downward from the diffusion chamber 36a (towards the stage PD). A gas inlet 36c is provided in the electrode support 36 to introduce processing gas into the diffusion chamber 36a, and the gas inlet 36c is connected to a piping 38.

[0025] Piping 38 is connected to gas source group 40 via valve group 42 and flow controller group 44. Gas source group 40 has a plurality of gas sources. Valve group 42 contains a plurality of valves, and flow controller group 44 contains a plurality of flow controllers such as mass flow controllers. Each of the gas sources 40 is connected to piping 38 via a corresponding valve in valve group 42 and a corresponding flow controller in flow controller group 44.

[0026] Accordingly, the device body 10 can supply processing gas from one or more selected gas sources in the gas source group 40 at individually adjusted flow rates to the diffusion chamber 36a within the electrode support 36. The processing gas supplied to the diffusion chamber 36a diffuses within the diffusion chamber 36a and is supplied in a cluster pattern to the processing space PS via various gas inlets 36b and gas outlets 34a.

[0027] The electrode support 36 is connected to the second high-frequency power supply 62 via a matching adapter 66. The second high-frequency power supply 62 is a power source that generates high-frequency power for plasma generation, for example, generating high-frequency power with a frequency of 27 to 100 MHz, and in one example, a frequency of 60 MHz. The matching adapter 66 is a circuit used to match the output impedance of the second high-frequency power supply 62 with the input impedance on the load side (upper electrode 30). The high-frequency power generated by the second high-frequency power supply 62 is supplied to the upper electrode 30 via the matching adapter 66. Furthermore, the second high-frequency power supply 62 can also be connected to the lower electrode LE via the matching adapter 66.

[0028] An accumulation mask 46, coated with Y2O3 or quartz and containing aluminum, is detachably provided on the inner wall of the processing container 12 and the outer side of the support 14. The accumulation mask 46 prevents etching byproducts (accumulations) from adhering to the processing container 12 and the support 14.

[0029] An exhaust plate 48, coated with Y2O3 or quartz and containing aluminum, is provided between the outer sidewall of the support portion 14 and the inner sidewall of the processing container 12, and on the bottom side of the processing container 12 (the side where the support portion 14 is provided). An exhaust port 12e is provided below the exhaust plate 48. The exhaust port 12e is connected to the exhaust device 50 via an exhaust pipe 52.

[0030] The exhaust device 50 is equipped with a vacuum pump such as a turbomolecular pump, which can reduce the pressure of the space inside the processing container 12 to the required vacuum level. An opening 12g for moving the wafer W into or out is provided on the side wall of the processing container 12. The opening 12g can be opened and closed by a gate valve 54.

[0031] The control device 11 includes a processor, memory, and an input / output interface. The memory stores programs executed by the processor and recipes containing conditions for each process. The processor executes the program read from the memory, and based on the recipes stored in the memory, controls various parts of the device body 10 via the input / output interface, thereby performing specific processes such as etching on the wafer W. The control device 11 is an example of a control unit.

[0032] [Configuration of Temperature Control Device 20] FIG2 is a diagram showing an example of the temperature control device of this embodiment. The temperature control device 20 includes a circulation section 200, a first temperature control section 220, and a second temperature control section 240. Furthermore, for example, the circulation section 200 is provided at the same level as the level where the processing container 12 is provided, and the first temperature control section 220 and the second temperature control section 240 are provided at a level lower than the circulation section 200.

[0033] In the circulation section 200, the outlet side of valve 201 is connected to pipe 16a. Furthermore, in the circulation section 200, a pump 202, which circulates the heat medium flowing within the flow path 15 of the lower electrode LE, is connected to pipe 16b. Pipe 16b at the outlet side of pump 202 is connected to the inlet side of valve 201 via check valve 206 at connection position A and pipe 207. Because the pressure in pipe 207 is lower than the pressure in pipe 16b at the outlet side of pump 202 during pump 202 operation, check valve 206 opens. Therefore, the heat medium circulates in the path of pump 202, pipe 16b, check valve 206, pipe 207, valve 201, pipe 16a, flow path 15, and pipe 16b. Furthermore, pipe 207 is an example of a third pipe. Furthermore, a temperature sensor 203 for detecting the temperature at the inlet side of the flow path 15 is provided in the piping 16a within the circulation section 200. Alternatively, the temperature sensor 203 can be located outside the temperature control device 20. For example, the temperature sensor 203 can be located directly below the lower electrode LE, such as at the connection between the piping 16a and the flow path 15, or it can be located between the lower electrode LE and the temperature control device 20.

[0034] The first temperature control unit 220 is connected to pipe 16a via pipe 229, pipe 210, and valve 201. Furthermore, the first temperature control unit 220 is connected to pipe 16b via pipe 230, pipe 212, and check valve 204. Moreover, the connection point B between pipe 229 and pipe 210 and the connection point C between pipe 230 and pipe 212 are connected via pipe 211, which serves as a bypass pipe. Furthermore, a monitoring pressure sensor 208 is provided at connection point C.

[0035] In this embodiment, the first temperature control unit 220 controls the temperature of the first heat medium. The first temperature control unit 220 mixes the temperature-controlled first heat medium with the heat medium circulating from pipe 207 to pipe 16a via pipe 229, pipe 210 and valve 201, and supplies it to the flow path 15 of the lower electrode LE. The temperature of the first heat medium is higher than the temperature of the second heat medium, for example, it can be set to 90°C. Furthermore, the temperature of the first heat medium can be any temperature as long as it is higher than the temperature of the second heat medium. The pressure in pipes 210-212, 229 and 230 is reduced due to the supply of the first heat medium to the flow path 15 of the lower electrode LE. Then, a portion of the heat medium discharged from the flow path 15 flows back to the first temperature control unit 220 at the connection position A of pipe 16b through the check valve 204 opened due to the pressure reduction, via pipes 212 and pipe 230. The piping including pipes 229, 210, and 16a is an example of a supply piping or a first supply piping. Also, the piping including pipes 16b, 212, and 230 is an example of a return piping or a first return piping. Furthermore, the piping including pipes 210-212, 229, and 230 is an example of a first piping.

[0036] In the first temperature control unit 220, a pump 222 supplies heat medium from the storage tank 221 to the piping 229. Furthermore, a heat exchanger 223, a flow sensor 224, a pressure sensor 225, a temperature sensor 226, and a variable valve 227 are provided on the outlet side of the pump 222. That is, the heat exchanger 223, flow sensor 224, pressure sensor 225, temperature sensor 226, and variable valve 227 are located directly behind the pump 222. The heat exchanger 223 heats or cools the heat medium supplied to the piping 229 to a set temperature. The flow sensor 224 detects the flow rate of the heat medium supplied by the pump 222 at the outlet side of the piping 229. The pressure sensor 225 detects the pressure of the heat medium supplied by the pump 222 at the outlet side of the piping 229. Temperature sensor 226 detects the temperature of the heat medium supplied by pump 222 at the outlet side of pipe 229. Variable valve 227, together with variable valve 228 on the side of pipe 230 which serves as a return pipe, adjusts the pressure of the heat medium supplied by pump 222 in pipe 229.

[0037] The second temperature control unit 240 is connected to pipe 16a via pipe 249, pipe 213, and valve 201. Furthermore, the second temperature control unit 240 is connected to pipe 16b via pipe 250, pipe 215, and check valve 205. Moreover, the connection point D between pipe 249 and pipe 213 and the connection point E between pipe 250 and pipe 215 are connected via pipe 214, which serves as a bypass pipe. Furthermore, a pressure sensor 209 for monitoring is provided at connection point E.

[0038] In this embodiment, the second temperature control unit 240 controls the temperature of the second heat medium. The second temperature control unit 240 mixes the temperature-controlled second heat medium with the heat medium circulating from pipe 207 to pipe 16a via pipe 249, pipe 213, and valve 201, and supplies this mixture into the flow path 15 of the lower electrode LE. Furthermore, the temperature of the second heat medium is lower than the temperature of the first heat medium, for example, it can be set to -10°C. Furthermore, the temperature of the second heat medium can be any temperature as long as it is lower than the temperature of the first heat medium. The pressure in pipes 213-215, 249, and 250 decreases due to the supply of the second heat medium into the flow path 15 of the lower electrode LE. Then, a portion of the heat medium discharged from flow path 15 flows back to the second temperature control unit 240 at connection point A of pipe 16b, through check valve 205 which opens due to pressure reduction, via pipes 215 and 250. The piping including pipes 249, 213, and 16a is an example of a supply piping or a second supply piping. Furthermore, the piping including pipes 16b, 215, and 250 is an example of a return piping or a second return piping. Moreover, the piping including pipes 213-215, 249, and 250 is an example of a second piping.

[0039] In the second temperature control unit 240, a pump 242 supplies heat medium from the storage tank 241 to the piping 249. Furthermore, a heat exchanger 243, a flow sensor 244, a pressure sensor 245, a temperature sensor 246, and a variable valve 247 are provided on the outlet side of the pump 242. That is, the heat exchanger 243, flow sensor 244, pressure sensor 245, temperature sensor 246, and variable valve 247 are located directly behind the pump 242. The heat exchanger 243 heats or cools the heat medium supplied to the piping 249 to a set temperature. The flow sensor 244 detects the flow rate of the heat medium supplied by the pump 242 at the outlet side of the piping 249. The pressure sensor 245 detects the pressure of the heat medium supplied by the pump 242 at the outlet side of the piping 249. Temperature sensor 246 detects the temperature of the heat medium supplied by pump 242 at the outlet side of pipe 249. Variable valve 247, together with variable valve 248 on the side of pipe 250 which serves as a return pipe, adjusts the pressure of the heat medium supplied by pump 242 in pipe 249.

[0040] The storage tank 221 of the first temperature control unit 220 and the storage tank 241 of the second temperature control unit 240 are connected by pipes 251 and 252. Pipes 251 and 252 are examples of connecting pipes used to adjust the liquid level of the storage tank 221 storing the first heat medium and the storage tank 241 storing the second heat medium. Pipe 251 is used to allow the gas (air or evaporating heat medium, etc.) between the storage tanks 221 and 241 to move between each other. Pipe 252 is used to allow the liquid (heat medium) between the storage tanks 221 and 241 to move between each other. This prevents leakage of the heat medium.

[0041] The opening degrees of valves 201, 227, 228, 247, and 248, the delivery pressures of pumps 202, 222, and 242, and the temperatures of heat exchangers 223 and 243 are controlled separately by control device 11. Furthermore, pumps 202, 222, and 242 are pumps whose delivery pressures can be controlled according to the frequency of the converter. Moreover, the opening degree of valve 201 can be adjusted, for example, between +100% and -100%. When valve 201 is opened at 0%, all heat medium from pipe 207 flows into pipe 16a, while heat medium from pipes 210 and 213 does not flow into pipe 16a. Similarly, when valve 201 is opened at +100%, all heat medium from pipe 210 flows into pipe 16a, while heat medium from pipes 207 and 213 does not flow into pipe 16a. On the other hand, when valve 201 is at -100% opening, all the heat medium from pipe 213 flows into pipe 16a, while the heat medium from pipes 207 and 210 does not flow into pipe 16a.

[0042] That is, when it is necessary to mix the first heat medium on the high-temperature side to increase the temperature of the circulating heat medium, the opening of valve 201 is changed from 0% to the positive side. On the other hand, when it is necessary to mix the second heat medium on the low-temperature side to decrease the temperature of the circulating heat medium, the opening of valve 201 is changed from 0% to the negative side. For example, when plasma is ignited in the processing space PS to perform plasma treatment, heat is also input from the plasma to the lower electrode LE. Therefore, in order to keep the temperature of the lower electrode LE fixed, for example, the opening of valve 201 is set to -10%, the flow rate of the heat medium circulating in pipe 207 is set to 90%, and 10% of the second heat medium on the low-temperature side of pipe 213 is mixed.

[0043] [Structure of the connecting pipe] Next, the structure of the connecting pipe in this embodiment will be explained. Figure 3 is a diagram showing an example of the structure of the connecting pipe between the connecting slots in this embodiment.

[0044] As shown in Figure 3, the high-temperature storage tank 221 and the low-temperature storage tank 241 are connected by a pipe 251 serving as a gas connecting pipe and a pipe 252 serving as a liquid (heat medium) connecting pipe. The pipe 251 connects the top surface of the storage tank 221 and the top surface of the storage tank 241. Furthermore, the storage tank 221 is an example of the first tank, and the storage tank 241 is an example of the second tank.

[0045] During heat medium circulation, the liquid level in storage tanks 221 and 241 is maintained approximately between the upper and lower limits of the appropriate liquid volume management range. The appropriate management range defines the amount of heat medium for which temperature control of the object being controlled can be stably performed. Furthermore, in the following description, the upper limit liquid level is represented as "High" and the lower limit liquid level as "Low" in Figures 3 to 8. To prevent heat medium from overflowing from the pressure relief valve (not shown) located on the top surface of storage tanks 221 and 241, the upper limit liquid level is set as the liquid level that allows the heat medium to move to another storage tank. To prevent the pumps 222 and 242 supplying the heat medium from running dry, the lower limit liquid level is set as the liquid level that ensures a certain liquid volume in storage tanks 221 and 241.

[0046] Pipe 252 connects the lower limit liquid level of storage tank 221 to the upper limit liquid level of storage tank 241. During heat medium circulation, the liquid level in pipe 252 is set to be the same as the liquid level in storage tank 221. Furthermore, the heat medium does not move between storage tank 221 and storage tank 241 via pipe 252. That is, since the heat medium in the high-temperature storage tank 221 and the heat medium in the low-temperature storage tank 241 do not mix, energy loss caused by maintaining their respective temperatures can be reduced in heat media with large temperature differences. Moreover, pipe 252 can also connect the upper limit liquid level of storage tank 221 to the lower limit liquid level of storage tank 241.

[0047] Figure 4 is a diagram showing an example of the change in liquid level during heating in this embodiment. As shown in Figure 4, when the temperature of the lower electrode LE is increased, the heat medium on the high-temperature side is supplied via pipe 229, so the liquid level in the storage tank 221 drops. On the other hand, the liquid level in the storage tank 241 rises because the heat medium on the low-temperature side stops being supplied. The heat medium in the storage tank 241 moves to the storage tank 221 via pipe 252 only by an amount exceeding the upper limit liquid level. Therefore, the liquid level in the storage tank 221 is maintained at the lower limit liquid level, and the liquid level in the storage tank 241 does not significantly exceed the upper limit liquid level. At this time, the amount of heat medium moving from the low-temperature storage tank 241 to the high-temperature storage tank 221 is limited, so the temperature drop of the heat medium in the high-temperature storage tank 221 can be reduced, and the energy loss caused by maintaining a constant temperature can be reduced.

[0048] Figure 5 is a diagram illustrating an example of the liquid level change during cooling in this embodiment. As shown in Figure 5, when the temperature of the lower electrode LE is lowered, the heat medium on the low-temperature side is supplied via pipe 249, thus the liquid level in the storage tank 241 drops. On the other hand, the liquid level in the storage tank 221 rises because the heat medium on the high-temperature side stops being supplied. The heat medium in the storage tank 221 moves to the storage tank 241 via pipe 252 only by an amount exceeding the upper limit liquid level. Therefore, the liquid level in the storage tank 241 remains at the lower limit liquid level, and the liquid level in the storage tank 221 does not significantly exceed the upper limit liquid level. At this time, the amount of heat medium moving from the high-temperature side storage tank 221 to the low-temperature side storage tank 241 is limited, thus reducing the temperature rise of the heat medium in the low-temperature side storage tank 241 and reducing the energy loss caused by maintaining a constant temperature.

[0049] [Variation 1] In the above embodiment, the storage tank 221 on the high-temperature side and the storage tank 241 on the low-temperature side are directly connected by piping 252. However, they can also be connected via a tank at room temperature (the same temperature as the surrounding environment). In this case, the embodiment will be described as Variation 1. Furthermore, part of the substrate processing apparatus and temperature control device in Variation 1 are the same as those in the above embodiment, so repeated descriptions of the configuration and operation are omitted.

[0050] Figure 6 is a diagram showing an example of the configuration of the connecting pipe between the connecting tanks in Variation 1. As shown in Figure 6, in Variation 1, an intermediate tank 280 is provided between storage tank 221 and storage tank 241. The storage tank 221 on the high-temperature side and the intermediate tank 280 are connected by a pipe 251a, which serves as a gas connecting pipe, and a pipe 252a, which serves as a liquid (heat medium) connecting pipe. Pipe 251a connects the top surface of storage tank 221 and the top surface of intermediate tank 280. Furthermore, the storage tank 241 on the low-temperature side and the intermediate tank 280 are connected by a pipe 251b, which serves as a gas connecting pipe, and a pipe 252b, which serves as a liquid (heat medium) connecting pipe. Pipe 251b connects the top surface of storage tank 241 and the top surface of intermediate tank 280.

[0051] The intermediate tank 280 is not temperature-controlled. The heat medium in the intermediate tank 280 exchanges heat with the outside atmosphere through the wall of the intermediate tank 280. It is at room temperature (e.g., 20°C) as long as no heat medium flows into the storage tank 221 or storage tank 241. That is, a third heat medium at room temperature is stored in the intermediate tank 280. The intermediate tank 280 is an example of a third tank. The bottom surface of the intermediate tank 280 is at a higher position than the storage tanks 221 and 241. In this way, the liquid level of the intermediate tank 280 is controlled with a minimum liquid volume. Furthermore, the top surface of the intermediate tank 280 is at the same position as the storage tanks 221 and 241. The liquid level in the storage tanks 221, 241 and the intermediate tank 280 is maintained approximately between the upper and lower liquid levels during heat medium circulation, similar to the above embodiment.

[0052] Pipe 252a connects the upper limit liquid level of storage tank 221 to the lower limit liquid level of intermediate tank 280. During heat medium circulation, the liquid level in pipe 252a is the same as the liquid level in intermediate tank 280. Furthermore, the heat medium does not move between storage tank 221 and intermediate tank 280 via pipe 252a. That is, the heat medium in high-temperature storage tank 221 and the heat medium in room-temperature intermediate tank 280 do not mix, thus reducing energy loss caused by maintaining the temperature on the high-temperature side in heat media with large temperature differences. Moreover, pipe 252a can also connect the lower limit liquid level of storage tank 221 to the upper limit liquid level of intermediate tank 280.

[0053] Pipe 252b connects the upper limit liquid level of storage tank 241 to the lower limit liquid level of intermediate tank 280. During heat medium circulation, the liquid level in pipe 252b is the same as the liquid level in intermediate tank 280. Furthermore, the heat medium does not move between storage tank 241 and intermediate tank 280 via pipe 252b. That is, the heat medium in storage tank 241 at low temperature and the heat medium in intermediate tank 280 at normal temperature do not mix, thus reducing energy loss caused by maintaining the temperature on the low temperature side in heat media with large temperature differences. Moreover, pipe 252b can also connect the lower limit liquid level of storage tank 241 to the upper limit liquid level of intermediate tank 280.

[0054] During heat medium circulation in storage tanks 221, 241 and intermediate tank 280, spaces 282 to 284 exist above the liquid surface. Spaces 282 to 284 can be used, for example, as tanks for storing heat medium during maintenance of the substrate processing apparatus 1. By providing intermediate tank 280, even if the capacity of storage tanks 221 and 241 is reduced, the same amount of heat medium as in the above embodiment can be stored in storage tanks 221, 241 and intermediate tank 280.

[0055] Figure 7 is a diagram illustrating an example of the liquid level change during heating in Variation 1. As shown in Figure 7, when the temperature of the lower electrode LE is increased, the heat transfer medium on the high-temperature side is supplied via pipe 229, thus lowering the liquid level in storage tank 221. On the other hand, the liquid level in storage tank 241 rises because the heat transfer medium on the low-temperature side stops being supplied. The heat transfer medium in storage tank 241 moves to intermediate tank 280 via pipe 252b only by an amount exceeding the upper limit liquid level. When the liquid level in intermediate tank 280 rises, the heat transfer medium moves to storage tank 221 via pipe 252a only by an amount exceeding the upper limit liquid level. Therefore, the liquid level in storage tank 221 remains at the lower limit liquid level, and the liquid levels in storage tank 241 and intermediate tank 280 do not significantly exceed the upper limit liquid level. At this time, the movement of the heat medium from the low-temperature storage tank 241 to the high-temperature storage tank 221 is restricted, and it temporarily passes through the intermediate tank 280 at room temperature. Therefore, the temperature drop of the heat medium in the high-temperature storage tank 221 can be further reduced, and the energy loss caused by maintaining a constant temperature can be further reduced. That is, the room-temperature heat medium flowing into the intermediate tank 280 from the high-temperature storage tank 221 reduces the energy loss caused by maintaining a constant temperature compared to the case where the low-temperature heat medium flows into the low-temperature storage tank 241.

[0056] Figure 8 is a diagram illustrating an example of the liquid level change during cooling in Variation 1. As shown in Figure 8, when the temperature of the lower electrode LE is lowered, the heat transfer medium on the low-temperature side is supplied via pipe 249, thus causing the liquid level in storage tank 241 to drop. On the other hand, the liquid level in storage tank 221 rises because the heat transfer medium on the high-temperature side stops being supplied. The heat transfer medium in storage tank 221 moves to intermediate tank 280 via pipe 252a only by an amount exceeding the upper limit liquid level. When the liquid level in intermediate tank 280 rises, the heat transfer medium moves to storage tank 241 via pipe 252b only by an amount exceeding the upper limit liquid level. Therefore, the liquid level in storage tank 241 remains at the lower limit liquid level, and the liquid levels in storage tank 221 and intermediate tank 280 do not significantly exceed the upper limit liquid level. At this time, the movement of the heat medium from the high-temperature storage tank 221 to the low-temperature storage tank 241 is restricted, and it temporarily passes through the intermediate tank 280 at room temperature. Therefore, the temperature rise of the heat medium in the low-temperature storage tank 241 can be reduced, and the energy loss caused by maintaining a constant temperature can be reduced. That is, the room-temperature heat medium flowing into the intermediate tank 280 from the low-temperature storage tank 241 reduces the energy loss caused by maintaining a constant temperature compared to the case where the high-temperature heat medium flows into the high-temperature storage tank 221.

[0057] [Variation 2] In the above embodiment, the lower limit liquid level of the storage tank 221 and the upper limit liquid level of the storage tank 241 are connected by piping 252. However, the storage tank 221 on the high-temperature side can also be positioned offset along the height direction and connected by horizontal piping. In this case, the embodiment will be described as Variation 2. Furthermore, part of the configuration of the substrate processing apparatus and the temperature control device in Variation 2 is the same as in the above embodiment, so repeated descriptions of the configuration and operation are omitted.

[0058] Figure 9 is a diagram showing an example of the configuration of the connecting pipe between the connecting tanks in Variation 2. As shown in Figure 9, in Variation 2, the arrangement of the storage tank 221 is offset upward in the height direction, becoming storage tank 221a. That is, the top and bottom surfaces of storage tank 221a are higher than storage tank 241, respectively. Storage tank 221a and storage tank 241 are connected by a pipe 251, which serves as a gas connecting pipe, and a pipe 252c, which serves as a liquid (heat medium) connecting pipe. Pipe 251 connects the top surface of storage tank 221a and the top surface of storage tank 241.

[0059] When the heat transfer medium on the storage tank 221a side circulates in the lower electrode LE, the liquid level in the storage tank 221a is maintained at approximately the middle of a suitable management range. Pipeline 252c is horizontally connected to the storage tank 241 at the upper liquid level of the storage tank 221a. As shown in Figure 9, when the heat transfer medium on the storage tank 221a side circulates in the lower electrode LE, the heat transfer medium does not move between the storage tank 221a and the storage tank 241 via pipe 252c. That is, the heat transfer medium in the high-temperature storage tank 221a and the heat transfer medium in the low-temperature storage tank 241 do not mix, thus reducing energy loss caused by maintaining the respective temperatures of the heat transfer media with large temperature differences.

[0060] Figure 10 is a diagram illustrating an example of the liquid level change during cooling in Variation Example 2. As shown in Figure 10, when the temperature of the lower electrode LE is lowered, the heat medium on the low-temperature side is supplied via pipe 249, thus lowering the liquid level in storage tank 241. On the other hand, the liquid level in storage tank 221a rises because the heat medium on the high-temperature side stops being supplied. The heat medium in storage tank 221a moves to storage tank 241 via pipe 252c only by an amount exceeding the upper limit liquid level. Therefore, the liquid level in storage tank 241 remains at the lower limit liquid level, and the liquid level in storage tank 221a does not significantly exceed the upper limit liquid level. At this time, the amount of heat medium moving from storage tank 221a on the high-temperature side to storage tank 241 on the low-temperature side is limited, thus reducing the temperature rise of the heat medium in storage tank 241 on the low-temperature side and reducing energy loss caused by maintaining a constant temperature.

[0061] Subsequently, when the temperature of the lower electrode LE is raised, the heat medium on the high-temperature side is supplied through pipe 229, causing the liquid level in storage tank 221a to drop. On the other hand, the liquid level in storage tank 241 rises as the supply of heat medium on the low-temperature side stops. That is, when the heat medium on the storage tank 221a side returns to the state of circulating in the lower electrode LE, the height of the liquid level in storage tank 221a and storage tank 241 also substantially returns to the state shown in Figure 9.

[0062] [Variation 3] In the above embodiment, a temperature control device 20 of the type in which the heat medium circulates within the circulation section 200 was described. However, a temperature control device of the type that switches the heat medium flowing in the flow path 15 within the lower electrode LE to a first heat medium and a second heat medium may also be used. In this case, the embodiment is described as Variation 3. Furthermore, part of the configuration of the substrate processing apparatus and the temperature control device, as well as the pressure control method, are the same as in the above embodiment. Therefore, repeated descriptions of the configuration and operation are omitted.

[0063] Figure 11 is a diagram showing one example of the temperature control device of Variation 3. Compared with the temperature control device 20 of the above embodiment, the temperature control device 20a shown in Figure 11 has a switching unit 260, a first temperature control unit 220a, and a second temperature control unit 240a instead of the circulation unit 200, the first temperature control unit 220, and the second temperature control unit 240a. Furthermore, the switching unit 260 has valves 261 to 264, a temperature sensor 265, and piping 266 to 271.

[0064] The first temperature control unit 220a is connected to pipe 16a via pipe 272, pipe 266, and valve 261. Furthermore, the first temperature control unit 220a is connected to pipe 16b via pipe 273, pipe 268, and valve 262. In variation 3, the first temperature control unit 220a controls the temperature of the first heat medium located on the high-temperature side. The first temperature control unit 220a supplies the temperature-controlled first heat medium to the flow path 15 of the lower electrode LE via pipe 272, pipe 266, valve 261, and pipe 16a. Then, the heat medium supplied to the flow path 15 of the lower electrode LE flows back to the first temperature control unit 220a via pipe 16b, valve 262, pipe 268, and pipe 273. The piping including pipes 272, 266 and 16a is an example of a supply piping or a first supply piping. Also, the piping including pipes 16b, 268 and 273 is an example of a return piping or a first return piping.

[0065] The second temperature control unit 240a is connected to pipe 16a via pipe 274, pipe 269, and valve 261. Furthermore, the second temperature control unit 240a is connected to pipe 16b via pipe 275, pipe 271, and valve 262. In variation 3, the second temperature control unit 240a controls the temperature of the second heat medium on the low-temperature side. The second temperature control unit 240a supplies the temperature-controlled second heat medium to the flow path 15 of the lower electrode LE via pipe 274, pipe 269, valve 261, and pipe 16a. Then, the heat medium supplied to the flow path 15 of the lower electrode LE flows back to the second temperature control unit 240a via pipe 16b, valve 262, pipe 271, and pipe 275. The piping including pipes 274, 269 and 16a is an example of a supply piping or a second supply piping. Also, the piping including pipes 16b, 271 and 275 is an example of a return piping or a second return piping.

[0066] Valve 261 is provided at the connection between pipe 16a and pipes 266 and 269, and switches the heat medium flowing in the flow path 15 of the lower electrode LE to either the first heat medium or the second heat medium. Valve 262 is provided at the connection between pipe 16b and pipes 268 and 271, and switches the output destination of the heat medium flowing out of the flow path 15 of the lower electrode LE to either the first temperature control unit 220a or the second temperature control unit 240a.

[0067] The connection point F between pipe 272 and pipe 266 and the connection point G between pipe 273 and pipe 268 are connected by pipe 267, which serves as a bypass pipe. A bypass valve 263 is provided in pipe 267.

[0068] The connection position H between pipe 274 and pipe 269 and the connection position I between pipe 275 and pipe 271 are connected by pipe 270, which serves as a bypass pipe. A bypass valve 264 is provided in pipe 270.

[0069] A temperature sensor 265 for measuring the temperature at the inlet side of the flow path 15 is provided in the piping 16a within the temperature control device 20a. Alternatively, the temperature sensor 265 may be located outside the temperature control device 20a. For example, the temperature sensor 265 may be located directly below the lower electrode LE, for example, at the connection between the piping 16a and the flow path 15, or it may be located between the lower electrode LE and the temperature control device 20a.

[0070] The opening and closing of valves 261, 262 and bypass valves 263, 264 are controlled by the control device 11 respectively. Furthermore, the first temperature control unit 220a and the second temperature control unit 240a are the same as the first temperature control unit 220 and the second temperature control unit 240 in the above embodiment, except that they do not have variable valves 227, 228 and variable valves 247, 248, so their description is omitted.

[0071] In the temperature control device 20a, when the first heat medium on the high-temperature side is supplied to the flow path 15 of the lower electrode LE, valve 261 opens the pipe 266 side and closes the pipe 269 side, valve 262 opens the pipe 268 side and closes the pipe 271 side. Furthermore, bypass valve 263 is closed and bypass valve 264 is open. Therefore, after the first heat medium on the high-temperature side supplied by the first temperature control unit 220a is supplied to the flow path 15 of the lower electrode LE, it flows back to the first temperature control unit 220a, and the second heat medium on the low-temperature side supplied by the second temperature control unit 240a flows back to the second temperature control unit 240a via bypass valve 264.

[0072] On the other hand, in the temperature control device 20a, when the second heat medium on the low-temperature side is supplied to the flow path 15 of the lower electrode LE, valve 261 closes the pipe 266 side and opens the pipe 269 side, valve 262 closes the pipe 268 side and opens the pipe 271 side. Also, bypass valve 263 opens and bypass valve 264 closes. Therefore, after the second heat medium on the low-temperature side supplied by the second temperature control unit 240a is supplied to the flow path 15 of the lower electrode LE, it flows back to the second temperature control unit 240a, and the first heat medium on the high-temperature side supplied by the first temperature control unit 220a flows back to the first temperature control unit 220a via bypass valve 263.

[0073] As shown in Figure 11, similar to the temperature control device 20, the high-temperature storage tank 221 and the low-temperature storage tank 241 are connected by a pipe 251 serving as a gas connecting pipe and a pipe 252 serving as a liquid (heat medium) connecting pipe. The pipe 251 connects the top surface of the storage tank 221 and the top surface of the storage tank 241. The pipe 252 connects the lower limit liquid level of the storage tank 221 and the upper limit liquid level of the storage tank 241. Therefore, similar to the temperature control device 20, the heat medium in the high-temperature storage tank 221 and the heat medium in the low-temperature storage tank 241 will not mix, thus reducing energy loss caused by maintaining the temperature of each heat medium with a large temperature difference. Furthermore, in variation 3, the intermediate tank 280 can also be provided in the same manner as in variation 1.

[0074] As described above, according to this embodiment, the temperature control devices 20 and 20a include: a first tank (storage tank 221) for storing a first heat medium; a second tank (storage tank 241) for storing a second heat medium with a temperature different from that of the first heat medium; and a first connecting pipe (pipeline 252) connecting the upper limit of the liquid level in the first tank to the lower limit of the liquid level in the second tank. As a result, energy loss caused by maintaining the temperature of a heat medium with a large temperature difference can be reduced.

[0075] Furthermore, according to this embodiment, the first tank and the second tank each have a liquid portion and a gas portion inside, and a second connecting pipe (pipe 251) is formed in such a way that the gas portion inside the first tank and the gas portion inside the second tank are interconnected. As a result, the heat medium can move smoothly between the tanks.

[0076] Furthermore, according to this embodiment, the second connecting pipe is positioned in the first and second tanks at a level higher than their respective upper limits. As a result, gas can move between the tanks.

[0077] Furthermore, according to this embodiment, the second connecting pipe is disposed between the top surface of the first groove and the top surface of the second groove. As a result, gas can move between the grooves.

[0078] Furthermore, according to Variation 1, the temperature control device 20 includes: a first tank (storage tank 221) storing a first heat medium; a second tank (storage tank 241) storing a second heat medium with a temperature different from that of the first heat medium; a third tank (intermediate tank 280) storing a third heat medium; a first connecting pipe (pipe 252a) connecting the first tank and the third tank; and a second connecting pipe (pipe 252b) connecting the second tank and the third tank. The first connecting pipe is a connecting pipe that connects the upper limit of the liquid level in the first tank to the lower limit of the liquid level in the third tank, or a connecting pipe that connects the lower limit of the liquid level in the first tank to the upper limit of the liquid level in the third tank. Furthermore, the second connecting pipe system connects the upper limit liquid level in the second tank to the lower limit liquid level in the third tank, or connects the lower limit liquid level in the second tank to the upper limit liquid level in the third tank. As a result, energy loss caused by maintaining the temperature of the heat transfer medium with a large temperature difference can be reduced.

[0079] Furthermore, according to Variation Example 1, the bottom surface of the third tank is positioned higher than that of the first and second tanks. As a result, liquid level control via the third tank (intermediate tank 280) can be achieved with a minimum liquid volume.

[0080] Furthermore, according to Variation Example 1, the third heat medium is at room temperature. As a result, energy loss caused by maintaining the temperature of a heat medium with a large temperature difference can be reduced.

[0081] Furthermore, according to Variation 1, the third tank is not temperature controlled. As a result, the temperature of the heat medium stored in the third tank (intermediate tank 280) can be maintained without consuming energy.

[0082] Furthermore, according to Variation 1, the first, second, and third tanks each have a liquid portion and a gas portion inside, and each has a third connecting pipe (251a) formed to connect the gas portion inside the first tank with the gas portion inside the third tank, and a fourth connecting pipe (251b) formed to connect the gas portion inside the second tank with the gas portion inside the third tank. As a result, the heat medium can move smoothly between the tanks.

[0083] Furthermore, according to Variation 1, the third connecting pipe is positioned higher than the upper limit liquid level of both the first and third tanks, and the fourth connecting pipe is positioned higher than the upper limit liquid level of both the second and third tanks. As a result, gas can move between the tanks.

[0084] Furthermore, according to Variation 1, the third connecting pipe is disposed between the top surface of the first slot and the top surface of the third slot, and the fourth connecting pipe is disposed between the top surface of the second slot and the top surface of the third slot. This allows gas to move between the slots.

[0085] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The above embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended patent applications.

[0086] Furthermore, in the above embodiment, capacitively coupled plasma (CCP) is used as one example of a plasma source, but the disclosed technology is not limited to this. As a plasma source, inductively coupled plasma (ICP), microwave-excited surface wave plasma (SWP), electron cyclotron resonance plasma (ECP), or large horn wave excited plasma (HWP) can also be used, for example.

[0087] Furthermore, in the above embodiment, a plasma etching apparatus was described as an example of a substrate processing apparatus 1, but the disclosed technology is not limited thereto. As long as the apparatus uses a temperature-controlled heat medium to control the temperature of the temperature-controlled object such as the wafer W, the disclosed technology can also be applied to film forming apparatuses, modification apparatuses, or cleaning apparatuses, in addition to etching apparatuses. [Simplified Explanation of the Diagram]

[0008] FIG1 is a schematic cross-sectional view showing an example of a substrate processing apparatus according to one embodiment of the present invention. FIG2 is a diagram showing an example of a temperature control device according to this embodiment. FIG3 is a diagram showing an example of the configuration of the connecting pipe between the connecting tanks according to this embodiment. FIG4 is a diagram showing an example of the change in liquid level during heating according to this embodiment. FIG5 is a diagram showing an example of the change in liquid level during cooling according to this embodiment. FIG6 is a diagram showing an example of the configuration of the connecting pipe between the connecting tanks in Variation 1. FIG7 is a diagram showing an example of the change in liquid level during heating according to Variation 1. FIG8 is a diagram showing an example of the change in liquid level during cooling according to Variation 1. FIG9 is a diagram showing an example of the configuration of the connecting pipe between the connecting tanks in Variation 2. FIG10 is a diagram showing an example of the change in liquid level during cooling according to Variation 2. FIG11 is a diagram showing an example of a temperature control device in Variation 3.

Claims

1. A temperature control device comprising: a first tank storing a first heat medium; a second tank storing a second heat medium at a temperature different from that of the first heat medium; and a first connecting pipe configured to connect a first position of the first tank to a second position in the second tank that is lower than the first position, and configured to allow the first heat medium to flow to the second tank and the second heat medium to flow to the first tank based on the level difference between the first heat medium and the second heat medium; wherein the first tank and the second tank each have a liquid portion and a gas portion; and the temperature control device further comprises a second connecting pipe formed in such a way as to allow the gas portion in the first tank to communicate with the gas portion in the second tank.

2. The temperature control device of claim 1, wherein the second connecting pipe is positioned at a level higher than the upper limit of the liquid level of each of the first and second tanks.

3. The temperature control device as claimed in claim 2, wherein the second connecting pipe is disposed between the top surface of the first groove and the top surface of the second groove.

4. A substrate processing apparatus comprising: a processing container; a mounting stage disposed within the processing container and holding a substrate thereon; a first temperature control unit that supplies the first heat medium from a first tank storing the first heat medium to a flow path disposed inside the mounting stage via a first pipe; a second temperature control unit that supplies the second heat medium from a second tank storing the second heat medium at a temperature different from that of the first heat medium to the flow path via a second pipe; and a first connecting pipe configured to connect a first position of the first tank to a second position of the second tank that is lower than the first position, and configured to allow the first heat medium to flow to the second tank and the second heat medium to flow to the first tank based on the positional difference between the first heat medium and the second heat medium.

5. The substrate processing apparatus of claim 4, wherein the first tank and the second tank respectively have a liquid portion and a gas portion; and the substrate processing apparatus further comprises a second connecting pipe formed in such a way as to communicate the gas portion inside the first tank with the gas portion inside the second tank.

6. The substrate processing apparatus of claim 5, wherein the second connecting pipe is disposed at a position higher than the upper limit of the liquid level of the first tank and the second tank respectively.

7. The substrate processing apparatus of claim 6, wherein the second connecting pipe is disposed between the top surface side of the first groove and the top surface side of the second groove.

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