Heat medium circulation system and substrate processing apparatus

Abstract

Provided is a heat medium circulating system and a substrate processing apparatus. The exhaust efficiency of a permeation gas that permeates a resin-made pipe is improved. The heat medium circulating system has: a pipe that is resin-made and constitutes at least a part of a circulating flow path in which a heat medium circulates around a temperature control target; a cover that surrounds the outer peripheral surface of the pipe; and an exhaust pipe that is connected to the space between the pipe and the cover and exhausts the heat medium that permeates the pipe and is released into the space, the cover having an air supply port that supplies air to the space between the pipe and the cover simultaneously with the exhaust of the heat medium from the exhaust pipe.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a heat medium circulation system and a substrate processing apparatus. BACKGROUND

[0002] In a substrate processing apparatus or the like for processing a substrate such as a semiconductor wafer (hereinafter, referred to as "wafer"), in a case where a temperature of a member in the apparatus is to be controlled, a circulation flow path in which a heat medium is circulated to the member as a temperature control target is formed. In the circulation flow path in which the heat medium is circulated, there is a case where a pipe made of a resin having high flexibility is used.

[0003] In a case where the pipe made of the resin is used in a part of the circulation flow path in which a high-temperature heat medium is circulated, there is a case where a component of the heat medium flowing in the pipe made of the resin permeates the pipe made of the resin and is released to the surroundings of the pipe as a permeated gas. The release of the permeated gas to the surroundings of the pipe becomes a main cause of environmental pollution, and it is not desirable that such a case occurs.

[0004] Further, a technology is proposed in which an outer peripheral surface of an inner pipe made of a resin is airtightly surrounded by an outer pipe, an exhaust pipe is connected to a space that is airtight between the inner pipe and the outer pipe, and a permeated gas released from the pipe is exhausted from the exhaust pipe (for example, refer to Patent Literature 1).

[0005] Prior art documents

[0006] Patent documents

[0007] Patent Literature 1: Japanese Patent Application Laid-Open No. 2001-297967 SUMMARY

[0008] Problems to be solved by the invention

[0009] The present disclosure provides a technology capable of improving exhaust efficiency of a permeated gas permeating a pipe made of a resin.

[0010] Solution to the problem

[0011] The heat medium circulation system of the technical solution of the present disclosure has: a pipe made of a resin, which constitutes at least a part of a circulation flow path in which a heat medium is circulated to a temperature control target; a cover that surrounds an outer peripheral surface of the pipe; and an exhaust pipe that is connected to a space between the pipe and the cover and exhausts the heat medium that permeates the pipe and is released to the space, the cover having an air supply port that supplies air to the space between the pipe and the cover in parallel with the exhaust of the heat medium from the exhaust pipe.

[0012] Effects of the invention

[0013] With the present disclosure, the exhaust efficiency of the permeation gas through the resin-made pipe can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a cross-sectional view showing an example of the schematic structure of a plasma processing apparatus of an embodiment.

[0015] Figure 2 is a view schematically showing a conventional circulation flow path of a heat medium circulating a showerhead as a temperature control target member.

[0016] Figure 3 is a view schematically showing the structure of a pipe of an embodiment.

[0017] Figure 4 is a view schematically showing the structure of a pipe of an embodiment.

[0018] Figure 5 is a view showing a modification example of a cover. DETAILED DESCRIPTION

[0019] Hereinafter, various embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions will be denoted by the same reference numerals.

[0020] To prevent the permeation gas from diffusing to the surroundings, it can be considered to close the surroundings of the pipe with an outer pipe (cover) as in Patent Literature 1, and to exhaust the closed space between the pipe and the cover with a pump. However, if the distance between the closed space and the pump is long, the conductivity deteriorates, and thus the permeation gas in the closed space cannot be sufficiently exhausted. In addition, in the case where the pipe is disposed in an atmospheric atmosphere, there is a concern that the pipe and the cover approach each other, the closed space shrinks, and the exhaust efficiency of the permeation gas decreases due to the pressure difference between the closed space which is depressurized and the atmosphere. Here, it is desirable to improve the exhaust efficiency of the permeation gas through the resin-made pipe.

[0021] [Structure of substrate processing apparatus]

[0022] First, the structure of the substrate processing apparatus of an embodiment will be described. The substrate processing apparatus is an apparatus that performs predetermined substrate processing on a substrate such as a wafer. The present embodiment will be described taking the case where the substrate processing apparatus is a plasma processing apparatus 10 that performs processing such as plasma etching on a wafer W as a substrate. Figure 1 is a cross-sectional view showing an example of the schematic structure of a plasma processing apparatus 10 of an embodiment. Figure 1The plasma processing apparatus 10 shown is a plasma etching apparatus using a capacitively coupled plasma (CCP). The plasma processing apparatus 10 includes a substantially cylindrical processing vessel 12. The processing vessel 12 is composed of, for example, aluminum. In addition, the surface of the processing vessel 12 is subjected to an anodizing treatment.

[0023] A stage 16 is provided inside the processing vessel 12. The stage 16 has an electrostatic chuck 18 and a base 20. The upper surface of the electrostatic chuck 18 is a placement surface on which a processed object to be subjected to plasma processing is placed. In the case of the present embodiment, a wafer W is placed on the upper surface of the electrostatic chuck 18 as the processed object. The base 20 has a substantially disc shape and is composed mainly of a conductive metal such as aluminum. The base 20 constitutes a lower electrode. The base 20 is supported by a support portion 14. The support portion 14 is a cylindrical member extending from the bottom of the processing vessel 12.

[0024] The electrostatic chuck 18 is provided on the base 20. The electrostatic chuck 18 attracts and holds the wafer W by electrostatic force such as Coulomb force. An electrode E1 for electrostatic attraction is provided in the main body portion of the electrostatic chuck 18. A direct-current power supply 22 is electrically connected to the electrode E1 by means of a switch SW1. The attraction force for holding the wafer W depends on the value of the direct-current voltage applied from the direct-current power supply 22. In addition, a heat transfer gas such as He gas can be supplied between the upper surface of the electrostatic chuck 18 and the back surface of the wafer W by means of a heat transfer gas supply mechanism and a gas supply line, neither of which is shown.

[0025] A focus ring FR is arranged around the wafer W on the electrostatic chuck 18 of the stage 16. The focus ring FR is provided in order to improve the uniformity of plasma processing. The focus ring FR is composed of a material selected as appropriate in accordance with the plasma processing to be performed. For example, the focus ring FR is composed of silicon or quartz.

[0026] A refrigerant flow path 24 is formed inside the base 20. Refrigerant is supplied to the refrigerant flow path 24 from a cooling unit provided outside the processing vessel 12 via a pipe 26a. The refrigerant supplied to the refrigerant flow path 24 is returned to the cooling unit via a pipe 26b.

[0027] A showerhead 30 is provided inside the processing vessel 12. The showerhead 30 is arranged above the stage 16 so as to oppose the stage 16. The stage 16 and the showerhead 30 are arranged substantially parallel to each other. The showerhead 30 and the stage 16 function as a pair of electrodes (an upper electrode and a lower electrode).

[0028] The showerhead 30 is supported to the upper portion of the processing vessel 12 by means of an insulating shield member 32. The showerhead 30 includes a top plate 34 arranged so as to oppose the stage 16 and a support portion 36 supporting the top plate 34.

[0029] The top plate 34 is configured to face the stage 16 and has a plurality of vents 34a formed for ejecting processing gas into the processing container 12. The top plate 34 is formed of, for example, silicon, SiC, etc.

[0030] The support portion 36 is made of a conductive material, such as aluminum with an anodized surface, and is configured to support the top plate 34 in a manner that allows it to be easily attached and detached from its lower part.

[0031] A gas diffusion chamber 36a is formed inside the support portion 36 for supplying processing gas to a plurality of vents 34a. A plurality of gas flow holes 36b are formed at the bottom of the support portion 36, below the gas diffusion chamber 36a. The plurality of gas flow holes 36b are connected to the plurality of vents 34a.

[0032] A gas inlet 36c is formed in the support portion 36 for introducing processing gas into the gas diffusion chamber 36a. The gas inlet 36c is connected to the gas supply pipe 38.

[0033] A gas source assembly 40 is connected to the gas supply pipe 38 via a valve assembly 42 and a flow controller assembly 44. The valve assembly 42 has multiple on / off valves. The flow controller assembly 44 has multiple flow controllers, such as mass flow controllers. Additionally, the gas source assembly 40 has gas sources for various gases required for plasma processing. The multiple gas sources of the gas source assembly 40 are connected to the gas supply pipe 38 via corresponding on / off valves and corresponding mass flow controllers.

[0034] In the plasma processing apparatus 10, one or more gases from one or more gas sources selected from the plurality of gas sources in the gas source group 40 are supplied to the gas supply pipe 38. The gas supplied to the gas supply pipe 38 reaches the gas diffusion chamber 36a and is dispersed and ejected in a cluster shape into the processing space S through the gas flow hole 36b and the gas hole 34a.

[0035] The nozzle 30 is provided with a temperature control mechanism for temperature adjustment. For example, a flow path 92 is formed inside the support portion 36. The plasma processing apparatus 10 is configured to circulate, for example, a heat medium (salt water) in the flow path 92, thereby enabling control of the temperature of the nozzle 30. The flow path 92 is connected via a pipe to a cooling unit located outside the processing container 12 for the circulation supply of the heat medium. That is, the flow path 92, the pipe, and the cooling unit form a circulation path for the heat medium to circulate in the nozzle 30. A detailed description of the circulation path will follow. The heat medium is, for example, a liquid containing carbon. Examples of liquids containing carbon include ethylene glycol and ethanol.

[0036] The nozzle 30, serving as the upper electrode, is electrically connected to a first high-frequency power supply 61 via a low-pass filter (LPF) (not shown), a matching unit MU1, and a feed rod 60. The first high-frequency power supply 61 is a power source for plasma generation, supplying the nozzle 30 with RF current at frequencies above 13.56 MHz, for example, 60 MHz. The matching unit MU1 is a matching device that matches the load impedance to the internal (or output) impedance of the first high-frequency power supply 61. The matching unit MU1 functions in such a way that the output impedance of the first high-frequency power supply 61 and the load impedance appear to match when plasma is generated within the processing container 12. The output terminal of the matching unit MU1 is connected to the upper end of the feed rod 60.

[0037] The stage 16, serving as the lower electrode, is electrically connected to the second high-frequency power supply 62 via a low-pass filter (LPF) (not shown) and a matching device MU2. The second high-frequency power supply 62 is a power supply for attracting ions (bias), supplying the stage 16 with RF current in the range of 300 kHz to 13.56 MHz, for example, 2 MHz. The matching device MU2 is a matching device that matches the load impedance to the internal (or output) impedance of the second high-frequency power supply 62. The matching device MU2 functions in such a way that the internal impedance of the second high-frequency power supply 62 and the load impedance appear to be identical when plasma is generated within the processing container 12.

[0038] A portion of the nozzle 30 and the feed bar 60 is covered by an upper housing 12a, which is generally cylindrical and extends upward from the side wall of the processing container 12 above the height of the nozzle 30. The upper housing 12a is formed of a conductive material such as aluminum and is grounded via the processing container 11. Various components (e.g., pipes 111 and shrouds 131, described later) are arranged within the space enclosed by the upper housing 12a and the nozzle 30. Figure 4 ).

[0039] In addition, in the plasma processing apparatus 10, a deposit shielding member 46 is provided along the inner wall of the processing container 12 and can be easily attached and detached. Furthermore, a deposit shielding member 46 is also provided on the outer periphery of the support portion 14. The deposit shielding member 46 is a component that prevents etching byproducts (deposits) from adhering to the processing container 12, and is constructed by coating aluminum with ceramics such as Y2O3.

[0040] On the bottom side of the processing container 12, an exhaust plate 48 is provided between the support portion 14 and the inner wall of the processing container 12. The exhaust plate 48 is constructed, for example, by coating aluminum with a ceramic such as Y2O3. An exhaust port 12e is provided below the exhaust plate 48 in the processing container 12. An exhaust device 50 is connected to the exhaust port 12e via an exhaust pipe 52. The exhaust device 50 includes a vacuum pump such as a turbomolecular pump. During plasma processing, the exhaust device 50 depressurizes the vacuum level inside the processing container 12 to the desired level. Additionally, a wafer W feed / outlet 12g is provided on the side wall of the processing container 12. The feed / outlet 12g can be opened and closed by a gate valve 54.

[0041] The operation of the plasma processing device 10 configured as described above is uniformly controlled by the control unit 100. The control unit 100, for example, is a computer, which controls each part of the plasma processing device 10. The operation of the plasma processing device 10 is uniformly controlled by the control unit 100.

[0042] In addition, the plasma processing device 10 has a circulation path in which the heating medium circulates in the temperature-controlled component. Figure 2 This is a diagram that roughly represents the conventional circulation path of the heating medium circulating in the nozzle 30 as a temperature control component. Figure 2 A schematic diagram shows the circulation path 110 for circulating brine in the nozzle 30 of the plasma treatment apparatus 10. The circulation path 110 is formed by a flow path 92, a conduit 111, and an external conduit 112. The flow path 92 is formed inside the nozzle 30 (support 36), and brine flows through the flow path 92. The conduit 111 is formed of a flexible resin and is disposed within the upper housing 12a. One end of the conduit 111 is connected to the flow path 92 inside the nozzle 30 via a connector 113a, and the other end of the conduit 111 is connected to one end of the external conduit 112 via a connector 114a provided in the upper housing 12a. The external conduit 112 is formed of a metal such as stainless steel and is disposed outside the upper housing 12a. One end of the external conduit 112 is connected to the conduit 111 via the connector 114a provided in the upper housing 12a, and the other end of the external conduit 112 is connected to a cooling unit 115.

[0043] The cooling unit 115 has a built-in water tank for storing brine. The water tank can control the stored brine to a desired temperature. The cooling unit 115 sends the brine stored in the water tank to one end of the circulation path 110, and recovers the brine flowing out from the other end of the circulation path 110 back to the water tank. Thus, the cooling unit 115 circulates the brine in the circulation path 110, thereby controlling the temperature of the nozzle 30 formed by the circulation path 110.

[0044] If the brine flows within the resin pipe 111, then as Figure 2As shown, the brine will be released as a gas through pipe 111 and around pipe 111. In particular, when the brine is controlled by cooling unit 115 to a temperature above 100°C, the brine tends to easily pass through pipe 111. Figure 2 The diagram shows brine being released as gas through pipe 111 within the upper housing 12a. When the upper housing 12a is removed for maintenance or other reasons, the released brine may diffuse into the cleanroom where the plasma treatment device 10 is installed, causing contamination within the cleanroom.

[0045] To address this, a plan was devised to use a tubular cover to airtightly surround the outer periphery of the resin pipe 111, connecting the exhaust pipe to the airtight space between the pipe 111 and the cover, allowing the brine released through the pipe 111 to be discharged through the exhaust pipe. However, when the brine is discharged from the exhaust pipe connected to the airtight space between the resin pipe 111 and the cover, the close proximity of the resin pipe 111 and the cover causes the space serving as the flow path for the brine to shrink, thus increasing the pressure loss in the space. Furthermore, it is difficult to place a pump near the upper casing 12a, therefore the exhaust pipe connecting the airtight space and the pump must be lengthened. As a result, there is a concern that the venting efficiency of the brine passing through the resin pipe 111 may decrease.

[0046] Therefore, in the case of the plasma processing apparatus 10 of this embodiment, an air supply port is provided in the cover surrounding the outer peripheral surface of the resin pipe 111, and air is supplied to the space between the pipe 111 and the cover in parallel with the discharge of the heat medium from the exhaust pipe.

[0047] Figure 3 and Figure 4 This is a schematic diagram illustrating the structure of the pipe 111 in the embodiment. The pipe 111 constitutes at least a portion of the circulation path 110 of the nozzle 30, which is a temperature-controlled object, through which brine, serving as a heat medium, circulates. The pipe 111 is formed of a highly flexible resin and is disposed within the upper housing 12a. One end of the pipe 111 is connected to the internal flow path 92 of the nozzle 30 via a connector 113a, and the other end of the pipe 111 is connected to one end of the external pipe 112 via a connector 114a provided in the upper housing 12a.

[0048] A tubular cover 131 is provided on the outer peripheral surface of the pipe 111 in a manner that surrounds the outer peripheral surface of the pipe 111. The cover 131 is formed of a resin with high flexibility. The resin forming the cover 131 may be the same as or different from the resin forming the pipe 111. A space is formed between the pipe 111 and the cover 131.

[0049] An exhaust pipe 132 is connected to the space between the pipe 111 and the cover 131. Specifically, the exhaust pipe 132 is connected to a blocking member 133 located at one end of the cover 131, which blocks the space between the pipe 111 and the cover 131, and communicates with the space between the pipe 111 and the cover 131 via a buffer space 133a formed in the blocking member 133. An exhaust mechanism is connected to the exhaust pipe 132. The exhaust mechanism can be an exhaust device 50 or another exhaust device besides the exhaust device 50. The permeable gas that passes through the pipe 111 and is released into the space between the pipe 111 and the cover 131 is discharged from the exhaust pipe 132.

[0050] Additionally, the cover 131 has an air supply port 131a, which supplies air to the space between the pipe 111 and the cover 131 in parallel with the exhaust gas from the exhaust pipe 132. Specifically, the cover 131 has an air supply port 131a on the opposite side from the side where the blocking member 133 is located. In this embodiment, the air supply port 131a is an open end formed by opening the other end of the cover 131. The cover 131 may also be shaped such that its width increases as it approaches the air supply port 131a. Furthermore, the air supply port 131a does not necessarily have to be an open end; it may also be a through hole that penetrates the cover 131 in the thickness direction. In addition, multiple air supply ports 131a may be provided on the other end of the cover 131. For example, both an open end air supply port 131a and a through hole air supply port 131a may be provided on the other end of the cover 131.

[0051] When venting permeable gas from the exhaust pipe 132, air is supplied from the air supply port 131a into the space between the pipe 111 and the cover 131. This suppresses the increase in pressure loss in the space between the pipe 111 and the cover 131. Furthermore, the air supplied from the air supply port 131a forces the permeable gas, which has passed through the pipe 111 and is released into the space between the pipe 111 and the cover 131, towards the exhaust pipe 132. As a result, the venting efficiency of the brine passing through the resin-made pipe 111 can be improved.

[0052] Furthermore, in the case of the plasma processing apparatus 10 of this embodiment, the pressure in the space where the pipe 111 and the cover 131 are arranged (i.e., the space surrounded by the upper housing 12a and the nozzle 30) is maintained at a positive pressure. For example, a fan 121 is provided in the upper housing 12a to supply external gas into the upper housing 12a, thereby making the pressure inside the upper housing 12a higher than the pressure outside the upper housing 12a. Alternatively, for example, a pressure gauge may be provided in the upper housing 12a to measure the pressure in the space surrounded by the upper housing 12a and the nozzle 30, and the air supply from the fan 121 may be controlled by the control unit 100 to make the pressure in this space a positive pressure. As a result, a large amount of air is supplied from the space where the pipe 111 and the cover 131 are arranged to the space between the pipe 111 and the cover 131 through the air supply port 131a of the cover 131, thereby further improving the exhaust efficiency of the permeable gas.

[0053] As described above, the plasma processing apparatus 10 of this embodiment includes a pipe 111 made of resin, which forms at least a portion of the circulation path for the heating medium circulating in the nozzle 30. The plasma processing apparatus 10 includes a cover 131 that surrounds the outer peripheral surface of the pipe 111; and an exhaust pipe 132 connected to the space between the pipe 111 and the cover 131, discharging the heating medium that passes through the pipe 111 and is released into that space. Furthermore, the cover 131 has an air supply port 131a that supplies air to the space between the pipe 111 and the cover 131 in parallel with the discharge of the heating medium from the exhaust pipe 132. Therefore, the plasma processing apparatus 10 can improve the exhaust efficiency of the heating medium (permeable gas) passing through the resin-made pipe 111. In addition, the plasma processing apparatus 10 can efficiently discharge the heating medium passing through the resin-made pipe 111, thus suppressing the amount of heating medium discharged to the outside of the plasma processing apparatus 10, thereby suppressing environmental pollution caused by the heating medium.

[0054] Furthermore, in the plasma processing apparatus 10, the exhaust pipe 132 is connected to a blocking member 133 located at one end of the cover 131, which blocks the space between the pipe 111 and the cover 131. The exhaust pipe 132 communicates with the space via a buffer space 133a formed in the blocking member 133. The cover 131 has an air supply port 131a at the other end, located opposite to the end where the blocking member 133 is located. Thus, the plasma processing apparatus 10 can allow air supplied from the air supply port 131a to the space between the pipe 111 and the cover 131 to flow from one end of the cover 131 to the other end, and under the action of the air, the heat medium is efficiently forced out toward the exhaust pipe 132.

[0055] It should be noted that the embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. The above embodiments may also be omitted, substituted, or modified in various forms without departing from the appended claims and their spirit.

[0056] For example, in Figure 3 and Figure 4 In the example shown, the cover is a tubular cover made of resin, but it is not limited to this. Figure 5 This is a diagram showing a variation of the cover. Figure 5 The example shown is an example where the upper housing 12a is used as a cover. A fan 121 is provided in the upper housing 12a as an air supply port, and an exhaust pipe 132 connected to an exhaust device is connected to the fan 121 at a position opposite to the fan 121. The air supplied from the fan 121 to the upper housing 12a flows toward the exhaust pipe 132, thus efficiently expelling the hot medium that has passed through the resin pipe 111 and is retained in the upper housing 12a.

[0057] For example, the plasma processing apparatus 10 described above is a CCP-type plasma etching apparatus, but the present invention can be applied to any plasma processing apparatus 10. For example, the plasma processing apparatus 10 can be applied to any of the following types: inductively coupled plasma (ICP), radial line slot antenna, electron cyclotron resonance plasma (ECR), and helicon wave plasma (HWP).

[0058] Furthermore, the above-described embodiment uses a substrate processing apparatus as an example of a plasma processing apparatus 10, but the present invention can also be applied to other semiconductor manufacturing apparatuses equipped with a cooling unit 115.

Claims

1. A heat medium circulation system, comprising: Pipes, made of resin, constitute at least a portion of the circulation path for the heating medium to circulate within the temperature-controlled object. A cover that surrounds the outer periphery of the pipe; An exhaust pipe, connected to the space between the pipe and the shroud, discharges the hot medium released through the pipe and into that space; and A housing that covers the object to be controlled by the temperature. The pipe and the cover are disposed within a space surrounded by the housing and the temperature-controlled object. The shroud has an air supply port that supplies air into the space between the pipe and the shroud in parallel with the discharge of the heat medium from the exhaust pipe. One end of the exhaust pipe is connected to a blocking member located at one end of the cover, which seals the space between the pipe and the cover. The exhaust pipe communicates with the space via a buffer space formed in the blocking member. The air supply port is located on the opposite end of the cover within the housing, on the side opposite to one end of the cover. The exhaust pipe has its other end located on the side opposite to one end of the exhaust pipe, positioned outside the space surrounded by the housing and the temperature-controlled object. The cover has a shape where its width increases as it gets closer to the air supply port. The air supply port is an open end formed by opening the other end of the cover.

2. The heat medium circulation system according to claim 1, wherein, The cover is a tubular component formed of resin.

3. The heat medium circulation system according to claim 1 or 2, wherein, The pressure within the space surrounded by the housing and the temperature-controlled object is maintained at a positive pressure.

4. The heat medium circulation system according to claim 1 or 2, wherein, The pipe is connected to a flow path formed inside the temperature-controlled object, allowing the heat medium to circulate within the flow path.

5. The heat medium circulation system according to claim 1 or 2, wherein, The heat medium is a liquid containing carbon.

6. A substrate processing apparatus comprising a heat medium circulation system, the heat medium circulation system having: Pipes, made of resin, constitute at least a portion of the circulation path for the heating medium to circulate within the temperature-controlled object. A cover that surrounds the outer periphery of the pipe; An exhaust pipe, connected to the space between the pipe and the shroud, discharges the hot medium released through the pipe and into that space; and A housing that covers the object to be controlled by the temperature. The pipe and the cover are disposed within a space surrounded by the housing and the temperature-controlled object. The shroud has an air supply port that supplies air into the space between the pipe and the shroud in parallel with the discharge of the heat medium from the exhaust pipe. One end of the exhaust pipe is connected to a blocking member located at one end of the cover, which seals the space between the pipe and the cover. The exhaust pipe communicates with the space via a buffer space formed in the blocking member. The air supply port is located on the opposite end of the cover within the housing, on the side opposite to one end of the cover. The exhaust pipe has its other end located on the side opposite to one end of the exhaust pipe, positioned outside the space surrounded by the housing and the temperature-controlled object. The cover has a shape where its width increases as it gets closer to the air supply port. The air supply port is an open end formed by opening the other end of the cover.

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