Refrigeration system

Abstract

To provide a refrigerating system capable of cooling to - 100 °C by improving efficiency of a device while suppressing enlargement of a device size.SOLUTION: The refrigeration system 1 is a refrigeration system used to cool a semiconductor, and includes an integrated turbomachine 10 in which a compressor 11 and an expander 12 are integrally formed via a motor shaft 13, a primary cooler 20 provided downstream of the compressor, a brine cooler 30 provided downstream of the expander, and a cold heat recovery heat exchanger 40 that exchanges cold heat of a refrigerant flowing downstream of the brine cooler and hot heat of a refrigerant flowing downstream of the primary cooler.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to refrigeration systems. [Background technology]

[0002] BACKGROUND ART Conventionally, semiconductor chillers for cooling semiconductors use a vapor compression refrigeration cycle that involves a phase change (evaporation / condensation) of a refrigerant (for example, Patent Document 1 listed below).

[0003] In particular, when cooling to temperatures below -50°C, a two-stage or three-stage refrigeration system is used, which uses fluorocarbons such as R23 and R404A as refrigerants. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent 6624623 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, with the increasing demand for miniaturization of semiconductors, etching of semiconductors is required to be carried out at ultra-low temperatures, for example, -100°C. However, fluorocarbons such as R23 can only lower the temperature to -80°C.

[0006] Furthermore, in the case of the above-mentioned two-way refrigeration system and three-way refrigeration system, a plurality of compressors are required, which increases the overall power consumption of the compressors and reduces efficiency.

[0007] Furthermore, in the case of the above-mentioned two-way refrigeration system and three-way refrigeration system, since the refrigerant undergoes a phase change, a gas-liquid separator and a liquid receiver are required, which may increase the size of the system.

[0008] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a refrigeration system that can cool down to -100°C by improving the efficiency of the device while suppressing an increase in device size. [Means for solving the problem]

[0009] The above object of the present invention can be achieved by the following means.

[0010] A refrigeration system used for cooling semiconductors, comprising: an integrated turbomachine in which a compressor and an expander are integrally configured via a motor shaft; a primary cooler provided downstream of the compressor; a brine cooler provided downstream of the expander; a cold heat recovery heat exchanger that exchanges cold heat of the refrigerant flowing downstream of the brine cooler with hot heat of the refrigerant flowing downstream of the primary cooler. [Effects of the Invention]

[0011] According to the refrigeration system of the present invention, since it is a refrigeration system employing a gas cycle method, it is possible to cool down to -100°C. Furthermore, since it is a refrigeration system employing a gas cycle method, a gas-liquid separator and a liquid receiver are not required, and an increase in the size of the equipment can be suppressed. Furthermore, since only one compressor is required, power consumption is small and efficiency can be improved. From the above, it is possible to provide a refrigeration system that can cool down to -100°C by improving the efficiency of the equipment while suppressing an increase in the size of the equipment. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a system diagram showing a refrigeration system according to an embodiment of the present invention. [Figure 2] FIG. 1 is a system diagram showing a cascade refrigeration system according to a comparative example. [Figure 3] FIG. 10 is a system diagram showing a refrigeration system according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of the present invention will be described below with reference to Fig. 1. In the description of the drawings, the same elements are given the same reference numerals, and duplicate explanations will be omitted. Also, the dimensional proportions in the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions. Fig. 1 is a system diagram showing a refrigeration system according to an embodiment of the present invention.

[0014] As shown in FIG. 1, the refrigeration system 1 includes an integrated turbomachine 10 in which a compressor 11 and an expander 12 are integrally configured, a primary cooler 20 provided downstream of the compressor 11, a brine cooler 30 provided downstream of the expander 12, and a cold energy recovery heat exchanger 40 that exchanges heat downstream of the primary cooler 20 and downstream of the brine cooler 30.

[0015] Nitrogen or air can be used as the refrigerant circulating in the refrigeration system 1 according to this embodiment. Because a fluorocarbon-based refrigerant such as fluorocarbon is not used as the refrigerant, the refrigeration system 1 is exempt from the application of the Fluorocarbons Emission Prevention Act, and no specialized knowledge or tools are required.

[0016] The refrigeration system 1 according to this embodiment is a gas cycle system known as a reverse Brayton cycle. The refrigeration system 1 according to this embodiment is a gas cycle system, and since it controls gas, a gas-liquid separator and a liquid receiver are not required.

[0017] The integrated turbomachine 10 is configured such that a compressor 11 and an expander 12 are integrated via a motor shaft 13. The compressor 11 compresses air using the energy generated by rotating an impeller at high speed. The compressor 11 is driven by electricity, but when expanding the compressed air, the adiabatic expansion that occurs in the expander 12 can be used as auxiliary power for the compressor 11 via the motor shaft 13. This allows the efficiency of the refrigeration system 1 to be improved.

[0018] The bearing of the motor shaft 13 of the integrated turbomachinery 10 is a non-contact magnetic bearing. If, for example, a ball bearing were used as the bearing, sliding parts would be generated, shortening maintenance intervals and making maintenance more complicated. Furthermore, refrigeration oil would be required, which could cause compressor failure.

[0019] In contrast, in the refrigeration system 1 according to this embodiment, the bearing of the motor shaft 13 of the integrated turbo machine 10 is a non-contact magnetic bearing, eliminating sliding parts and facilitating maintenance. Furthermore, since refrigeration oil is not required, compressor breakdowns are less likely to occur and a decrease in heat transfer performance due to refrigeration oil can be prevented. Furthermore, the equipment for lubricating the refrigeration oil can be omitted, allowing for vertical installation, reducing the installation area.

[0020] The flow of the refrigeration system 1 according to this embodiment will be described below, taking as an example a case where air is used as the refrigerant.

[0021] In the brine cooler 30, the air is cooled to -60°C at atmospheric pressure after heat exchange with the brine flowing through the secondary line 51 in which the object to be cooled 50 is placed, and then in the cold heat recovery heat exchanger 40, the air is cooled to 35°C by heat exchange with the 40°C air that has flowed through the primary cooler 20. A brine pump and tank (not shown) are placed in the secondary line 51.

[0022] The 35°C air is compressed and heated in the compressor 11 of the integrated turbomachine 10 to become air at 90°C. The 90°C air dissipates heat to 40°C in the primary cooler 20 by water cooled by the cooling tower 60.

[0023] As described above, the 40°C air exchanges heat with the -60°C air that has flowed through the brine cooler 30 in the cold heat recovery heat exchanger 40, and is cooled to -55°C. The -55°C air is adiabatically expanded on the expander 12 side of the integrated turbomachine 10, becoming cold air of -80°C, which then exchanges heat with the brine circulating through the secondary line 51 in the brine cooler 30, cooling the brine, which then cools the object to be cooled.

[0024] In this embodiment, the object to be cooled in the secondary line 51 is a semiconductor, and is used particularly for cooling during etching of the semiconductor.

[0025] Next, the configuration of a cascade refrigeration system 900 according to a comparative example will be described with reference to Fig. 2. The cascade refrigeration system 900 is a refrigeration system that uses two types of refrigerants with different boiling points, each circulating through an independent refrigeration cycle and connected by a heat exchanger.

[0026] As shown in FIG. 2, the cascade refrigeration system 900 has a high-temperature side refrigeration cycle 910 and a low-temperature side refrigeration cycle 920.

[0027] Each of the refrigeration cycles 910 and 920 is a known refrigeration cycle, and as shown in Fig. 2, the high-temperature side refrigeration cycle 910 has a high-temperature compressor 911, a high-temperature side condenser 912, a high-temperature side receiver 913, a high-temperature side expansion valve 914, a high-temperature side evaporator 915, and a high-temperature side gas-liquid separator 916. As shown in Fig. 2, the low-temperature side refrigeration cycle 920 has a low-temperature compressor 921 , a low-temperature side condenser 922 , a low-temperature side receiver 923 , a low-temperature side expansion valve 924 , a low-temperature side evaporator 925 , and a low-temperature side gas-liquid separator 926 .

[0028] In the cascade refrigeration system 900, heat exchange occurs in the high-temperature side evaporator 915 and the low-temperature side condenser 922. Although not shown, heat exchange occurs with brine flowing through the secondary line in the low-temperature side evaporator 925 of the low-temperature side refrigeration cycle 920. In other words, the low-temperature side evaporator 925 of the low-temperature side refrigeration cycle 920 serves as a brine cooler.

[0029] Below, the issues of the two-cascade refrigeration system 900 and the three-cascade refrigeration system (not shown) and the effects of the refrigeration system 1 according to this embodiment on the issues will be described in order.

[0030] <First issue and effect> In the case of a two-cascade refrigeration system 900 or a three-cascade refrigeration system, multiple compressors are required, which increases the overall power consumption of the compressors and results in poor efficiency. In contrast, the refrigeration system 1 according to this embodiment uses only one compressor, which reduces power consumption and results in good efficiency.

[0031] <Second issue and effect> In the case of the binary refrigeration system 900 or the ternary refrigeration system, a gas-liquid separator and a liquid receiver are required because a phase change occurs, resulting in a large device size. In contrast, in the case of the refrigeration system 1 according to this embodiment, there is no phase change from gas, so a gas-liquid separator and a liquid receiver are not required, allowing for a smaller device size.

[0032] <Third issue and effect> In the case of the cascade refrigeration system 900 or the cascade refrigeration system, the installation direction of the compressor is restricted due to the vibration of the compressor, resulting in a large installation area. In contrast, in the case of the refrigeration system 1 according to this embodiment, magnetic bearings are used for the compressor and expander to make them non-contact, which allows for vertical installation and reduces the installation area.

[0033] <Fourth issue and effect> In the case of a cascade refrigeration system 900 or a cascade refrigeration system, multiple expansion valves are used, and the controls of each stage interfere with each other, making hunting more likely to occur and difficult to control. In contrast, the refrigeration system 1 according to this embodiment is easy to control because it can be controlled simply by controlling the rotation speed of the integrated turbomachinery 10. Furthermore, because it controls gas, the time constant is fast and control accuracy is high. Furthermore, because the heat capacity of the cold energy recovery heat exchanger 40 is large, the capacity control responds quickly to load fluctuations.

[0034] <Fifth issue and effect> In the case of the two-cascade refrigeration system 900 or the three-cascade refrigeration system, the Fluorocarbon Emission Prevention Act applies because a refrigerant with a large environmental load is used, and specialized knowledge and tools are required for refrigerant recovery. In contrast, the refrigeration system 1 according to this embodiment uses an inert gas, so the Fluorocarbon Emission Prevention Act does not apply, and specialized knowledge and tools are not required.

[0035] <6th issue and effect> In the case of a two-cascade refrigeration system 900 or a three-cascade refrigeration system, there are many sliding parts, and maintenance intervals are short and maintenance is complicated. Furthermore, refrigeration oil is used, which is likely to cause compressor failure. In contrast, in the case of the refrigeration system 1 according to this embodiment, the use of a non-contact magnetic bearing reduces the number of sliding parts in the machine, so maintenance intervals are long and maintenance is simple. Furthermore, there is no reduction in heat transfer performance due to refrigeration oil.

[0036] <Seventh issue and effect> In the case of the cascade refrigeration system 900 or the cascade refrigeration system, when intermittently cooling semiconductors, stopping the refrigeration system once results in a slow start-up, so it is necessary to continue rotating at a low rotation speed. However, since the rotation speed cannot be reduced too much, a heater is placed in the secondary cooling circuit and the system is operated under a simulated load. This results in poor efficiency in the cascade refrigeration system 900 or the cascade refrigeration system. In contrast, the refrigeration system 1 according to this embodiment controls the rotation speed of the integrated turbomachinery 10 to perform capacity control, allowing the system to be in standby mode at a low rotation speed, improving efficiency. For example, the COP value is 0.25 at 70°C for the cascade refrigeration system 900 or the cascade refrigeration system, and 0.36 at 70°C for the refrigeration system 1 according to this embodiment.

[0037] As described above, the refrigeration system 1 according to this embodiment is a refrigeration system used for cooling semiconductors. The refrigeration system 1 includes an integrated turbomachine 10 in which a compressor 11 and an expander 12 are integrated via a motor shaft 13, a primary cooler 20 provided downstream of the compressor 11, a brine cooler 30 provided downstream of the expander 12, and a cold heat recovery heat exchanger 40 that exchanges cold energy from a refrigerant flowing downstream of the brine cooler 30 with hot energy from a refrigerant flowing downstream of the primary cooler 20. The refrigeration system 1 configured in this manner employs a gas cycle system, enabling cooling down to -100°C. Furthermore, because it employs a gas cycle system, a gas-liquid separator and a liquid receiver are not required, thereby minimizing the device size. Furthermore, since only one compressor is required, power consumption is reduced, improving efficiency. As described above, a refrigeration system capable of cooling down to -100°C can be provided, improving the device efficiency while minimizing device size.

[0038] The refrigerant is nitrogen or air. Since the refrigeration system 1 configured in this manner does not use a fluorocarbon-based refrigerant such as fluorocarbon, it is not subject to the Fluorocarbon Emission Prevention Act and does not require specialized knowledge or tools.

[0039] Furthermore, capacity control is performed by controlling the rotation speed of the integrated turbo machine 10. According to the refrigeration system 1 configured in this manner, it is possible to put the system into a standby state at a low rotation speed, thereby improving efficiency.

[0040] The bearing of the motor shaft 13 is a non-contact magnetic bearing. With the refrigeration system 1 configured in this way, there are no sliding parts, making maintenance easier. Also, since refrigeration oil is no longer required, compressor breakdowns are less likely to occur and degradation of heat transfer performance due to refrigeration oil can be prevented. Furthermore, equipment for lubricating the refrigeration oil can be omitted, allowing for vertical installation and reducing the installation area.

[0041] As described above, the refrigeration system 1 according to this embodiment has been described. However, it goes without saying that those skilled in the art can make appropriate additions, modifications, and omissions to the present invention within the scope of the technical concept thereof.

[0042] During semiconductor etching, it is preferable to switch between ultra-low and high temperatures depending on the gas to be converted into plasma. The refrigeration system 1 according to the above-described embodiment can accommodate ultra-low temperatures. As shown in FIG. 3 , a refrigeration system 2 according to a modified example may further include a path L that recovers heat from the refrigerant heated by the compressor 11 and supplies it to the heater H side of the secondary equipment in the primary cooler 20. With the refrigeration system 1 configured in this manner, the heat from the refrigerant heated by the compressor 11 can be effectively utilized to appropriately heat the semiconductor to be heated 70. While FIG. 3 illustrates a configuration in which the semiconductor to be cooled 50 and the semiconductor to be heated 70 are different, the semiconductor to be cooled 50 and the semiconductor to be heated 70 may be the same. With this configuration, during semiconductor etching, it is possible to switch between ultra-low and high temperatures depending on the gas to be converted into plasma. [Explanation of symbols]

[0043] 1, 2 refrigeration system, 10 integral turbomachinery, 11 compressor, 12 Expander, 13 motor shaft, 20 primary cooler, 30 Brine Cooler, 40 Cold recovery heat exchanger.

Claims

1. A refrigeration system used for cooling semiconductors, comprising: an integrated turbomachine in which a compressor and an expander are integrally configured via a motor shaft; a primary cooler provided downstream of the compressor; a brine cooler provided downstream of the expander; a cold heat recovery heat exchanger that exchanges cold heat of the refrigerant flowing downstream of the brine cooler with hot heat of the refrigerant flowing downstream of the primary cooler.

2. 2. The refrigeration system of claim 1, wherein the refrigerant is nitrogen or air.

3. 3. The refrigeration system according to claim 1, wherein capacity control is performed by controlling the rotational speed of the integrated turbomachine.

4. The refrigeration system according to claim 1 or 2, wherein the bearing of the motor shaft is a non-contact magnetic bearing.

5. The refrigeration system according to claim 1 or 2, further comprising a path for recovering heat from the refrigerant heated by the compressor and supplying the recovered heat to a heater side of secondary equipment.

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