Cooling device, semiconductor manufacturing device and semiconductor manufacturing method

Abstract

To provide a cooling device advantageous for cooling a cooling object.SOLUTION: A cooling device for cooling a cooling object has a circulation system for making a refrigerant for cooling the cooling object circulate, and the circulation system is provided with a vessel including a region in which heat is exchanged between at least a part of the cooling object and the refrigerant. The refrigerant is a mixed refrigerant which is obtained by mixing a first refrigerant having a first boiling point and a second refrigerant having a second boiling point which is higher than the first boiling point. The circulation system makes the mixed refrigerant circulate so that both the first refrigerant and the second refrigerant are exposed to the mixed refrigerant in a liquid phase state in an entire area of the region, and the mixed refrigerant in an air / liquid mixed-phase state is discharged from the vessel.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cooling device, a semiconductor manufacturing apparatus, and a semiconductor manufacturing method.

Background Art

[0002] Semiconductor manufacturing apparatuses such as pattern forming apparatuses such as exposure apparatuses, imprint apparatuses, and electron beam drawing apparatuses, or plasma processing apparatuses such as CVD apparatuses, etching apparatuses, and sputtering apparatuses have heat generating parts such as drive mechanisms or members heated by plasma. In order to cool such heat generating parts, a cooling device is provided in the semiconductor manufacturing apparatus. The cooling device cools the heat generating part by taking heat from the heat generating part and dissipating such heat outside the apparatus.

[0003] Patent Document 1 discloses a cooling system having an evaporator that extracts heat from components, a condenser, a pump, an accumulator, a heat exchanger, and a temperature sensor. In such a cooling system, a circulation path is formed in which the fluid refrigerant discharged from the pump returns to the pump via the evaporator and the condenser, and the accumulator is in fluid communication with the circulation path. The heat exchanger transfers heat from the fluid refrigerant in the accumulator and transfers heat to the fluid refrigerant in the accumulator. At this time, the amount of heat transfer is controlled based on the output of the temperature sensor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In cooling systems that circulate liquid refrigerants using pumps, refrigerants with a boiling point at atmospheric pressure above room temperature that do not require liquefaction (e.g., HFO-1336mzz(E), Novec7000, HFO-1233zd(Z)) are commonly used. If the boiling temperature is to be set lower than the boiling point at atmospheric pressure using such refrigerants, the vapor pressure will be lower than atmospheric pressure.

[0006] Considering a linear motor with a jacket structure in which the coil is placed inside a sealed container and the internal space is filled with a fluid coolant to cool the coil, the boiling vaporized coolant flows to the upper part of the internal space of the jacket due to the density difference. As the heat generated by the coil increases, the amount of vaporized coolant also increases, and because the pressure is low, the vaporized coolant occupies the internal space of the jacket. As a result, the upper part of the coil, which is the heat-generating part, is covered by the vaporized coolant, and boiling cooling cannot occur, a condition known as dry-out. When dry-out occurs, the temperature of the coil rises rapidly, and the coil burns out.

[0007] One might consider supplying a sufficient amount (flow rate) of refrigerant to boil-cool the coils generating heat within the jacket's internal space. However, if the internal pressure is low, the vaporized refrigerant will expand and occupy the upper part of the jacket's internal space, making it impossible to prevent dry-out. It is possible to prevent dry-out by further increasing the refrigerant flow rate and pushing the vaporized medium through. However, in this case, it becomes equivalent to convection cooling, and the advantage of boil-cooling, which allows for the recovery of a large amount of heat at a low flow rate, cannot be enjoyed. This leads to pressure resistance problems due to the increased refrigerant flow rate, larger equipment size, and increased energy consumption.

[0008] This invention has been made in view of the problems of the prior art, and its exemplary objective is to provide a cooling device that is advantageous for cooling an object to be cooled. [Means for solving the problem]

[0009] To achieve the above objective, a cooling device as one aspect of the present invention is a cooling device for cooling an object to be cooled, having a circulation system for circulating a refrigerant for cooling the object to be cooled, the circulation system being provided with a container including a region in which heat exchange takes place between at least a part of the object to be cooled and the refrigerant, the refrigerant being a mixed refrigerant obtained by mixing a first refrigerant having a first boiling point and a second refrigerant having a second boiling point higher than the first boiling point, and the circulation system circulating the mixed refrigerant such that the entire region is exposed to the mixed refrigerant in which both the first and second refrigerants are in the liquid phase, and the mixed refrigerant in a gas-liquid mixed phase is discharged from the container.

[0010] Further objects or other aspects of the present invention will be revealed by embodiments described below with reference to the accompanying drawings. [Effects of the Invention]

[0011] According to the present invention, for example, it is possible to provide a cooling device that is advantageous for cooling an object to be cooled. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing the configuration of a cooling device in the first embodiment of the present invention. [Figure 2] This figure shows an example of a saturated vapor pressure curve for a refrigerant. [Figure 3] This figure shows the saturated vapor pressure curves of low-boiling-point refrigerants and the saturated vapor pressure curves of mixed refrigerants. [Figure 4] This is a schematic diagram showing the configuration of a cooling device in a second embodiment of the present invention. [Figure 5] This is a schematic diagram showing the configuration of a cooling device in a third embodiment of the present invention. [Figure 6A] This is a schematic diagram showing the configuration of a cooling device in a fourth embodiment of the present invention. [Figure 6B] This is a schematic diagram showing the configuration of a cooling device in a fourth embodiment of the present invention. [Figure 6C]It is a schematic diagram showing the configuration of the cooling device in the fourth embodiment of the present invention. [Figure 7] It is a schematic diagram showing the configuration of the exposure device. [Figure 8] It is a schematic diagram showing the configuration of the imprint device. [Figure 9] It is a schematic diagram showing the configuration of the plasma processing device.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential to the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are given the same reference numerals, and duplicate explanations are omitted.

[0014] <First Embodiment> FIG. 1 is a schematic diagram showing the configuration of the cooling device CA1 in the first embodiment of the present invention. The object to be cooled by the cooling device CA1 is not limited to a special object. For example, it is a semiconductor manufacturing device, particularly, the heat-generating part of a semiconductor manufacturing device. The semiconductor manufacturing device includes, for example, pattern forming devices such as exposure devices, imprint devices, and electron beam lithography devices, or plasma processing devices such as CVD devices, etching devices, and sputtering devices. The pattern forming device has a drive mechanism for driving components such as a substrate and / or a reticle at high speed, and such a drive mechanism generates heat due to the driving of the components, thus becoming a heat-generating part. In the plasma processing device, components such as electrodes are heated by plasma, so such components become heat-generating parts.

[0015] The cooling device CA1 is configured to cool a cooling object 80 such as a heat generating part. As shown in FIG. 1, the cooling device CA1 has a refrigerant circulation system 1 provided with a condenser 2, a pump 3, a heater 4, a temperature sensor 5, a throttle valve 6, and a heat exchange container 7. The refrigerant circulation system 1 (cooling device CA1) constitutes a closed circulation system in which the cooling object 80, which is a heat generating part, is accommodated in the heat exchange container 7 (inside). In the present embodiment, the entire cooling object 80 is accommodated in the heat exchange container 7, but it is not limited thereto, and at least a part of the cooling object 80 may be accommodated in the heat exchange container 7. Here, the refrigerant 10 circulating in the refrigerant circulation system 1 is a mixed refrigerant obtained by mixing a low-boiling refrigerant 11 (first refrigerant with a first boiling point) and a high-boiling refrigerant 12 (second refrigerant with a second boiling point higher than the first boiling point), specifically, azeotropic mixed refrigerant.

[0016] The liquid-phase refrigerant 10 (hereinafter referred to as "liquid refrigerant 14") accommodated in the condenser 2 (inside) is sent to the heater 4 by the pump 3. Thus, the pump 3 has a function of sending out the liquid refrigerant 14 (mixed refrigerant) from the condenser 2. The heater 4 heats the liquid refrigerant 14 sent from the pump 3 so that the refrigerant temperature detected by the temperature sensor 5 provided downstream of the heater 4 becomes a predetermined control temperature. The heater 4 includes, for example, an electric heater or a heat exchanger for heating (temperature control) the liquid refrigerant 14, but is not limited thereto.

[0017] The liquid refrigerant 14 temperature-controlled to the control temperature is decompressed in the throttle valve 6 until the low-boiling refrigerant 11 reaches near the saturated vapor pressure at the control temperature and is sent to the heat exchange container 7. Thus, the throttle valve 6 functions as a decompressor that decompresses the liquid refrigerant 14 sent from the pump 3 and supplies it to the heat exchange container 7.

[0018] The heat exchange container 7 includes a heat exchange region 72 that exchanges heat with the object to be cooled 80, and the object to be cooled 80 is housed within the heat exchange region 72. When the object to be cooled 80 housed within the heat exchange container 7 generates heat, the low-boiling-point refrigerant 11 of the liquid refrigerant 14 (mixed refrigerant) supplied to the heat exchange container 7 boils and cools the object to be cooled 80 with its latent heat of vaporization, while the high-boiling-point refrigerant 12 cools the object to be cooled 80 by convection. In this way, the low-boiling-point refrigerant 11 boils and cools the object to be cooled 80 in the heat exchange region 72 within the heat exchange container, becoming a gaseous state, while the high-boiling-point refrigerant 12 cools the object to be cooled 80 by convection in a liquid state within the heat exchange region 72 within the heat exchange container. The low-boiling-point refrigerant 11 that passes through the heat exchange region 72 within the heat exchange container and is discharged from the heat exchange container 7 is returned to the condenser 2 in a liquid state or a gas-liquid mixed-phase (two-phase) state, depending on the heat generation state of the object to be cooled 80. On the other hand, the high-boiling-point refrigerant 12 that passes through the heat exchange region 72 in the heat exchange vessel and is discharged from the heat exchange vessel 7 is always returned to the condenser 2 in liquid phase, regardless of the exothermic state of the object being cooled 80.

[0019] In this embodiment, the condenser 2 condenses the gas-liquid mixed refrigerant 10 (mixed refrigerant) discharged from the heat exchange vessel 7 into liquid refrigerant 14. The condenser 2 is equipped with a heat exchanger 8 and a pressure sensor 9. The condenser 2 controls the heat generation to the outside of the refrigerant circulation system 1 via the heat exchanger 8 so that the pressure detected by the pressure sensor 9 is always at a predetermined pressure.

[0020] Here, the boiling point inside the heat exchange container 7 is determined by controlling the pressure of the low-boiling-point refrigerant 11 inside the heat exchange container 7 to be equal to the saturated vapor pressure at the controlled temperature. In the case of boiling cooling, heat is recovered by the latent heat of vaporization, so a large amount of heat can be recovered with a small refrigerant flow rate and at a constant temperature.

[0021] When the low-boiling-point refrigerant 11 boils and vaporizes, it becomes a gaseous refrigerant (hereinafter referred to as "gaseous refrigerant 13"), and due to the density difference with the high-boiling-point refrigerant 12, it floats up and occupies the upper space of the heat exchange container 7. However, in this embodiment, a predetermined amount of high-boiling-point refrigerant 12 (liquid refrigerant 14) is always present in the heat exchange container, and the high-boiling-point refrigerant 12 passes through the object to be cooled 80 while maintaining its liquid phase state. In other words, in this embodiment, the high-boiling-point refrigerant 12 in liquid phase is present from the upstream side to the downstream side of the object to be cooled 80. As a result, the exposure time of the object to be cooled 80 to the gaseous refrigerant 13 is reduced, and the occurrence of a state in which the object to be cooled 80 (or its upper part) is covered by the gaseous refrigerant 13 and boiling cooling cannot be performed, so-called dry-out, can be suppressed.

[0022] Furthermore, if the object to be cooled 80 is a coil (coil train) of a linear motor, grooves exist between the wires on its surface. Due to capillary action, the high-boiling-point refrigerant 12 in liquid phase enters the grooves on the coil surface, and the low-boiling-point refrigerant 11 in liquid phase is also guided to the grooves on the coil surface. This promotes boiling cooling of the object to be cooled 80 and suppresses the occurrence of dry-out.

[0023] However, if the object to be cooled 80 generates a large amount of heat and a refrigerant with a low vapor pressure under controlled temperature is used as the low-boiling-point refrigerant 11, the upper part of the object to be cooled 80 will be exposed to the gaseous refrigerant 13, and the cooling effect of the high-boiling-point refrigerant 12 alone will not be sufficient to suppress the occurrence of dryout.

[0024] To suppress the occurrence of dryout, a refrigerant with a high vapor pressure under controlled temperature should be used as the low-boiling-point refrigerant 11. This compresses the gaseous refrigerant 13 that has lost its cooling capacity, reducing the volume occupied by the gaseous refrigerant 13 and making it easier for the object to be cooled 80 to be exposed to the liquid refrigerant 14.

[0025] Furthermore, if the object to be cooled 80 is a linear motor with a jacket structure, in order to increase thrust, it is necessary to bring the coil inside the jacket closer to the magnet outside the jacket and shorten the distance between the coil and the magnet. Because the jacket has a thin-walled structure that allows magnetic force to pass through, its pressure resistance is on the order of 100 kPa. Refrigerants such as R32, which are commonly used in refrigeration cycles, have vapor pressures on the order of MPa, and therefore cannot be used when the object to be cooled 80 is a linear motor with a jacket structure. Also, while it is desirable to increase the vapor pressure of the refrigerant as much as possible within the pressure resistance range, selecting such a refrigerant is extremely difficult.

[0026] Therefore, in this embodiment, a non-azeotropic mixed refrigerant, which is a mixture of a low-boiling-point refrigerant 11 and a high-boiling-point refrigerant 12, is used as the refrigerant for cooling the object to be cooled 80, and the physical phenomenon of raising the boiling point of the low-boiling-point refrigerant 11 is utilized.

[0027] Figure 2 shows an example of a saturated vapor pressure curve for a refrigerant. In Figure 2, the horizontal axis represents temperature T [K], and the vertical axis represents vapor pressure P [Pa]. The saturated vapor pressure curve of a refrigerant is determined by the physical properties of the refrigerant and is expressed by the following Clausius-Clapeyron equation, resulting in an upward-sloping curve as shown in Figure 2. dP / dT = L / (Vv-Vl) / Ts Note that dP: pressure change, dT: temperature change, L: latent heat, Vv: vapor specific volume, Vl: liquid specific volume, and Ts: saturation temperature.

[0028] When a high-boiling-point refrigerant 12 is mixed with a low-boiling-point refrigerant 11, the boiling point elevation (ΔT) can be expressed by the following equation, assuming that the high-boiling-point refrigerant 12 is non-volatile. ΔT ≈ xs·R(T*) 2 / Lm Note that ΔT is defined as the boiling point elevation, R as the gas constant, T* as the boiling point of the low-boiling pure refrigerant, xs as the mole fraction of the high-boiling refrigerant, and Lm as the latent heat of vaporization of the mole of low-boiling refrigerant.

[0029] Referring to Figure 2, raising the boiling point of the low-boiling-point refrigerant 11 is equivalent to shifting the saturated vapor pressure curve parallel to the high-temperature side (to the right), and under controlled temperatures, this lowers the vapor pressure of the low-boiling-point refrigerant 11. Therefore, the vapor pressure can be adjusted by adjusting the mixing ratio of the low-boiling-point refrigerant 11 and the high-boiling-point refrigerant 12.

[0030] For example, consider the case where the controlled temperature is 23 degrees Celsius and the pressure resistance of the heat exchange container 7 is 400 kPa-abs. Furthermore, as the low-boiling point refrigerant 11, we will use R-1234zeE (vapor pressure at 23 degrees Celsius: 450 kPa), whose vapor pressure at the controlled temperature is slightly higher than the pressure resistance of the heat exchange container 7. Note that R-1234yf can also be used as the low-boiling point refrigerant 11.

[0031] Figure 3 shows the saturated vapor pressure curve of R-1234zeE as a low boiling point refrigerant 11, and the saturated vapor pressure curve of a mixed refrigerant whose vapor pressure reaches the pressure limit (400 kPa) under controlled temperature. In Figure 3, the horizontal axis represents temperature [°C] and the vertical axis represents vapor pressure [kPa]. Referring to Figure 3, it is necessary to raise the boiling point by approximately 4 degrees. To achieve a 4-degree boiling point increase, substituting the physical properties of R-1234zeE into the boiling point elevation (ΔT) equation described above, it can be seen that the high-boiling point refrigerant 12 should be mixed in such a way that its mole fraction is approximately 0.2. Here, it is preferable that the high-boiling point refrigerant 12 has affinity for the low-boiling point refrigerant 11 and has a sufficiently low saturated vapor pressure under controlled temperature.

[0032] Furthermore, increasing the vapor pressure of the low-boiling-point refrigerant 11 can reduce the bubble diameter of the gaseous refrigerant 13 produced by boiling cooling. If the bubble internal pressure is Pv, the liquid pressure is Pl, the bubble diameter is r, and the surface tension is σ, then the following equation holds true from the equilibrium of forces in the bubble. Pv = Pl + 2σ / r From this equation, the internal pressure of the bubble is higher than the surrounding liquid by a pressure of ΔP = 2σ / r.

[0033] Furthermore, at the bubble interface, the liquid becomes superheated above its saturation temperature. Applying the Clausius-Clapeyron equation between the bubble and the liquid, with Tl being the superheated liquid temperature, Ps being the saturated vapor pressure at the superheated liquid temperature, and Ts being the saturation temperature at the liquid pressure Pl, the following equation holds: (Pv-Pl) / (Tl-Ts)=L / (Vv-Vl) / Ts Here, if we approximate Vv >> Vl and Pv ≈ Ps, the following equation holds. ΔP = Pv - Pl ≈ L(Tl - Ts) / Vv / Ts According to Boyle's Law, Vv is inversely proportional to Pl, and given the properties of R-1234ZeE and the allowance for a few degrees of superheating, a differential pressure of approximately 100 kPa can be generated. Combined with the increase in vapor pressure, this can compress the bubbles to about 1 / 5 of their original size relative to atmospheric pressure.

[0034] If a refrigerant with a large latent heat of vaporization is used as the low-boiling point refrigerant 11, the vapor volume can be further reduced, and the amount of gaseous refrigerant 13 can be reduced. R-1234ZeE has a latent heat of 195.4 J / g. Thus, because R-1234ZeE is a refrigerant with a relatively high latent heat, it is suitable for dry-out countermeasures and is also environmentally friendly with a global warming potential (GWP) of 6.

[0035] Thus, in this embodiment, in the refrigerant circulation system 1, the entire heat exchange region 72 of the heat exchange container 7 is exposed to a mixed refrigerant consisting of both a low-boiling-point refrigerant 11 and a high-boiling-point refrigerant 12 in a liquid phase state, and the mixed refrigerant is circulated so that a mixed refrigerant in a gas-liquid mixed phase state is discharged from the heat exchange container 7. To achieve this, the mixed refrigerant is mixed in the heat exchange container in such a ratio that the low-boiling-point refrigerant 11 boils and cools the object to be cooled 80 to a gas phase state, while the high-boiling-point refrigerant 12, in a liquid phase state, convectually cools the object to be cooled 80 and compresses the low-boiling-point refrigerant 11 in a gas phase state.

[0036] Specifically, a non-azeotropic mixed refrigerant is used as the refrigerant mixture, and the mixing ratio of the low-boiling-point refrigerant 11 and the high-boiling-point refrigerant 12 is adjusted to increase the vapor pressure of the low-boiling-point refrigerant 11 to near the pressure resistance of the heat exchange container 7. This allows the low-boiling-point refrigerant in the gas phase generated by boiling cooling to be compressed. In addition, the bubble diameter of the low-boiling-point refrigerant in the gas phase becomes smaller, and the internal pressure of the bubbles increases by the curvature ratio of the bubbles compared to the surrounding liquid. This allows for further compression of the low-boiling-point refrigerant in the gas phase generated by boiling cooling. Due to this compression effect, the proportion of the volume occupied by the liquid-phase low-boiling-point refrigerant, which has lost its cooling capacity, in the heat exchange container is reduced, thus suppressing the occurrence of dry-out.

[0037] <Second Embodiment> Figure 4 is a schematic diagram showing the configuration of the cooling device CA2 in the second embodiment of the present invention. The cooling device CA2 in this embodiment applies the cooling device CA1 (circulation of liquid refrigerant by a pump) of the first embodiment to a general refrigeration cycle in which gaseous refrigerant is circulated by a compressor. Matters not mentioned in this embodiment are the same as in the first embodiment.

[0038] The cooling device CA2 is configured to cool an object to be cooled, such as a heat-generating part, 80. As shown in Figure 4, the cooling device CA2 has a refrigerant circulation system 21 which includes a compressor 22, a condenser 23, an expansion valve 24, and a heat exchange container 25. The refrigerant circulation system 21 (cooling device CA2) constitutes a closed circulation system in which the object to be cooled 80, which is a heat-generating part, is housed inside the heat exchange container 25. In this embodiment, the entire object to be cooled 80 is housed in the heat exchange container 25, but this is not limited to this, and at least a part of the object to be cooled 80 may be housed in the heat exchange container 25. Here, the refrigerant 10 circulating in the refrigerant circulation system 21 is a mixed refrigerant, specifically a non-azeotropic mixed refrigerant, which is a mixture of a low-boiling-point refrigerant 11 (a first refrigerant with a first boiling point) and a high-boiling-point refrigerant 12 (a second refrigerant with a second boiling point higher than the first boiling point), similar to the first embodiment. However, unlike in the first embodiment, the high-boiling-point refrigerant 12 is in a gaseous state when it is fed into the compressor 22.

[0039] The compressor 22 compresses the gaseous refrigerant (gaseous refrigerant 13) and sends it to the condenser 23. The condenser 23 condenses the gaseous refrigerant 13 sent from the compressor 22 into a liquid refrigerant (liquid refrigerant 14) by using a cooling medium (not shown), such as cooling water, to remove heat. The liquid refrigerant 14 from the condenser 23 is reduced in pressure to near the saturated vapor pressure by the expansion valve 24 and sent to the heat exchange container 25. In this way, the expansion valve 24 functions as a pressure reducer that reduces the pressure of the liquid refrigerant 14 from the condenser 23 and supplies it to the heat exchange container 25.

[0040] The heat exchange container 25 includes a heat exchange region 252 that exchanges heat with the object to be cooled 80, and the object to be cooled 80 is housed within the heat exchange region 252. When the object to be cooled 80 housed within the heat exchange container 25 generates heat, the low-boiling-point refrigerant 11 of the liquid refrigerant 14 (mixed refrigerant) supplied to the heat exchange container 25 boils and cools the object to be cooled 80 with its latent heat of vaporization, while the high-boiling-point refrigerant 12 cools the object to be cooled 80 by convection. In this way, the low-boiling-point refrigerant 11 boils and cools the object to be cooled 80 in the heat exchange region 252 within the heat exchange container, becoming a gaseous state, while the high-boiling-point refrigerant 12 cools the object to be cooled 80 by convection in a liquid state within the heat exchange region 252 within the heat exchange container. The low-boiling-point refrigerant 11 that passes through the heat exchange region 252 within the heat exchange container and is discharged from the heat exchange container 25 becomes either a liquid state or a gas-liquid mixed-phase (two-phase) state, depending on the heat generation state of the object to be cooled 80. On the other hand, the high-boiling-point refrigerant 12 that passes through the heat exchange region 252 in the heat exchange container and is discharged from the heat exchange container 25 always maintains a liquid phase state regardless of the exothermic state of the object to be cooled 80. A pressure sensor 26 is provided downstream of the expansion valve 24, and the opening degree of the expansion valve 24 is controlled so that the pressure in the heat exchange container 25 (the pressure detected by the pressure sensor 26) is always near the vapor pressure of the low-boiling-point refrigerant 11.

[0041] The refrigerant discharged from the heat exchange container 25 always contains liquid refrigerant 14. Therefore, if the refrigerant discharged from the heat exchange container 25 is returned directly to the compressor 22, the compressor 22 will be damaged because it cannot compress the refrigerant in its liquid phase.

[0042] Therefore, in this embodiment, a gas-liquid separation unit 27 is provided between the heat exchange container 25 and the compressor 22 to separate the gas-liquid mixed refrigerant (mixed refrigerant) discharged from the heat exchange container 25 into a gaseous refrigerant 13 (refrigerant in gaseous phase) and a liquid refrigerant 14 (refrigerant in liquid phase). The refrigerant circulation system 21 also includes a first path 211 for returning the liquid refrigerant 14 separated by the gas-liquid separation unit 27 to the compressor 22, and a second path 212 for returning the gaseous refrigerant 13 separated by the gas-liquid separation unit 27 to the compressor 22. The first path 211 is connected to the compressor 22 via a first vaporization unit 28 that vaporizes the liquid refrigerant 14 separated by the gas-liquid separation unit 27 into a gaseous refrigerant. On the other hand, the second path 212 is directly connected to the compressor 22.

[0043] Thus, in this embodiment, the gaseous refrigerant 13 separated in the gas-liquid separation unit 27 is returned directly to the compressor 22 via the second path 212, while the liquid refrigerant 14 separated in the gas-liquid separation unit 27 is sent to the first vaporization unit 28 before being returned to the compressor 22. The first vaporization unit 28 branches off the high-temperature gaseous refrigerant 15 downstream of the compressor 22 before returning it to the condenser 23, where it merges it with the liquid refrigerant 14 separated in the gas-liquid separation unit 27, and the liquid refrigerant 14 is evaporated by the high-temperature gaseous refrigerant 15 before being returned to the compressor 22.

[0044] Furthermore, the first vaporization unit 28 includes a flow sensor 29 for detecting the flow rate of the liquid refrigerant 14, a throttle valve 30 for adjusting the flow rate of the high-temperature gaseous refrigerant 15, and a flow control unit 31. Based on the flow rate of the liquid refrigerant 14 detected by the flow sensor 29, the flow control unit 31 controls the throttle valve 30 so that the flow rate of the high-temperature gaseous refrigerant 15 to be mixed with the liquid refrigerant 14 is the flow rate necessary to evaporate (vaporize) the liquid refrigerant 14. In this way, the first vaporization unit 28 vaporizes the liquid refrigerant 14 by mixing a portion of the gaseous refrigerant 15 (mixed refrigerant in gaseous state) sent from the compressor 22 with the liquid refrigerant 14 separated in the gas-liquid separation unit 27 via the throttle valve 30. An ultrasonic sensor is preferred as the flow sensor 29, but it is not limited to this.

[0045] Here, an increase in the flow rate of liquid refrigerant 14 contained in the refrigerant discharged from the heat exchange container 25 means that the amount of heat generated by the object to be cooled 80 built into the heat exchange container 25 is decreasing, so the flow rate of liquid refrigerant 14 supplied to the heat exchange container 25 can be reduced. Therefore, the flow control unit 31 controls (throttles) the opening degree of the expansion valve 24 and controls the opening degree of the throttle valve 30 to properly control the flow rate balance between the liquid refrigerant 14 separated in the gas-liquid separation unit 27 and the high-temperature gaseous refrigerant 15 from the compressor 22. Furthermore, the flow control unit 31 may control the compression capacity (total flow rate of refrigerant) of the compressor 22 via the inverter 32. This prevents the liquid refrigerant 14 from returning to the compressor 22 and allows the refrigeration cycle to be maintained in response to heat load fluctuations.

[0046] Thus, according to this embodiment, a cooling device CA2 that can be applied to a general refrigeration cycle can be realized. In the cooling device CA1 of the first embodiment, when a large amount of heat is recovered in the heat exchange container 7 and the heat is discharged in the condenser 2, two circulation systems via separate refrigeration cycles are required. On the other hand, in the cooling device CA2 of this embodiment, heat can be discharged with a single circulation system. Therefore, a cooling device CA2 that contributes to space saving and energy saving can be provided.

[0047] <Third Embodiment> Figure 5 shows the configuration of the cooling device CA3 in the third embodiment of the present invention. The cooling device CA3 in this embodiment is an improvement over the cooling device CA2 in the second embodiment. Matters not mentioned in this embodiment are the same as in the second embodiment.

[0048] In this embodiment, a second vaporization unit 33 is newly provided between the heat exchange container 25 and the gas-liquid separation unit 27 for vaporizing the gas-liquid mixed refrigerant (mixed refrigerant) discharged from the heat exchange container 25. The second vaporization unit 33 is, for example, provided inside the condenser 23 and is realized as a heat exchanger that performs heat exchange between the high-temperature gaseous refrigerant 15 (mixed refrigerant in gaseous state) sent from the compressor 22 and the gas-liquid mixed refrigerant (mixed refrigerant) discharged from the heat exchange container 25. In the second vaporization unit 33, the liquid refrigerant 14 contained in the refrigerant discharged from the heat exchange container 25 is heated by the high-temperature gaseous refrigerant 15 and partially evaporates. On the other hand, the high-temperature gaseous refrigerant 15 is cooled by the latent heat of the evaporated liquid refrigerant 14 and partially condenses.

[0049] According to this embodiment, in the condenser 23, a portion of the high-temperature gaseous refrigerant 15 sent from the compressor 22 is condensed with the liquid refrigerant 14 discharged from the heat exchange container 25, thereby reducing the amount of heat discharged outside the system. Furthermore, by providing two vaporization sections, a first vaporization section 28 and a second vaporization section 33, the risk of damage to the compressor 22 due to the mixing of liquid refrigerant 14 can be further reduced.

[0050] <Fourth Embodiment> Figures 6A, 6B, and 6C are schematic diagrams showing the configuration of the cooling device in the fourth embodiment of the present invention. While the first to third embodiments are limited to the cooling of an object 80 built into the heat exchange container 7 or 25, in large-scale systems such as exposure equipment, there are many objects to be cooled (heat-generating elements) in addition to the object 80. Furthermore, the refrigerant that did not evaporate in the heat exchange container 7 or 25 and the liquid refrigerant 14 separated in the gas-liquid separation unit 27 are in a liquid phase state and therefore have the ability to boil-cool the object to be cooled. Therefore, in this embodiment, a new path is configured to cool another object to be cooled (an object different from the object 80 to be cooled) that is not built into the heat exchange container 7 or 25.

[0051] Figure 6A shows a case in the first embodiment where the cooling device CA1 is configured to cool an object 81 different from the object to be cooled 80. The cooling device CA1 has a heat exchanger 34 downstream of the heat exchange container 7. The heat exchanger 34 comes into thermal contact with the object to be cooled 81 and cools the object to be cooled 81 by exchanging heat between the gas-liquid mixed refrigerant (mixed refrigerant) discharged from the heat exchange container 7 and the object to be cooled 81. In the heat exchanger 34, the liquid refrigerant 14 that has not evaporated in the heat exchange container 7 absorbs heat from the object to be cooled 81 and boils, thereby boiling-cooling the object to be cooled 81. The refrigerant that has passed through the heat exchanger 34 is returned to the condenser 2 in a gas-liquid mixed state, cooled in the condenser 2, undergoes a phase change, and is recirculated as liquid refrigerant 14.

[0052] Figure 6B shows a case in the second embodiment where the cooling device CA2 is configured to cool an object 81 different from the object to be cooled 80. The cooling device CA2 has a heat exchanger 34 in the first path 211 through which the liquid refrigerant 14 separated in the gas-liquid separation section 27 downstream of the heat exchange container 25 flows. The heat exchanger 34 comes into thermal contact with the object to be cooled 81 and cools the object to be cooled 81 by exchanging heat between the liquid refrigerant 14 separated in the gas-liquid separation section 27 and the object to be cooled 81. In the heat exchanger 34, the liquid refrigerant 14 separated in the gas-liquid separation section 27 absorbs heat from the object to be cooled 81 and boils, thereby boiling-cooling the object to be cooled 81. The refrigerant that has passed through the heat exchanger 34 is sent to the first vaporization section 28 in a gas phase state or a gas-liquid mixed phase state, where it is completely vaporized and returned to the compressor 22 as gaseous refrigerant 13 for recirculation.

[0053] Figure 6C shows a case in the third embodiment where the cooling device CA3 is configured to cool an object 81 different from the object 80 to be cooled. In the cooling device CA3, the first path 211 through which the liquid refrigerant 14 separated in the gas-liquid separation unit 27 flows is branched into a third path 213 and a fourth path 214. The third path 213 is a path that leads to the second vaporization unit 33 via the expansion valve 35 and the heat exchanger 34, and the fourth path 214 is a path that leads to the second vaporization unit 33 via the throttle valve 36. In such a system, the pressure of the liquid refrigerant 14 is adjusted via the expansion valve 35 so that it becomes a predetermined vapor pressure. This is equivalent to adjusting the boiling point of the liquid refrigerant 14, making it possible to cool the object 81 to be cooled at a predetermined temperature. Therefore, it is particularly suitable when the object 81 to be cooled requires temperature control. It should be noted that a similar configuration can also be applied to the cooling device CA1 in the first embodiment and the cooling device CA2 in the second embodiment.

[0054] According to this embodiment, a cooling target 81 different from the cooling target 80 built into the heat exchange container 7 or 25 can be boiled and cooled with a high-boiling-point refrigerant 12. Therefore, the cooling device in this embodiment is equivalent to a general refrigeration cycle and can efficiently cool an entire large system such as an exposure apparatus with a single refrigerant circulation system.

[0055] <Fifth Embodiment> Hereinafter, with reference to Figures 7, 8, and 9, a semiconductor manufacturing apparatus to which cooling devices CA1, CA2, and CA3 can be applied will be described as an example, and in this embodiment, a semiconductor manufacturing apparatus to which cooling device CA1 is applied will be described.

[0056] Figure 7 is a schematic diagram showing the configuration of an exposure apparatus 100 as an example of a semiconductor manufacturing apparatus, and more specifically, a pattern forming apparatus. The exposure apparatus 100 is configured to transfer the pattern of a master plate 101 to a photosensitive material layer supplied (coated) to a substrate 102 via a projection optical system 140. The exposure apparatus 100 includes an illumination optical system 150 for illuminating the master plate 101, a projection optical system 140, a substrate positioning mechanism SPM for positioning the substrate 102, and a master plate positioning mechanism (not shown) for positioning the master plate 101.

[0057] The substrate positioning mechanism SPM includes a substrate stage 110 that supports a substrate chuck for holding a substrate 102, a drive mechanism 120 that drives the substrate stage 110, and a base member 130 that supports the drive mechanism 120. The drive mechanism 120 includes an actuator comprising a movable element 122 that moves together with the substrate stage 110 and a stator 124 fixed to the base member 130. The stator 124 includes coils (coil arrays) as objects to be cooled 80 by the cooling device CA1. The cooling device CA1 is configured to cool the coils of the stator 124 as objects to be cooled 80.

[0058] Figure 8 is a schematic diagram showing the configuration of an imprint apparatus 200 as an example of a semiconductor manufacturing apparatus, and more specifically, a pattern forming apparatus. The imprint apparatus 200 is configured to transfer the pattern of a master plate 101 (template) onto an imprint material placed (supplied) on a substrate 102. The imprint apparatus 200 includes a master plate driving mechanism 160 for driving the master plate 101, a substrate positioning mechanism SPM for positioning the substrate 102, and a curing unit 170 for curing the imprint material placed on the substrate 102.

[0059] At least one of the master plate drive mechanism 160 and the substrate positioning mechanism SPM can align the pattern area of ​​the master plate 101 with the shot area of ​​the substrate 102. Furthermore, at least one of the master plate drive mechanism 160 and the substrate positioning mechanism SPM can contact the pattern area of ​​the master plate 101 with the imprint material placed on the substrate 102 and separate the pattern area of ​​the master plate 101 from the imprint material placed on the substrate 102.

[0060] In the imprint apparatus 200, the imprint material placed on the substrate 102 is brought into contact with the pattern area of ​​the master plate 101, and the imprint material is cured by the curing unit 170, separating the cured imprint material from the master plate 101. As a result, a pattern consisting of the cured imprint material is formed on the substrate 102. In other words, the pattern of the master plate 101 is transferred to the imprint material placed on the substrate 102.

[0061] As described above, the substrate positioning mechanism SPM includes a substrate stage 110 that supports a substrate chuck for holding the substrate 102, a drive mechanism 120 that drives the substrate stage 110, and a base member 130 that supports the drive mechanism 120. The drive mechanism 120 includes an actuator composed of a movable element 122 that moves together with the substrate stage 110 and a stator 124 fixed to the base member 130. The stator 124 includes coils (coil arrays) as objects to be cooled 80 by the cooling device CA1. The cooling device CA1 is configured to cool the coils of the stator 124 as objects to be cooled 80.

[0062] Figure 9 is a schematic diagram showing the configuration of a plasma processing apparatus 300 as an example of semiconductor manufacturing equipment. The plasma processing apparatus 300 includes, for example, a CVD apparatus, an etching apparatus, a sputtering apparatus, etc. The plasma processing apparatus 300 has a chamber 330 and an electrode structure as one or more objects to be cooled 80a and 80b arranged inside the chamber 330.

[0063] In this embodiment, the substrate 302 is supported by the object to be cooled 80a. A gas for generating plasma is supplied to the inside of the chamber 330. When the plasma processing apparatus 300 is configured as a CVD apparatus, a gas for film formation is supplied to the inside of the chamber 330. When the plasma processing apparatus 300 is configured as an etching apparatus, an etching gas is supplied to the inside of the chamber 330. When the plasma processing apparatus 300 is configured as a sputtering apparatus, a gas for generating plasma is supplied to the inside of the chamber 330, and a target is attached to the electrode structure as the object to be cooled 80b. The cooling device CA1 is configured to cool the objects to be cooled 80a and 80b.

[0064] <Sixth Embodiment> One aspect of the present invention is a semiconductor manufacturing method comprising the steps of processing a substrate with semiconductor manufacturing equipment, such as the exposure apparatus 100, imprint apparatus 200, and plasma processing apparatus 300 described above, and processing the substrate processed in the above step. The step of processing the substrate with semiconductor manufacturing equipment includes, for example, the steps of forming a pattern on the substrate, forming a film on the substrate, and etching the substrate or a film formed on the substrate. The step of processing the substrate includes, for example, the steps of dividing (dicing) the substrate and sealing the substrate. The semiconductor manufacturing method in this embodiment is advantageous compared to conventional methods in at least one of the performance, quality, productivity, and production cost of the semiconductor.

[0065] The disclosures herein include the following cooling devices, semiconductor manufacturing equipment, and semiconductor manufacturing methods.

[0066] (Item 1) A cooling device for cooling an object to be cooled, It has a circulation system for circulating a refrigerant to cool the object to be cooled, The circulation system is provided with a container that includes a region where heat exchange takes place between at least a portion of the object to be cooled and the refrigerant. The refrigerant is a mixed refrigerant obtained by mixing a first refrigerant with a first boiling point and a second refrigerant with a second boiling point higher than the first boiling point. The circulation system circulates the mixed refrigerant such that the entire region is exposed to a mixed refrigerant in which both the first and second refrigerants are in the liquid phase, and a mixed refrigerant in a gas-liquid mixed phase is discharged from the container. A cooling device characterized by the following features.

[0067] (Item 2) The cooling device according to item 1, characterized in that the first refrigerant boils and cools the object to be cooled in the region to a gaseous state, and the second refrigerant is mixed with the first refrigerant in a mixing ratio such that it convectually cools the object to be cooled in the region in a liquid state and compresses the first refrigerant in a gaseous state.

[0068] (Item 3) The cooling device according to item 1 or 2, characterized in that the mixed refrigerant is a non-azeotropic mixed refrigerant.

[0069] (Item 4) The circulation system includes a compressor that compresses and delivers a gaseous mixed refrigerant; a condenser that condenses the gaseous mixed refrigerant delivered from the compressor into a liquid mixed refrigerant; a pressure reducer that reduces the pressure of the liquid mixed refrigerant from the condenser and supplies it to the container; and a gas-liquid separation unit that separates the gaseous mixed refrigerant discharged from the container into a gaseous refrigerant and a liquid refrigerant. The circulation system includes a first path for returning the liquid-phase refrigerant separated in the gas-liquid separation unit to the compressor, and a second path for returning the gaseous-phase refrigerant separated in the gas-liquid separation unit to the compressor. The first path is connected to the compressor via a first vaporization unit that vaporizes the liquid-phase refrigerant separated in the gas-liquid separation unit into a gaseous refrigerant. The second path is directly connected to the compressor. A cooling device according to any one of items 1 to 3, characterized by the above.

[0070] (Item 5) The cooling device according to item 4, characterized in that the first vaporization unit vaporizes the liquid phase refrigerant by combining a portion of the mixed refrigerant in the gas phase state delivered from the compressor with the liquid phase refrigerant separated in the gas-liquid separation unit via a throttle valve.

[0071] (Item 6) The cooling device according to item 4 or 5, further comprising a second vaporization unit provided between the container and the gas-liquid separation unit for vaporizing the gas-liquid mixed refrigerant discharged from the container.

[0072] (Item 7) The cooling apparatus according to item 6, characterized in that the second vaporization section includes a heat exchanger provided inside the condenser, which performs heat exchange between the mixed refrigerant in a gaseous state delivered from the compressor and the mixed refrigerant in a gas-liquid mixed state discharged from the container.

[0073] (Item 8) The cooling device according to any one of items 4 to 7, further comprising a heat exchanger that cools a different object to be cooled by performing heat exchange between the refrigerant in a liquid phase state separated in the gas-liquid separation unit and an object to be cooled that is different from the object to be cooled.

[0074] (Item 9) The cooling device according to any one of items 1 to 3, characterized in that the circulation system includes a condenser that condenses the mixed refrigerant in a gas-liquid mixed phase state discharged from the container into a mixed refrigerant in a liquid phase state, a pump that delivers the mixed refrigerant in a liquid phase state from the condenser, and a pressure reducer that reduces the pressure of the mixed refrigerant in a liquid phase state delivered from the pump and supplies it to the container.

[0075] (Item 10) The cooling device according to item 9, further comprising a heat exchanger that cools a different object to be cooled by performing heat exchange between a gas-liquid mixed refrigerant discharged from the container and an object to be cooled that is different from the object to be cooled.

[0076] (Item 11) The cooling device according to any one of items 1 to 10, characterized in that the first refrigerant is R-1234zeE or R-1234yf.

[0077] (Item 12) A semiconductor manufacturing apparatus having a heat-generating section, Having a cooling device described in any one of items 1 to 11, The cooling device is configured to cool the heat-generating part as the object to be cooled. A semiconductor manufacturing apparatus characterized by the following features.

[0078] (Item 13) It is configured as a pattern forming device for forming patterns. A semiconductor manufacturing apparatus as described in item 12, characterized by the features described herein.

[0079] (Item 14) A step of processing a substrate using semiconductor manufacturing equipment described in item 12 or 13, A process for processing the substrate processed in the above process, A semiconductor manufacturing method characterized by having the following features.

[0080] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of Symbols]

[0081] CA1, CA2, CA3: Cooling device 1: Refrigerant circulation system 7: Heat exchange vessel 10: Refrigerant 11: Low boiling point refrigerant 12: High boiling point refrigerant 13: Gaseous refrigerant 14: Liquid refrigerant 80: Object to be cooled

Claims

1. A cooling device for cooling an object to be cooled, a circulation system that circulates a refrigerant for cooling the object to be cooled, the circulation system is provided with a container including a region where heat exchange occurs between at least a portion of the object to be cooled and the refrigerant, The refrigerant is a mixed refrigerant obtained by mixing a first refrigerant having a first boiling point and a second refrigerant having a second boiling point higher than the first boiling point, the circulation system circulates the mixed refrigerant such that the mixed refrigerant enters the vessel at a predetermined temperature; The first refrigerant has a vapor pressure higher than the withstand pressure of the container at the predetermined temperature. A cooling device characterized by:

2. The cooling device described in claim 1, characterized in that the circulation system circulates the mixed refrigerant so that the area is exposed to the mixed refrigerant in which the first refrigerant and the second refrigerant have entered the container in a liquid phase, and the mixed refrigerant comprising at least a portion of the first refrigerant in a gas phase state and the second refrigerant in a liquid phase is discharged from the container.

3. 2. The cooling device according to claim 1, wherein the first refrigerant boils and cools the object to be cooled in the region to a gas phase, and the second refrigerant is mixed with the first refrigerant in a mixture ratio such that the first refrigerant boils and cools the object to be cooled in the region to a gas phase, and the second refrigerant is liquid in the region to convectively cool the object to be cooled and compresses the first refrigerant in the gas phase.

4. 2. The cooling device according to claim 1, wherein the mixed refrigerant is a non-azeotropic mixed refrigerant.

5. The circulation system includes a compressor that compresses and delivers a gas-phase mixed refrigerant, a condenser that condenses the gas-phase mixed refrigerant delivered from the compressor to a liquid-phase mixed refrigerant, a pressure reducer that reduces the pressure of the liquid-phase mixed refrigerant from the condenser and supplies it to the container, and a gas-liquid separation unit that separates the gas-liquid mixed phase mixed refrigerant discharged from the container into a gas-phase refrigerant and a liquid-phase refrigerant, The circulation system includes a first path for returning the liquid phase refrigerant separated in the gas-liquid separation unit to the compressor, and a second path for returning the gas phase refrigerant separated in the gas-liquid separation unit to the compressor, The first path is connected to the compressor via a first vaporization unit that vaporizes the liquid-phase refrigerant separated by the gas-liquid separation unit to convert it into a gas-phase refrigerant, The second path is directly connected to the compressor.

2. The cooling device according to claim 1 .

6. 6. The cooling device according to claim 5, wherein the first vaporization unit vaporizes the liquid phase refrigerant by merging a portion of the mixed refrigerant in a gas phase state discharged from the compressor with the liquid phase refrigerant separated in the gas-liquid separation unit via a throttling valve.

7. 6. The cooling device according to claim 5, further comprising a second vaporization section provided between the container and the gas-liquid separation section for vaporizing the mixed refrigerant in a gas-liquid mixed phase state discharged from the container.

8. The cooling device according to claim 7, characterized in that the second evaporation section includes a heat exchanger provided inside the condenser and performing heat exchange between the mixed refrigerant in a gas phase state discharged from the compressor and the mixed refrigerant in a gas-liquid mixed phase state discharged from the container.

9. 6. The cooling device according to claim 5, further comprising a heat exchanger that cools the different object to be cooled by performing heat exchange between the liquid phase refrigerant separated by the gas-liquid separation section and the different object to be cooled.

10. A cooling device as described in claim 1, characterized in that the circulation system is provided with a heater that heats the mixed refrigerant so that the mixed refrigerant reaches the predetermined temperature.

11. 2. The cooling device according to claim 1, wherein the circulation system is provided with a condenser that condenses the mixed refrigerant in a gas-liquid mixed phase state discharged from the container to a mixed refrigerant in a liquid phase state, a pump that delivers the mixed refrigerant in the liquid phase state from the condenser, and a pressure reducer that reduces the pressure of the mixed refrigerant in the liquid phase delivered from the pump and supplies it to the container.

12. 12. The cooling device according to claim 11, further comprising a heat exchanger that performs heat exchange between the mixed refrigerant in a gas-liquid mixed phase state discharged from the container and a cooling object other than the cooling object, thereby cooling the cooling object.

13. 2. The cooling device of claim 1, wherein the first refrigerant is R-1234zeE or R-1234yf.

14. A semiconductor manufacturing apparatus having a heat generating portion, A cooling device according to any one of claims 1 to 13, The cooling device is configured to cool the heat generating portion as a cooling object. A semiconductor manufacturing apparatus comprising:

15. A pattern forming apparatus configured to form a pattern, 15. The semiconductor manufacturing apparatus according to claim 14.

16. Processing a substrate by the semiconductor manufacturing apparatus according to claim 14; a step of processing the substrate treated in the above step; A semiconductor manufacturing method comprising the steps of:

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