Regeneration method of cryopump and cryo system

Abstract

To provide a regeneration method of a cryopump which can inhibit deviation of a temperature on a surface of a pump case from a dew point, and to provide a cryo system.SOLUTION: A regeneration method of a cryopump 10 includes: heating the inside of a pump case 12 with a heating part 13 configured to heat the inside of the pump case 12 included in the cryopump 10; and introducing a purge gas into the pump case 12 after the heating part 13 starts heating the inside of the pump case 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a method for regenerating a cryopump and a cryosystem. [Background technology]

[0002] The cryopump includes a pump case, a refrigerator, a heat shield, and a cryopanel. The refrigerator includes a first stage cooled to a first temperature and a second stage cooled to a second temperature lower than the first temperature. The heat shield is connected to the first stage, thereby being cooled to the first temperature. The cryopanel is located within the heat shield and connected to the second stage, thereby being cooled to the second temperature. The pump case houses the first and second stages of the refrigerator, the heat shield, and the cryopanel. In the cryopump, the cryopanel, cooled to an extremely low temperature, condenses the gas in the vacuum chamber, thereby evacuating the gas from the vacuum chamber (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-092331 Summary of the Invention [Problem to be solved by the invention]

[0004] Cryopumps store condensed gas in cryopanels. For this reason, cryopumps require a regeneration process, which is a process for releasing the gas stored in the cryopanels. In the regeneration process, the introduction of purge gas into the pump case is started at the same time as the temperature of the cryopump is increased, in order to increase the rate of temperature increase. The introduction of purge gas increases the rate of temperature increase in the pump case, while causing a decrease in the temperature on the surface of the pump case. As a result, the temperature on the surface of the pump case falls below the dew point of the environment in which the cryopump is installed, causing condensation on the surface of the pump case. [Means for solving the problem]

[0005] A method for regenerating a cryopump to solve the above problems includes heating the inside of a pump case provided in a cryopump using a heating unit configured to heat the inside of the pump case, and introducing a purge gas into the pump case after heating of the inside of the pump case by the heating unit begins.

[0006] A cryosystem for solving the above problems includes a cryopump including a refrigerator, a pump case that houses the refrigerator, a heating unit configured to be able to heat the inside of the pump case, and a purge gas introduction unit connected to the pump case, and a control unit that controls the operation of the heating unit and the purge gas introduction unit. The control unit is configured to be able to control the operation of the heating unit and the purge gas introduction unit so as to introduce a purge gas into the pump case after the heating unit starts heating the inside of the pump case.

[0007] According to the above-mentioned cryopump regeneration method and cryosystem, the purge gas is introduced into the pump case heated by the heating unit, so that the temperature of the surface of the pump case is less likely to decrease due to the introduction of the purge gas, and therefore the deviation of the temperature of the surface of the pump case from the dew point is suppressed, thereby suppressing condensation on the surface of the pump case.

[0008] In the above-mentioned method for regenerating a cryopump, heating the inside of the pump case may include stopping heating of the inside of the pump case by the heating unit after starting to introduce the purge gas into the pump case.

[0009] According to the above-described method for regenerating a cryopump, since the method includes a period during which both the introduction of purge gas into the pump case and the heating of the inside of the pump case by the heating unit are performed, the temperature inside the pump case is likely to increase.

[0010] In the above-mentioned method for regenerating a cryopump, heating the inside of the pump case may include heating the inside of the pump case by heating a first stage and a second stage provided in a refrigerator of the cryopump.

[0011] According to the above-described method for regenerating a cryopump, since both the first stage and the second stage are heated, the temperature inside the pump case is more likely to increase than when only one of the two stages is heated.

[0012] In the above-described method for regenerating a cryopump, heating the inside of the pump case may include heating the inside of the pump case using a motor provided in the refrigerator. According to the above-mentioned method for regenerating a cryopump, the motor of the refrigerator also serves as the heating unit for heating the cryopump, so that the cryopump does not need to be equipped with a separate heating unit, thereby simplifying the structure of the cryopump.

[0013] In the above-mentioned cryopump regeneration method, heating the inside of the pump case may include a first period during which the heating section heats the inside of the pump case before introducing the purge gas, which is longer than a second period during which the purge gas is introduced.

[0014] According to the above-mentioned method for regenerating a cryopump, since the first period is longer than the second period, purge gas is introduced into a pump case that is sufficiently heated by the heating section, and therefore the introduction of purge gas makes it difficult for the temperature on the surface of the pump case to decrease further. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a system configuration diagram showing the configuration of a cryosystem. [Diagram 2] FIG. 2 is a timing chart showing the timing of switching on and off in the heating unit and the timing of switching on and off in the purge gas introduction unit in one embodiment. [Diagram 3] FIG. 3 is a timing chart showing changes in temperature of the first stage, the second stage, and the surface temperature of the pump case in this embodiment. [Figure 4] FIG. 4 is a timing chart showing the timing of switching on and off in the heating part and the timing of switching on and off in the purge gas introduction part in the reference example. [Diagram 5] FIG. 5 is a timing chart showing the transition of the temperature of the first stage, the temperature of the second stage, and the temperature on the surface of the pump case in the same reference example. [Figure 6] FIG. 6 is a graph showing the transition of temperature at each part of the cryopump in the test example. [Figure 7] FIG. 7 is a table showing the minimum temperatures at each part of the cryopump in the test example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] 1 to 7, an embodiment of a method for regenerating a cryopump and a cryopump will be described. [Cryosystem] The cryosystem will be described with reference to FIG.

[0017] As shown in Fig. 1, the cryosystem 1 includes a cryopump 10 and a control unit 20. The cryopump 10 includes a refrigerator 11, a pump case 12, a heating unit 13, and a purge gas introduction unit 14. The pump case 12 houses the refrigerator 11. The heating unit 13 is configured to be able to heat the inside of the pump case 12. The purge gas introduction unit 14 is connected to the pump case 12.

[0018] The control unit 20 controls the driving of the heating unit 13 and the driving of the purge gas introduction unit 14. The control unit 20 is configured to be capable of controlling the driving of the heating unit 13 and the driving of the purge gas introduction unit 14 so as to introduce a purge gas into the pump case 12 after the heating of the inside of the pump case 12 by the heating unit 13 starts.

[0019] According to the cryosystem 1 of the present disclosure, the purge gas is introduced into the pump case 12 heated by the heating unit 13, so that the introduction of the purge gas is less likely to lower the temperature on the surface of the pump case 12. Therefore, the deviation of the temperature on the surface of the pump case 12 from the dew point is suppressed, and condensation on the surface of the pump case 12 is suppressed.

[0020] The refrigerator 11 of the cryopump 10 is, for example, a Gifford-McMahon (GM) refrigerator. The refrigerator 11 includes a first stage 11A and a second stage 11B. During the operation of the refrigerator 11, the temperature of the second stage 11B is lower than the temperature of the first stage 11A. The temperature of the first stage 11A may be, for example, 50 K or more and 110 K or less. The temperature of the second stage 11B may be, for example, 10 K or more and 20 K or less. The refrigerator 11 includes a first cylinder 11C and a second cylinder 11D. The first cylinder 11C is connected to the first stage 11A. The second cylinder 11D is connected to the first stage 11A and the second stage 11B.

[0021] The refrigerator 11 includes a motor 11M. As the motor 11M rotates, adiabatic expansion occurs in an expansion chamber of the refrigerator 11, thereby cooling the first stage 11A and the second stage 11B of the refrigerator 11. As an extended application of this embodiment, the refrigerator 11 may be configured to heat the first stage 11A and the second stage 11B by rotating in a direction opposite to the direction in which the motor cools the stages 11A and 11B.

[0022] The pump case 12 includes a first cylindrical portion 12A and a second cylindrical portion 12B connected to the first cylindrical portion 12A. The first cylindrical portion 12A houses a first cylinder 11C and a first stage 11A. The second cylindrical portion 12B houses a second cylinder 11D and a second stage 11B.

[0023] The pump case 12 has a first port 12P1 and a second port 12P2. The first port 12P1 is located in the first cylindrical portion 12A. The second port 12P2 is located in the second cylindrical portion 12B. The first port 12P1 is connected to a purge gas discharge portion 17. The second port 12P2 is connected to a purge gas introduction portion 14.

[0024] The purge gas introduction part 14 is a valve for introducing the purge gas into the pump case 12. The purge gas introduction part 14 is, for example, an electromagnetic valve. When the purge gas introduction part 14 is in an on state, the purge gas introduction part 14 has an open state, and the purge gas is introduced into the pump case 12 through the second port 12P2. When the purge gas introduction part 14 is in an off state, the purge gas introduction part 14 has a closed state, and the introduction of the purge gas through the second port 12P2 is stopped. A gas cylinder GC that stores the purge gas is connected to the purge gas introduction part 14. Nitrogen gas, which is an example of the purge gas, is stored in the gas cylinder GC.

[0025] The cryopump 10 includes a heat shield 15 located in the second cylindrical portion 12B of the pump case 12. The heat shield 15 is connected to the first stage 11A. During the operation of the refrigerator 11, the temperature of the heat shield 15 is approximately equal to the temperature of the first stage 11A. The refrigerator 11 includes a plurality of cryopanels 16 located in the heat shield 15. Each cryopanel 16 is connected to the second stage 11B. During the operation of the refrigerator 11, the temperature of each cryopanel 16 is approximately equal to the temperature of the second stage 11B.

[0026] The purge gas exhaust section 17 is a valve for exhausting the purge gas to the outside of the pump case 12. The purge gas exhaust section 17 is, for example, an electromagnetic valve. When the purge gas exhaust section 17 is in an on state, the purge gas exhaust section 17 has an open state, and the purge gas is exhausted to the outside of the pump case 12 via the first port 12P1. When the purge gas exhaust section 17 is in an off state, the purge gas exhaust section 17 has a closed state, and the exhaust of the purge gas via the first port 12P1 is stopped. The purge gas exhaust section 17 is connected to an exhaust duct ED.

[0027] The heating unit 13 may be configured to be capable of heating both the first stage 11A and the second stage 11B. The heating unit 13 may be configured to be capable of heating only the first stage 11A, or may be configured to be capable of heating only the second stage 11B. The heating unit 13 is located within the space defined by the pump case 12 and is not in contact with the pump case 12. The heating unit 13 may be, for example, a heater.

[0028] The cryosystem 1 includes a first temperature sensor 21 and a second temperature sensor 22. The first temperature sensor 21 detects the temperature of the first stage 11A. The second temperature sensor 22 detects the temperature of the second stage 11B. Each of the temperature sensors 21, 22 may be, for example, a thermocouple.

[0029] The control unit 20 is electrically connected to the heating unit 13, the purge gas introduction unit 14, the purge gas exhaust unit 17, the first temperature sensor 21, and the second temperature sensor 22. The control unit 20 stores conditions related to the regeneration process of the cryopump 10. The control unit 20 controls the driving of the heating unit 13, the purge gas introduction unit 14, and the purge gas exhaust unit 17. The control unit 20 controls the driving of the heating unit 13, the purge gas introduction unit 14, and the purge gas exhaust unit 17 based on the conditions of the regeneration process stored in the control unit 20, for example.

[0030] The control unit 20 receives an input of the temperature of the first stage 11A detected by the first temperature sensor 21 from the first temperature sensor 21. The control unit 20 receives an input of the temperature of the second stage 11B detected by the second temperature sensor 22 from the second temperature sensor 22.

[0031] The control unit 20 may change the state of the purge gas introduction unit 14 from OFF to ON after a predetermined heating period has elapsed from the time when the heating unit 13 starts heating the inside of the pump case 12. In this case, the control unit 20 stores the heating period as one of the conditions for the regeneration process.

[0032] Alternatively, the control unit 20 may change the state of the purge gas introduction unit 14 from off to on based on at least one of the first temperature of the first stage 11A detected by the first temperature sensor 21 and the second temperature of the second stage 11B detected by the second temperature sensor 22.

[0033] For example, when the control unit 20 changes the state of the purge gas introduction unit 14 based only on the first temperature, the control unit 20 may change the state of the purge gas introduction unit 14 from off to on, provided that the first temperature is equal to or higher than the first set temperature. In this case, the control unit 20 stores the first set temperature as one of the conditions for the regeneration process. Alternatively, when the control unit 20 changes the state of the purge gas introduction unit 14 based only on the second temperature, the control unit 20 may change the state of the purge gas introduction unit 14 from off to on, provided that the second temperature is equal to or higher than the second set temperature. In this case, the control unit 20 stores the second set temperature as one of the conditions for the regeneration process.

[0034] Alternatively, the control unit 20 may change the state of the purge gas introduction unit 14 based on both the first temperature and the second temperature. In this case, the control unit 20 changes the state of the purge gas introduction unit 14 from OFF to ON under the condition that the first temperature is equal to or higher than the first set temperature and the second temperature is equal to or higher than the second set temperature. The control unit 20 stores the first set temperature and the second set temperature as conditions for the regeneration process.

[0035] The control unit 20 may change the state of the purge gas introduction unit 14 from ON to OFF after a predetermined purge gas introduction period has elapsed from the point in time when the introduction of the purge gas by the purge gas introduction unit 14 is started. In this case, the control unit 20 stores the purge gas introduction period as one of the conditions of the regeneration process.

[0036] Alternatively, the control unit 20 may change the state of the purge gas introduction unit 14 from on to off based on at least one of the first temperature and the second temperature. For example, when the control unit 20 changes the state of the purge gas introduction unit 14 based only on the first temperature, the control unit 20 may change the state of the purge gas introduction unit 14 from on to off on condition that the first temperature is equal to or higher than the third set temperature. In this case, the control unit 20 stores the third set temperature as one of the conditions for the regeneration process. Alternatively, when the control unit 20 changes the state of the purge gas introduction unit 14 based only on the second temperature, the control unit 20 may change the state of the purge gas introduction unit 14 from on to off on condition that the second temperature is equal to or higher than the fourth set temperature. In this case, the control unit 20 stores the fourth set temperature as one of the conditions for the regeneration process.

[0037] Alternatively, the control unit 20 may change the state of the purge gas introduction unit 14 based on both the first temperature and the second temperature. In this case, the control unit 20 changes the state of the purge gas introduction unit 14 from ON to OFF on the condition that the first temperature is equal to or higher than the third set temperature and the second temperature is equal to or higher than the fourth set temperature. The control unit 20 stores the third set temperature and the fourth set temperature as conditions for the regeneration process.

[0038] The first set temperature may be, for example, 100° C. or more and 320° C. or less. The second set temperature may be, for example, 90° C. or more and 320° C. or less. The third set temperature may be, for example, 290° C. or more and 320° C. or less. The fourth set temperature may be, for example, 290° C. or more and 320° C. or less.

[0039] [How to regenerate a cryopump] A method for regenerating a cryopump will now be described with reference to FIGS. The method of regenerating the cryopump 10 of the present disclosure includes heating the inside of the pump case 12 and introducing a purge gas into the pump case 12. Heating the inside of the pump case 12 includes heating the inside of the pump case 12 by a heating unit 13 configured to be able to heat the inside of the pump case 12 included in the cryopump 10. Heating the inside of the pump case 12 includes not introducing a purge gas into the pump case 12. Introducing a purge gas into the pump case 12 includes introducing a purge gas into the pump case 12 after starting to heat the inside of the pump case 12 by the heating unit 13.

[0040] According to the regenerating method for cryopump 10 of the present disclosure, purge gas is introduced into pump case 12 heated by heating unit 13, so that the introduction of purge gas is less likely to cause a drop in temperature on the surface of pump case 12. This reduces the deviation of the temperature on the surface of pump case 12 from the dew point, i.e., reduces the degree to which the temperature on the surface of pump case 12 falls below the dew point, thereby reducing condensation on the surface of pump case 12. The regenerating method for cryopump 10 will be described in more detail below with reference to the drawings.

[0041] FIG. 2 is a timing chart showing the timing at which the heating unit 13 is switched on and off and the timing at which the purge gas introduction unit 14 is switched on and off in this embodiment.

[0042] 2, at timing T1, the state of the heating unit 13 is changed from off to on, thereby starting heating the inside of the pump case 12 by the heating unit 13. At timing T1, the purge gas introduction unit 14 is in the off state, i.e., in the closed state, and therefore no purge gas is introduced into the pump case 12.

[0043] As described above, the heating unit 13 can heat both the first stage 11A and the second stage 11B. Therefore, by heating the inside of the pump case 12, the first stage 11A and the second stage 11B of the refrigerator 11 are heated, thereby heating the inside of the pump case 12. In this way, since both the first stage 11A and the second stage 11B are heated, the temperature inside the pump case 12 is more likely to increase than when only one of the two stages 11A, 11B is heated.

[0044] Next, at timing T2, the state of the purge gas introduction unit 14 is changed from off to on. This starts the introduction of purge gas into the pump case 12. Note that the purge gas introduction unit 14 is maintained in the off state during the period from timing T1 to timing T2. Also, at timing T2, the heating unit 13 is continuously maintained in the on state from timing T1. The flow rate of the purge gas may be, for example, 5 slm or more and 300 slm or less. Also, the introduction side pressure of the purge gas may be, for example, 0.1 MPaG or more and 0.6 MPaG or less.

[0045] The heating period from the timing T1 to the timing T2 may be set to a predetermined period as described above, or the timing T2 may be determined based on at least one of the first temperature and the second temperature.

[0046] Next, at timing T3, the state of the purge gas introduction unit 14 is changed from on to off, thereby stopping the introduction of purge gas into the pump case 12. Also, at timing T3, the state of the heating unit 13 is changed from on to off, thereby stopping the heating of the inside of the pump case 12 by the heating unit 13.

[0047] The purge gas introduction period from the timing T2 to the timing T3 may be set to a predetermined period, or the timing T3 may be determined based on at least one of the first temperature and the second temperature.

[0048] In this manner, in the regeneration method of the present embodiment, the heating of the inside of the pump case 12 by the heating unit 13 is stopped after starting the introduction of the purge gas into the pump case 12. Therefore, since the regeneration method includes a period during which both the introduction of the purge gas into the pump case 12 and the heating of the inside of the pump case 12 by the heating unit 13 are performed, the temperature inside the pump case 12 is likely to increase.

[0049] Heating the inside of the pump case 12 may include a heating period in which the inside of the pump case 12 is heated by the heating unit 13 before the purge gas is introduced, being longer than a purge gas introduction period in which the purge gas is introduced. The heating period is an example of a first period, and the purge gas introduction period is an example of a second period. That is, the period from timing T1 to timing T2 may be longer than the period from timing T2 to timing T3. By making the heating period longer than the purge gas introduction period, the purge gas is introduced into the pump case 12 that has been sufficiently heated by the heating unit 13. This makes it more difficult for the temperature on the surface of the pump case 12 to decrease due to the introduction of the purge gas.

[0050] Fig. 3 is a timing chart showing the transition of the first temperature, the second temperature, and the temperature at the surface of the pump case 12 in this embodiment. The temperature at the surface of the pump case 12 is a temperature measured at the surface of the second cylindrical portion 12B of the surface of the pump case 12. In Fig. 3, the temperature of the first stage 11A is indicated by a dashed line, the temperature of the second stage 11B is indicated by a dashed double-dashed line, and the temperature at the surface of the pump case 12 is indicated by a solid line.

[0051] 3, heating by the heating unit 13 starts at timing T1, which causes both the first temperature and the second temperature to rise. However, since the introduction of purge gas is not started at timing T1, the area heated by the heating unit 13 is limited to a local area within the pump case 12. As a result, before the introduction of purge gas starts, the temperature at the surface of the pump case 12 hardly changes. Between timing T1 and timing T2, the rate of increase in the first temperature and the rate of increase in the second temperature are higher than the rate of increase in the temperature at the surface of the pump case 12.

[0052] At timing T2, the introduction of the purge gas begins, which further increases the first temperature and the second temperature. By introducing the purge gas, each stage 11A, 11B is heated by the purge gas in addition to being heated by the heating unit 13. Therefore, the rate of increase in each temperature from timing T2 to timing T3 is higher than the rate of increase in each temperature from timing T1 to timing T2.

[0053] At timing T2, after the inside of the pump case 12 is heated by the heating unit 13, the purge gas is introduced into the pump case 12. Therefore, even if the purge gas, which has been cooled to a temperature lower than the temperature of the pump case 12 by a member inside the pump case 12, comes into contact with the pump case 12, the temperature on the surface of the pump case 12 is unlikely to decrease. Therefore, the temperature on the surface of the pump case 12 is unlikely to fall below the dew point.

[0054] FIG. 4 is a timing chart showing the timing at which the heating unit 13 is switched on and off and the timing at which the purge gas introduction unit 14 is switched on and off in a reference example.

[0055] 4, at timing t1, the state of the heating unit 13 is changed from off to on, and the state of the purge gas introduction unit 14 is changed from off to on. As a result, the heating unit 13 starts heating the inside of the pump case 12, and at the same time, the purge gas introduction unit 14 starts introducing purge gas into the pump case 12. Next, at timing t2, the state of the heating unit 13 is changed from on to off, and the state of the purge gas introduction unit 14 is changed from on to off.

[0056] Fig. 5 is a timing chart showing the transition of the first temperature, the second temperature, and the temperature at the surface of the pump case 12 in a reference example. The temperature at the surface of the pump case 12 is a temperature measured at the surface of the second cylindrical portion 12B of the surface of the pump case 12. In Fig. 5, the temperature of the first stage 11A is indicated by a dashed line, the temperature of the second stage 11B is indicated by a dashed double-dashed line, and the temperature at the surface of the pump case 12 is indicated by a solid line.

[0057] 5, at timing t1, heating by the heating unit 13 and introduction of the purge gas are performed simultaneously. Therefore, the purge gas heated by the heating unit 13 is easily supplied to each stage 11A, 11B, and this causes the temperature of each stage 11A, 11B to rise sharply. At the same time, the purge gas cooled by the members inside the pump case 12 cools the pump case 12, so that the temperature on the surface of the pump case 12 drops. As a result, the temperature on the surface of the pump case 12 falls below the dew point, and condensation occurs on the surface of the pump case 12.

[0058] [Test example] A test example will be described with reference to FIGS. [Test Example 1] The cryopump was driven with the temperature of the first stage 11A set to 100K and the temperature of the second stage 11B set to 15K. Next, after stopping the driving of the cryopump, the state of the heating unit 13 was changed from off to on. 12 minutes after the state of the heating unit 13 was changed to on, when the temperature of the first stage 11A was 197K and the temperature of the second stage 11B was 223K, the state of the purge gas introduction unit 14 was changed from off to on. At this time, nitrogen gas was used as the purge gas, and the introduction side pressure of the purge gas was set to 0.6 MPaG. At the same time that the state of the purge gas introduction unit 14 was changed from off to on, the state of the purge gas discharge unit 17 was changed from off to on.

[0059] [Test Example 2] The cryopump was regenerated in the same manner as in Test Example 1, except that the state of the heating unit 13 was changed from off to on and the state of the purge gas introduction unit 14 was changed from off to on at the same time.

[0060] [Evaluation Results] For each test example, the temperatures measured at each part of the pump case 12 were as shown in Figures 6 and 7. For each test example, the temperatures were measured at the first stage 11A, the second stage 11B, the first cylindrical portion 12A, the second cylindrical portion 12B, the first port 12P1, and the purge gas discharge portion 17. Note that, in each test example, the temperatures at each part of the pump case 12 were continued to be measured until the temperatures of both the first stage 11A and the second stage 11B reached 300K.

[0061] In Fig. 6, the temperature of each part in Test Example 1 is indicated by a solid line, and the temperature of each part in Test Example 2 is indicated by a dashed line. In Fig. 6, the unit of the temperature of each stage 11A, 11B is "K", and the unit of the temperatures of the first cylindrical portion 12A, the second cylindrical portion 12B, the second port 12P2, and the purge gas discharge portion 17 is "°C".

[0062] 6, in Test Example 1, although the temperature rise rate of each stage 11A, 11B was lower than in Test Example 2, it was found that the temperature at each portion of the pump case 12 did not fall below 0° C. In contrast, in Test Example 2, although the temperature rise rate of each stage 11A, 11B was higher than in Test Example 1, it was found that there was a period during which the temperature of the pump case 12, other than the first cylindrical portion 12A, fell below 0° C.

[0063] 7, in Test Example 1, it was confirmed that the minimum temperature of the second cylindrical portion 12B was 5.4° C., the minimum temperature of the first cylindrical portion 12A was 11.8° C., the minimum temperature of the first port 12P1 was 6.4° C., and the minimum temperature of the purge gas discharge portion 17 was 1.4° C. In Test Example 2, it was confirmed that the minimum temperature of the second cylindrical portion 12B was −0.9° C., the minimum temperature of the first cylindrical portion 12A was 8.7° C., the minimum temperature of the first port 12P1 was −8.4° C., and the minimum temperature of the purge gas discharge portion 17 was −17.1° C.

[0064] In an environment of 23° C., the dew point is 12.0° C. when the humidity is 50%, 13.5° C. when the humidity is 55%, and 14.8° C. when the humidity is 60%. Therefore, it was found that according to Test Example 1, it is possible to reduce the deviation between the temperature and the dew point at each part of the pump case 12 compared to Test Example 2.

[0065] Furthermore, when the surface of the pump case 12 was visually observed, it was found that water droplets were formed at various locations on the surface in Test Example 2. In contrast, it was found that water droplets were not formed at various locations on the surface of the pump case 12 in Test Example 1.

[0066] As described above, according to one embodiment of the cryopump regeneration method and the cryopump, the following effects can be obtained. (1) Since the purge gas is introduced into the pump case 12 heated by the heating unit 13, the temperature on the surface of the pump case 12 is less likely to decrease due to the introduction of the purge gas. Therefore, the deviation of the temperature on the surface of the pump case 12 from the dew point is suppressed, and condensation on the surface of the pump case 12 is suppressed.

[0067] (2) Since the period includes a period during which both the introduction of purge gas into the pump case 12 and the heating of the inside of the pump case 12 by the heating unit 13 are performed, the temperature inside the pump case 12 is likely to increase.

[0068] (3) Since both the first stage 11A and the second stage 11B are heated, the temperature inside the pump case 12 is more likely to increase than when only one of the two stages 11A, 11B is heated.

[0069] (4) Since the heating period is longer than the purge gas introduction period, the purge gas is introduced into the pump case 12 that is sufficiently heated by the heating unit 13, so that the temperature on the surface of the pump case 12 is less likely to decrease due to the introduction of the purge gas.

[0070] The above-described embodiment can be modified as follows. [Heating section] The motor 11M of the refrigerator 11 may also function as a heating unit. In this case, in the method for regenerating the cryopump 10, the motor 11M of the refrigerator 11 can be used to heat the inside of the pump case 12. This makes it possible to obtain the following effects.

[0071] (5) Since the motor 11M of the refrigerator 11 also functions as a heating unit for heating the cryopump 10, the cryopump 10 does not need to be provided with a separate heating unit, so the structure of the cryopump 10 can be simplified.

[0072] When the cryopump 10 includes the above-mentioned heating unit 13, the inside of the pump case 12 may be heated by both the heating unit 13 and the motor 11M of the refrigerator 11. In this case, it is possible to increase the rate at which the temperature inside the pump case 12 rises, compared to when the inside of the pump case 12 is heated only by the heating unit 13 or only by the motor 11M.

[0073] [How to play] The purge gas introduction period may be longer than the heating period. Even in this case, it is possible to obtain the effect equivalent to the above-mentioned (1) by heating the inside of the pump case 12 with the heating unit 13 before starting the introduction of the purge gas into the pump case 12. [Explanation of symbols]

[0074] 1. Cryosystem 10…Cryo pump 11…Refrigeration unit 12…Pump case 13...Heating part 14…Purge gas inlet 20...Control section

Claims

1. Heating the inside of a pump case provided in a cryopump by a heating unit configured to be able to heat the inside of the pump case; and and introducing a purge gas into the pump case after the heating unit starts heating the inside of the pump case. How to regenerate a cryopump.

2. Heating the inside of the pump case includes stopping the heating of the inside of the pump case by the heating unit after starting the introduction of the purge gas into the pump case. The method for regenerating a cryopump according to claim 1.

3. Heating the inside of the pump case includes heating a first stage and a second stage of a refrigerator of the cryopump, thereby heating the inside of the pump case. A method for regenerating a cryopump according to claim 1 or 2.

4. Heating the inside of the pump case includes heating the inside of the pump case using a motor included in the refrigerator. The method for regenerating a cryopump according to claim 3.

5. Heating the inside of the pump case includes a first period during which the inside of the pump case is heated by the heating unit before the purge gas is introduced, the first period being longer than a second period during which the purge gas is introduced. A method for regenerating a cryopump according to claim 1 or 2.

6. a cryopump including a refrigerator, a pump case accommodating the refrigerator, a heating unit configured to be able to heat an inside of the pump case, and a purge gas introduction unit connected to the pump case; A control unit that controls the driving of the heating unit and the driving of the purge gas introduction unit, The control unit is configured to be capable of controlling the driving of the heating unit and the driving of the purge gas introduction unit so as to introduce a purge gas into the pump case after the heating unit starts heating the inside of the pump case. Cryo system.

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