Cryopump and method for controlling cryopump

1. A cryopump comprising:

a first-stage cryopanel;

a second-stage cryopanel;

a cryocooler thermally coupled to the first-stage cryopanel and the second-stage cryopanel to cool the first-stage cryopanel to a first-stage cooling temperature and cool the second-stage cryopanel to a second-stage cooling temperature that is lower than the first-stage cooling temperature;

a first temperature sensor configured to measure the first-stage cooling temperature;

a second temperature sensor configured to measure the second-stage cooling temperature; and

a cryocooler controller connected to the first temperature sensor and the second temperature sensor to receive the first-stage cooling temperature and the second-stage cooling temperature measured by the first temperature sensor and the second temperature sensor, respectively,

wherein the cryocooler controller configured to:

execute a first-stage temperature control for controlling the first-stage cooling temperature to a first-stage target temperature;

increase cooling capacity of the cryocooler when an increase in the second-stage cooling temperature is detected during the execution of the first-stage temperature control;

execute the first-stage temperature control and a second-stage temperature control for controlling the second-stage cooling temperature to a second-stage target temperature; and

switch from the first-stage temperature control to the second-stage temperature control when an increase in the second-stage cooling temperature is detected during the execution of the first-stage temperature control,

wherein the cryocooler controller includes:

a second-stage temperature monitor configured to:

determine whether or not the second-stage cooling temperature exceeds a predetermined second-stage upper limit temperature, during the execution of the first-stage temperature control, and

a temperature controller configured to:

execute the first-stage temperature control and the second-stage temperature control; and

switch from the first-stage temperature control to the second-stage temperature control in a case where the second-stage cooling temperature exceeds the predetermined second-stage upper limit temperature during the execution of the first-stage temperature control.

2. The cryopump according to claim 1 , wherein the temperature controller configured to continue the first-stage temperature control in a case where the second-stage cooling temperature is equal to or lower than the predetermined second-stage upper limit temperature during the execution of the first-stage temperature control.

3. The cryopump according to claim 1 , wherein the cryocooler controller includes a first-stage temperature monitor configured to determine whether or not the first-stage cooling temperature falls below a predetermined first-stage lower limit temperature, during the execution of the second-stage temperature control, and

the temperature controller is configured to switch from the second-stage temperature control to the first-stage temperature control in a case where the first-stage cooling temperature falls below the predetermined first-stage lower limit temperature.

4. The cryopump according to claim 3 , wherein the temperature controller is configured to continue the second-stage temperature control in a case where the first-stage cooling temperature is equal to or higher than the predetermined first-stage lower limit temperature during the execution of the second-stage temperature control.

5. The cryopump according to claim 1 , wherein the cryocooler controller is configured to notify a user of switching from the first-stage temperature control to the second-stage temperature control.

6. The cryopump according to claim 1 , wherein the cryocooler controller is configured to lower the first-stage target temperature when an increase in the second-stage cooling temperature is detected during the execution of the first-stage temperature control.

7. A method for controlling a cryopump, the cryopump including a first-stage cryopanel, a second-stage cryopanel, and a cryocooler thermally coupled to the first-stage cryopanel and the second-stage cryopanel to cool the first-stage cryopanel to a first-stage cooling temperature and cool the second-stage cryopanel to a second-stage cooling temperature that is lower than the first-stage cooling temperature,

the method comprising:

executing first-stage temperature control for controlling the first-stage cooling temperature to a first-stage target temperature; and

increasing cooling capacity of the cryocooler when an increase in the second-stage cooling temperature is detected during the execution of the first-stage temperature control,

wherein the increasing comprises:

switching from the first-stage temperature control to a second-stage temperature control for controlling the second-stage cooling temperature to a second-stage target temperature when an increase in the second-stage cooling temperature is detected during the execution of the first-stage temperature control,

wherein the switching comprises:

determining whether or not the second-stage cooling temperature exceeds a predetermined second-stage upper limit temperature, during the execution of the first-stage temperature control, and

switching from the first-stage temperature control to the second-stage temperature control in a case where the second-stage cooling temperature exceeds the predetermined second-stage upper limit temperature during the execution of the first-stage temperature control.

8. A cryopump comprising:

a first-stage cryopanel;

a second-stage cryopanel;

a cryocooler thermally coupled to the first-stage cryopanel and the second-stage cryopanel to cool the first-stage cryopanel to a first-stage cooling temperature and cool the second-stage cryopanel to a second-stage cooling temperature that is lower than the first-stage cooling temperature;

a first temperature sensor configured to measure the first-stage cooling temperature;

a second temperature sensor configured to measure the second-stage cooling temperature; and

a cryocooler controller connected to the first temperature sensor and the second temperature sensor to receive the first-stage cooling temperature and the second-stage cooling temperature measured by the first temperature sensor and the second temperature sensor, respectively, the cryocooler controller configured to:

execute a second-stage temperature control for controlling the second-stage cooling temperature to a second-stage target temperature; and

determine whether or not the first-stage cooling temperature is in a temperature range between a predetermined first-stage lower limit temperature and a predetermined first-stage upper limit temperature, during the execution of the second-stage temperature control.

9. The cryopump according to claim 8 , wherein the cryocooler controller is configured to switch from the second-stage temperature control to a first-stage temperature control for controlling the first-stage cooling temperature to a first-stage target temperature in a case where the first-stage cooling temperature falls below the first-stage lower limit temperature.

10. The cryopump according to claim 8 , wherein the cryocooler controller is configured to switch from the second-stage temperature control to a first-stage temperature control for controlling the first-stage cooling temperature to a first-stage target temperature in a case where the first-stage cooling temperature exceeds the first-stage upper limit temperature.