Cryopump, cryopump system, and cryopump regeneration method

1 . A cryopump comprising:

a cryopanel;

an adsorption area provided on the cryopanel and capable of adsorbing a non-condensable gas, the adsorption area including a non-combustible adsorbent containing silica gel as a main component thereof;

a cryopump housing in which the cryopanel having the adsorption area is disposed in an interior thereof;

a pressure sensor that generates a pressure measurement signal indicating an internal pressure of the cryopump housing;

a rough valve mounted to the cryopump housing and connecting the cryopump housing to a rough pump;

a memory that stores a first threshold value of pressure rise rate being a positive value and a second threshold value of pressure rise rate being a negative value; being smaller than the first threshold value; and

a regeneration controller configured to:

open the rough valve for a certain opening period in regeneration of the cryopump, wherein the rough valve remains continuously open throughout the certain opening period,

receive a first pressure measurement signal from the pressure sensor measured during the certain opening period of the rough valve,

compare a first pressure rise rate of the cryopump housing with the first threshold value based on the first pressure measurement signal,

receive a second pressure measurement signal from the pressure sensor after it is determined that the first pressure rise rate is larger than the first threshold value based on the comparison, wherein the second pressure measurement signal is measured during the certain opening period of the rough valve,

compare a second pressure rise rate of the cryopump housing with the second threshold value based on the second pressure measurement signal, and

close the rough valve when the second pressure rise rate is smaller than the second threshold value.

2 . The cryopump according to claim 1 , wherein the silica gel has an average pore size in a range of 0.5 nm to 3.0 nm.

3 . The cryopump according to claim 1 , wherein the silica gel has an average pore size in a range of 2.0 nm to 3.0 nm.

4 . The cryopump according to claim 1 , wherein the adsorption area does not contain activated carbon.

5 . The cryopump according to claim 1 , wherein the regeneration controller comprises:

a first pressure rise rate monitor that receives the first pressure measurement signal measured during the certain opening period of the rough valve and compares the first pressure rise rate with the first threshold value based on the first pressure measurement signal;

a second pressure rise rate monitor that receives the second pressure measurement signal measured during the certain opening period of the rough value and compares the second pressure rise rate with the second threshold value based on the second pressure measurement signal, on a condition that the first pressure rise rate monitor determines that the first pressure rise rate is larger than the first threshold value; and

a rough valve driver that closes the rough valve, on a condition that the second pressure rise rate monitor determines that the second pressure rise rate is smaller than the second threshold value, as one condition.

6 . The cryopump according to claim 5 , further comprising:

a condensation cryopanel that is disposed in the cryopump housing and cooled to a higher temperature than the cryopanel having the adsorption area;

a temperature sensor that generates a temperature measurement signal indicating a measured temperature of either the condensation cryopanel or the cryopanel having the adsorption area;

a purge valve mounted to the cryopump housing and connecting the cryopump housing to a purge gas source;

a temperature monitor that receives the temperature measurement signal and compares the measured temperature with a purge stop temperature; and

a purge valve driver that opens the purge valve when the regeneration of the cryopump is started, and closes the purge valve on a condition that the temperature monitor determines that the measured temperature is higher than the purge stop temperature,

wherein the rough valve driver opens the rough valve on a condition that the temperature monitor determines that the measured temperature is higher than the purge stop temperature, and

the purge stop temperature is set to a temperature value lower than a triple point temperature of water.

7 . The cryopump according to claim 5 , wherein the rough valve driver closes the rough valve on an additional condition that the internal pressure of the cryopump housing is lower than a pressure threshold value.

8 . The cryopump according to claim 5 , wherein the rough valve driver closes the rough valve on an additional condition that a temperature in the cryopump housing is higher than a temperature threshold value.

9 . The cryopump according to claim 1 , wherein the regeneration controller increases a temperature of the adsorption area to 65° C. or higher during regeneration.

10 . The cryopump according to claim 1 , further comprising:

a compressor,

wherein the cryopump operates to vaporize and discharge ice condensed in the cryopump by sublimation during abnormal stop of the compressor.

11 . A cryopump system comprising:

the cryopump according to claim 1 ; and

at least one other cryopump;

wherein the rough pump is common to the cryopump and the at least one other cryopump;

wherein the regeneration controller receives a regeneration start command for each of the cryopumps and starts the regeneration of the cryopump, and

wherein the regeneration controller delays the regeneration start of the at least one other cryopump until after the regeneration of the cryopump is completed, in a case where the regeneration controller receives the regeneration start command for the at least one other cryopump, during the regeneration of the cryopump.

12 . The cryopump according to claim 1 , further comprising:

a condensation cryopanel that is disposed in the cryopump housing and cooled to a higher temperature than the cryopanel having the adsorption area;

a temperature sensor that generates a temperature measurement signal indicating a measured temperature of either the condensation cryopanel or the cryopanel having the adsorption area;

a purge valve mounted to the cryopump housing and connecting the cryopump housing to a purge gas source;

wherein the memory further stores a purge stop temperature being lower than a triple point temperature of water,

wherein the regeneration controller is further configured to:

prior to the opening of the rough valve for the certain opening period, open the purge valve, receive the temperature measurement signal from the temperature sensor, and compare the measured temperature with the purge stop temperature based on the temperature measurement signal, and

close the purge valve and start the opening of the rough valve for the certain opening period when the measured temperature is higher than the purge stop temperature.

13 . The cryopump according to claim 12 , wherein the purge stop temperature is selected from a range of 230 K to 270 K.

14 . The cryopump according to claim 6 , wherein the purge stop temperature is selected from a range of 230 K to 270 K.