Method for regenerating cryopump

Abstract

A method for regenerating a cryopump that includes a cooler including a first stage part and a second stage part, and configured to cool the first stage part and the second stage part with a high pressure refrigerant; a cryopanel including a first panel which is cooled by the first stage part and a second panel which is cooled by the second stage part; a cryopump vessel configured to surround the cryopanel and including a radiation shield that surrounds the first stage part; a first heater provided in the first panel; and a second heater provided in the second panel, the method comprising a temperature increasing process of increasing temperatures of the radiation shield and the first panel by turning on the first heater, a roughing process of controlling a roughing valve configured to regulate vacuum within the cryopump vessel in a state where the cryopump vessel is kept at a pressure at which solid state ice can sublimate into gas state vapor, a purging process of supplying a purge gas into the cryopump vessel, and a cool-down process of lowering the temperatures of the first panel and the second panel.

1 . A method for regenerating a cryopump that includes a cooler including a first stage part and a second stage part, and configured to cool the first stage part and the second stage part with a high pressure refrigerant; a cryopanel including a first panel which is cooled by the first stage part and a second panel which is cooled by the second stage part; a cryopump vessel configured to surround the cryopanel and including a radiation shield that surrounds the first stage part; a first heater provided in the first panel; and a second heater provided in the second panel, the method comprising:
 a temperature increasing process of increasing temperatures of the radiation shield and the first panel by turning on the first heater;   a roughing process of controlling a roughing valve configured to regulate vacuum within the cryopump vessel in a state where the cryopump vessel is kept at a pressure at which solid state ice can sublimate into gas state vapor;   a purging process of supplying a purge gas into the cryopump vessel; and   a cool-down process of lowering the temperatures of the first panel and the second panel.   
     
     
         2 . The method for regenerating a cryopump of  claim 1 , further comprising:
 before the temperature increasing process,   stopping an operation of the cooler.   
     
     
         3 . The method for regenerating a cryopump of  claim 1 ,
 wherein the pressure at which solid state ice can sublimate into gas state vapor ranges from 10 −2  torr to 10 −3  torr.   
     
     
         4 . The method for regenerating a cryopump of  claim 3 ,
 wherein the roughing process includes:   maintaining a pressure inside the cryopump vessel to be equal to or lower than the pressure at which solid state ice can sublimate into gas state vapor by opening the roughing valve.   
     
     
         5 . The method for regenerating a cryopump of  claim 4 ,
 wherein the roughing process includes:   closing the roughing valve when the temperature of the first panel reaches a predetermined temperature after the roughing valve has been opened.   
     
     
         6 . The method for regenerating a cryopump of  claim 5 ,
 wherein the predetermined temperature ranges from 250K to 300K.   
     
     
         7 . The method for regenerating a cryopump of  claim 1 ,
 wherein the purging process includes:   maintaining the temperature of the first panel at a preset temperature by using the first heater; and   maintaining the temperature of the second panel at a preset temperature by using the second heater.