Charged particle beam apparatus and control method thereof

Patent metadata

Field	Value
Publication number	US-10784074-B2
Application number	US-201615777121-A
Country	US
Kind code	B2
Filing date	Nov 29, 2016
Priority date	Dec 8, 2015
Publication date	Sep 22, 2020
Grant date	Sep 22, 2020

Abstract

The invention is directed to a charged particle beam apparatus that enables temperature maintenance in a cooling unit provided inside a vacuum application apparatus using a refrigerant. The charged particle beam apparatus includes a cooling tank that contains a refrigerant for cooling a cooling unit, a cooling pipe that supplies the refrigerant from the cooling tank to the cooling unit, and a unit that leads the refrigerant to liquefy when the refrigerant is biased to a solid.

First claim

The invention claimed is:

1. A charged particle beam apparatus for cooling a cooling unit inside a vacuum application apparatus, comprising:
a cooling tank that contains a refrigerant for cooling the cooling unit;
a cooling pipe that supplies the refrigerant from the cooling tank to the cooling unit;
a unit, comprising:
a pump configured to exhaust the interior of the cooling tank to depressurize the interior of the cooling tank;
a valve configured to inject gas into the interior of the cooling tank to pressurize the interior of the cooling tank; and
a vacuum gauge configured to measure a degree of vacuum of the interior of the cooling tank; and

a controller configured to:
control the refrigerant to liquefy when the refrigerant is biased to a solid;
control the pump and the valve to maintain the refrigerant in a solid-liquid coexisting state by pressurizing and depressurizing an interior of the cooling tank based on the degree of vacuum measured by the vacuum gauge; and
control operation of at least one of the pump and the valve when the degree of vacuum measured by the vacuum gauge is a predetermined degree of vacuum.

2. The charged particle beam apparatus according to claim 1 , wherein
the controller is configured to control the refrigerant to liquefy by pressurizing the interior of the cooling tank.

3. The charged particle beam apparatus according to claim 1 , wherein
the controller is configured to control the refrigerant to liquefy by heating the refrigerant.

4. The charged particle beam apparatus according to claim 1 , wherein
the controller is configured to control the refrigerant to liquefy by vibrating the refrigerant.

5. The charged particle beam apparatus according to claim 1 , wherein
the controller is configured to control the refrigerant to liquefy by heating the refrigerant when the refrigerant is biased to a solid, and control the refrigerant to solidify by depressurizing the interior of the cooling tank when the refrigerant is biased to a liquid.

6. The charged particle beam apparatus according to claim 1 , wherein
the controller is configured to control the refrigerant to liquefy by vibrating the refrigerant when the refrigerant is biased to a solid, and leads the refrigerant to solidify by depressurizing the cooling tank when the refrigerant is biased to a liquid.

7. The charged particle beam apparatus according to claim 5 , wherein
the unit includes a heater that heats the refrigerant.

8. The charged particle beam apparatus according to claim 6 , wherein
the unit includes a vibration generator that vibrates the refrigerant.

9. The charged particle beam apparatus according to claim 1 , wherein
the unit further includes a thermocouple that measures a temperature of the interior of the cooling tank and the controller is configured to control at least one of the pump and the valve based on the temperature measured by the thermocouple, and
the controller controls the pump and the valve when the temperature measured by the thermocouple is a predetermined temperature.

10. The charged particle beam apparatus according to claim 1 , wherein
the unit further includes a nitrogen gas cylinder that supplies a nitrogen gas through the valve, and
the controller supplies the nitrogen gas from the nitrogen gas cylinder through the valve.

11. The charged particle beam apparatus according to claim 1 , wherein
the cooling unit is disposed in the vicinity of a sample holder.

12. The charged particle beam apparatus according to claim 1 , wherein
the cooling unit is formed integrally with a sample holder.

13. A control method of a charged particle beam apparatus for cooling a cooling unit inside a vacuum application apparatus, the control method comprising steps of:
supplying a refrigerant from a cooling tank to the cooling unit, the cooling tank containing the refrigerant for cooling the cooling unit; and
controlling the refrigerant to liquefy when the refrigerant is biased to a solid;
maintaining the refrigerant in a solid-liquid coexisting state by controlling a valve to inject gas into the interior of the cooling tank to pressurize the interior of the cooling tank and controlling a pump to exhaust the interior of the cooling tank to depressurize the interior of the cooling tank based on a measured degree of vacuum; and
controlling operation of at least one of the pump and the valve when the measured degree of vacuum is a predetermined degree of vacuum.

Assignees

• Hitachi High Tech Corp

Inventors

• Sunaoshi Takeshi
• Orai Yoshihisa
• Hatano Haruhiko
• MIZUO Takashi

Classifications

• H01J2237/022

  Avoiding or removing foreign or contaminating particles, debris or deposits on sample or tube · CPC title

• H01J2237/1825

  Evacuating means · CPC title

• H01J2237/262

  Non-scanning techniques · CPC title

• H01J2237/028

  Particle traps · CPC title

• H01J2237/28

  Scanning microscopes · CPC title