Excimer laser apparatus and excimer laser system

• US 9,837,780 B2
• Filed: 05/10/2016
• Issued: 12/05/2017
• Est. Priority Date: 12/25/2013
• Status: Active Grant

• Current Assignee: Gigaphoton, Inc. (Komatsu)
• Original Assignee: Gigaphoton, Inc. (Komatsu)
• Inventors: Asayama, Takeshi, Wakabayashi, Osamu, Kakizaki, Kouji
• Primary Examiner(s): VAN ROY, TOD THOMAS
• Application Number:
  US15/150,800
• Publication Number:
  US 20160254634A1
• Time in Patent Office: 574 Days
• CPC Class Codes: H01S 3/036 Means for obtaining or maintaining the desired gas pressure within the tube, e.g. by gettering, replenishing; Means for circulating the gas, e.g. for equalising the pressure within the tube H01S3/031 takes precedence
• CPC Class Codes: H01S 3/038 Electrodes, e.g. special shape, configuration or composition
• CPC Class Codes: H01S 3/134 in gas lasers
• CPC Class Codes: H01S 3/225 comprising an excimer or exciplex

Abstract

The excimer laser apparatus may include a laser chamber configured to contain gas, a pair of electrodes provided in the laser chamber, a power source unit configured to supply a pulse voltage between the pair of electrodes, a gas supply unit configured to supply gas into the laser chamber, a gas exhaust unit configured to partially exhaust gas from within the laser chamber, and a gas control unit configured to control the gas supply unit and the gas exhaust unit, where a replacement ratio of gas to be replaced from within the laser chamber increases as deterioration of the pair of electrodes progresses, the deterioration being represented by a deterioration parameter of the pair of electrodes.

Claims

1. An excimer laser apparatus comprising:

a laser chamber configured to contain gas;

a pair of electrodes provided in the laser chamber;

a power source unit configured to supply a pulse voltage between the pair of electrodes;

a gas supply unit configured to supply gas into the laser chamber;

a gas exhaust unit configured to partially exhaust gas from within the laser chamber;

a gas control unit configured to control the gas supply unit and the gas exhaust unit, where a replacement ratio of gas to be replaced from within the laser chamber increases as deterioration of the pair of electrodes progresses, the deterioration being represented by a deterioration parameter of the pair of electrodes, the deterioration parameter being an integrated value of input energy having been inputted to the pair of electrodes since the pair of electrodes was installed in the laser chamber;

an input unit configured to input an initial value of the integrated value of input energy; and

a laser control unit configured to add, to the initial value, a value of input energy additionally inputted to the pair of electrodes.

2. The excimer laser apparatus according to claim 1, wherein

the gas control unit is configured to determine a replacement amount of gas to be replaced from within the laser chamber based on the deterioration parameter of the pair of electrodes, and

the gas control unit is configured to control the gas supply unit and the gas exhaust unit to replace the replacement amount of gas thus determined from within the laser chamber.

3. The excimer laser apparatus according to claim 1, wherein

the gas control unit is configured to determine a time interval of gas replacement from within the laser chamber based on the deterioration parameter of the pair of electrodes, and

the gas control unit is configured to control the gas supply unit and the gas exhaust unit to replace gas at the time interval thus determined.

4. An excimer laser apparatus comprising:

a laser chamber configured to contain gas;

a pair of electrodes provided in the laser chamber;

a power source unit configured to supply a pulse voltage between the pair of electrodes;

a gas supply unit configured to supply gas into the laser chamber;

a gas exhaust unit configured to partially exhaust gas from within the laser chamber;

a gas control unit configured to

control the gas supply unit and the gas exhaust unit to replace a first amount of gas corresponding to a first ratio to the total amount of gas in the laser chamber when a deterioration parameter of the pair of electrodes has a first value,

control the gas supply unit and the gas exhaust unit to replace a second amount of gas corresponding to a second ratio to the total amount of gas in the laser chamber when the deterioration parameter of the pair of electrodes has a second value, the second ratio being higher than the first ratio, and the second value representing more progressed deterioration of the pair of electrodes than the first value, the deterioration parameter being an integrated value of input energy having been inputted to the pair of electrodes since the pair of electrodes was installed in the laser chamber;

an input unit configured to input an initial value of the integrated value of input energy; and

a laser control unit configured to add, to the initial value, a value of input energy additionally inputted to the pair of electrodes.