Excimer laser apparatus and excimer laser system

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;
• and
• 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.

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;
• and
• a gas control unit configured to, based on a deterioration parameter of the pair of electrodes,
• control the gas supply unit and the gas exhaust unit to increase a replacement amount of gas to be replaced from within the laser chamber as the deterioration parameter changes to show that deterioration of the pair of electrodes progresses,
• output a life expiration signal when the deterioration parameter shows a life expiration of the pair of electrodes, and
• further increase the replacement amount of gas to be replaced from within the laser chamber upon receiving a life prolonging command after outputting the life expiration signal.