| 主权项 |
1. An excimer laser system comprising:
a first excimer laser apparatus that includes a first laser chamber containing a gas, at least a pair of first electrodes disposed within the first laser chamber, and a first resonator disposed sandwiching the first laser chamber; a second excimer laser apparatus that includes a second laser chamber containing a gas, at least a pair of second electrodes disposed within the second laser chamber, and a second resonator disposed sandwiching the second laser chamber, and that amplifies laser light outputted from the first excimer laser apparatus; at least one power source unit that supplies a voltage between the first electrodes and the second electrodes; a gas supply unit, connected to a first receptacle that holds a first laser gas containing halogen gas and a second receptacle that holds a second laser gas having a lower halogen gas concentration than the first laser gas, the gas supply unit including:
a first pipe connected to the first laser chamber;a first valve provided in the first pipe;a second pipe connected to the second laser chamber;a second valve provided in the second pipe; anda third pipe connected to both the first pipe and the second pipe, at least one of the first receptacle and the second receptacle being connected to the third pipe, so that the gas supply unit supplies the first laser gas and the second laser gas to the interiors of the first laser chamber and the second laser chamber; a gas exhaust unit that partially exhausts gas from within the first laser chamber and the second laser chamber; and a gas control unit that controls the gas supply unit and the gas exhaust unit, wherein the gas control unit selectively performs: a first gas pressure control in which the gas supply unit supplies the second laser gas to the interior of the first laser chamber or the gas exhaust unit partially exhausts gas from within the first laser chamber, where the gas control unit controls the first valve to open, while the second valve being closed; a second gas pressure control in which the gas supply unit supplies the second laser gas to the interior of the second laser chamber or the gas exhaust unit partially exhausts gas from within the second laser chamber, where the gas control unit controls the second valve to open, while the first valve being closed; a first partial gas replacement control in which the gas supply unit supplies the first laser gas and the second laser gas to the interior of the first laser chamber and the gas exhaust unit partially exhausts gas from within the first laser chamber sequentially, where the gas control unit controls the first valve to open, while the second valve being closed; and a second partial gas replacement control in which the gas supply unit supplies the first laser gas and the second laser gas to the interior of the second laser chamber and the gas exhaust unit partially exhausts gas from within the second laser chamber sequentially, where the gas control unit controls the second valve to open, while the first valve being closed, wherein the gas control unit is configured to: measure a repetition rate of the laser light outputted from the first laser chamber or the second laser chamber; calculate a first time interval based on the repetition rate, the first time interval having a first length when the repetition rate has a first value, the first time interval having a second length shorter than the first length when the repetition rate has a second value larger than the first value; calculate a second time interval based on the repetition rate, the second time interval having a third length when the repetition rate has a third value, the second time interval having a fourth length shorter than the third length when the repetition rate has a fourth value larger than the third value; perform a next first partial gas replacement control when the first time interval has passed since a former first partial gas replacement control was performed; and perform a next second partial gas replacement control when the second time interval has passed since a former second partial gas replacement control was performed, wherein, in the first partial gas replacement control, the gas supply unit supplies a first amount of laser gas including the first laser gas and the second laser gas to the interior of the first laser chamber and the gas exhaust unit partially exhausts the first amount of laser gas from within the first laser chamber when the repetition rate has the first value, and the gas supply unit supplies a second amount of laser gas including the first laser gas and the second laser gas to the interior of the first laser chamber, the second amount being smaller than the first amount, and the gas exhaust unit partially exhausts the second amount of laser gas from within the first laser chamber when the repetition rate has the second value, and wherein, in the second partial gas replacement control, the gas supply unit supplies a third amount of laser gas including the first laser gas and the second laser gas to the interior of the second laser chamber and the gas exhaust unit partially exhausts the third amount of laser gas from within the second laser chamber when the repetition rate has the third value, and the gas supply unit supplies a fourth amount of laser gas including the first laser gas and the second laser gas to the interior of the second laser chamber, the fourth amount being smaller than the third amount, and the gas exhaust unit partially exhausts the fourth amount of laser gas from within the second laser chamber when the repetition rate has the fourth value. |
