| 摘要 |
PURPOSE:To enhance an ArF laser in output by a method wherein the temperature of laser gas is monitored by a temperature sensor, and the flow rate of the cooling water of a heat exchanger or a current which flows through a heater is controlled according to the gas temperature. CONSTITUTION:A heat exchanger 7 is provided inside a laser chamber 1, a cooling water 8 is made to flow through the heat exchanger 7 to cool laser gas. A temperature sensor 9 provided in the laser chamber 1 detects the temperature of the laser gas, and the detected value is inputted into a control circuit 13. The control circuit 13 controls a flow rate control valve 12 so as to increase the cooling water 8 in flow rate when the laser gas rises in temperature or to decrease the cooling water 8 in flow rate when the laser gas falls in temperature. At this point, the laser chamber 1 is kept constant in temperature through a heater 6 mounted around the laser chamber 1. By this setup, an ArF laser can be increased and stabilized in output and oscillation efficiency independent of the influence of the change of ambient temperature and the set oscillation repetition rate. |
