System and method for high accuracy gas refill in a two chamber gas discharge laser system

摘要

Systems and methods for automatically performing a high accuracy gas refill in a laser chamber of a two chamber gas discharge laser such as an excimer laser are disclosed. Based upon a target pressure and halogen concentration that is either predetermined or entered by a user, and with no further user action, a non-halogen containing gas is added to the chamber to a first pressure, followed by the addition of halogen containing gas to a second pressure which is greater than a target pressure for the chamber, such that the halogen content in the gas at the second pressure is at a desired concentration. The gas in the chamber is bled until the pressure drops to the target pressure. The amount of non-halogen containing gas added is estimated automatically, and the amount of halogen containing gas is measured so that the desired concentration is obtained, taking into account both temperature and any gas remaining in the fill pipes from prior laser operation.

主权项

1. A dual chamber gas discharge laser light source, comprising:
a master oscillator having a laser chamber containing a lasing medium as comprising a halogen; an amplifier having a laser chamber containing a lasing medium gas comprising a halogen; a gas refill system including a controller automatically executing a refill scheme, the refill scheme comprising in sequence the steps of: obtaining a target pressure and a target concentration of halogen for a selected one of the laser chambers; evacuating the selected laser chamber to a first point at which the gas pressure in the chamber reaches a predetermined low value, and measuring the temperature and pressure at the first point; adding an amount of non-halogen containing gas to the selected laser chamber to reach a second point and measuring the temperature and pressure at the second point; adding an amount of halogen containing as to the selected laser chamber such that the gas in the selected laser chamber reaches the target concentration of halogen at a pressure greater than the target pressure; and bleeding gas from the selected laser chamber until the target pressure is reached.