We have developed a new gas purifier for ArF excimer lasers that can r
emove all the impurities from degraded ArF excimer laser gas. We found
that cooled activated charcoal at temperatures below -50 degrees C ef
fectively removes CF4, which is the preponderant impurity generated in
ArF excimer laser gas mixtures. We also demonstrated that the new gas
purifier can regenerate the ArF excimer laser gas up to its initial p
urity level after about 1X10(9) shots of operation. (C) 1996 American
Institute of Physics.