A step-like decrease of the output energy of an ArF excimer laser for microlithography has been observed during high-repetition rate and high-power operation. The reason for the step-like energy decrease was traced to oxygen by adding 50ppm of various gas impurities to the laser gas. It is supposed that the energy decrease is caused by laser light absorption due to the oxygen or to some kinds of oxygen compounds because no change was observed in ArF and XeF emission intensities which were monitored as measures of excimer formation, Xe content, and discharge states.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)