As integrated circuitry becomes increasingly complex, the semiconductor industry continues to be driven towards the use of ever shorter exposure and inspection wavelengths to enable smaller feature sizes via optical lithography.

This ongoing trend in turn provides an incentive for the development of new laser light sources to generate the required short optical wavelengths.

A continuous-wave laser system capable of delivering more than 100 milliwatts of near-diffraction-limited output at a nominal wavelength of 198 nm has been developed by Coherent Laser Group with the support of International SeMaTech. The desired ultraviolet (uv) wavelength is obtained by sum-frequency mixing several hundred milliwatts of 244-nm pump light provided by either a frequency-doubled argon-ion laser or the equivalent output from a novel all-solid-state laser system (based upon optically pumped semiconductor technology) with several hundred watts of 1064-nm light circulating within a high-Q diode-pumped Nd:vanadate laser resonator.

The overall laser system performance and operating characteristics will be described. In addition, ongoing observations of photo-induced damage in several materials commonly employed for uv-wavelength optical components will also be reviewed.

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