200-mW continuous-wave laser source at 198.5 nm for lithographic applications

We report on the development and testing of a laser system that delivers up to 200 mW of continuous-wave radiation at 198.54 nm in a near diffraction-limited beam, to be used as a source for photolithography mask writing and mask inspection. The source has been developed with the support of International SEMATECH. The laser output is obtained by intra-cavity sum frequency generation in a CLBO (Cesium Lithium Borate) non-linear crystal