Implementation and performance of a femtosecond laser mask repair system in manufacturing

Current laser based tools for removing Cr defects are fundamentally limited due to the thermal nature of ablation carried out with nanosecond pulses. Conversely, ablation carried out with femtosecond pulses of light removes Cr in a non-thermal process. As a result, the problems of metal splatter, haze, reduced transmission and pitting of the underlying quartz common to nanosecond ablation are virtually nonexistent with femtosecond ablation of Cr. In this paper we describe a femtosecond pulsed laser mask repair system which is presently operating successfully in a manufacturing environment.