Projection x-ray lithography with ultrathin imaging layers and selective electroless metallization

The effect of 193-nm excimer laser radiation on pellicles designed for 248-nm use is studied. The pellicles are transparent at 193 nm as well. However, prolonged irradiation causes gradual thinning and eventual rupture of the pellicle. The rate of change depends on the fluence and on the total dose but is not affected by the presence of atmospheric oxygen. Two-photon absorption plays an important role in the interaction between the laser and the pellicle material. Extrapolation to the approximately 0.1 mJ cm2/pulse fluences expected to be used in 193-nm steppers indicates that these pellicles will change little for several years in a full-production environment.