Photoablation of polymers at 193 nm: Shot-to-shot study of emission spectra, etch depths, and transmission

Abstract

Excimer laser pulses (193 nm) were used to photoablate graphite and polymers: polymethylmethacrylate (PMMA) and polycarbonate (PC) in a vacuum (∼10−5 Torr). The resulting emission spectra were obtained on a shot-to-shot basis in the 375–520 nm wavelength range. The relative and absolute intensities of most transitions are a function of the number of laser shots. Etch profiles were measured as a function of the number of shots. The etch depth was almost linear with number of shots for the first 30 shots. The transmittance of the polymers in the range of 350–800 nm was measured as a function of number of shots and showed a minimum for PMMA.