ArF Excimer Laser Patterning of Plasma-Deposited Silicon Nitride Films: Mechanisms of Dehydrogenation.

By exposing plasma-deposited silicon nitride films to 193 nm ArF laser radiation, we were able to alter its reactivity with hydrofluoric acid solution, and etch 0.23micron features into the films. Using Fourier transform infrared spectroscopy, we show that pulsed ArF excimer laser irradiation of plasma- deposited silicon nitride films causes a large reduction in NH(~100%) and SiH (~50%) in the top ~500angstroms, and further show that this is responsible for the large suppression of the etch rate in buffered HF solution. Temperature rise calculations qualitatively predict the observed maximum falloff in etch rate and Si-H and N-H concentration at the surface of the film.