Abstract

In general photochemical (drying etching) process of thin films based on (UV) laser-initiated chemistry is difficult to investigate both mechanistically and kinetically. Some of the most important questions are concerned with the photo-formation of the reactive species and their (reactive) chemical interaction with the surface. The UV-laser assisted etching of SiO₂ from photolysis of CH₂ CHF is quite attractive for mechanistic studies of the etching process because of the relative simple (in-situ) application of IR (time-resolved) fluorescence and absorption techniques to monitor both the HF etchant and the SiF₄ products within the gas-surface system. The strong oscillator and absorption strength of the HF molecules makes it possible to monitor its photo-production and follow the subsequent etching reaction with the SiO₂ surface. Moreover, high resolution and sensitive diode laser absorption probes can be used to investigate the surface products (SiF₄, SiF₃, SiF₂ and SiF) in the gas phase.

© 1985 Optical Society of America