ULTRAVIOLET LASER ABLATION OF ORGANIC POLYMER FILMS.

Abstract

When a pulse (approximately 14 nsec half-width) of laser radiation of 193 nm wavelength with a fluence above a threshold value falls on a polymer film, the material at the irradiation site is spontaneously etched away to a depth of 1000 Amstrong or more. This process has been called Ablative Photo Decomposition. The excimer laser which is the source of the 193 nm radiation is capable of providing radiation at other wavelengths such as 249 nm, 308 nm, and 351 nm. Spontaneous etching of the polymer films by the laser beam has been observed at all of these wavelengths. But there are quantitative differences in the etching process at different wavelengths and with different polymers. This review is meant to be: (i) an introduction to UV laser ablation of organic polymer films, (ii) a critical analysis of published data on the subject to point out the directions in which further research can be undertaken, and (iii) a discussion of the mechanisms which have been proposed to explain UV laser ablation.