Abstract

Photoetching with excimer laser radiation has been an active area of research since its discovery by Srinivasan in 1982.^1,2 The apparently low thermal damage associated with these lasers has been attributed to the fact that ablation is caused by direct bond-breaking of the long chain polymer links, in which excess energy is carried away by smaller volatile fragments. There is, however, still a controversial discussion about the mechanism, and a thermal model has been suggested³ which may contribute to the degradation of the polymer. But so far the dynamics of ablative photodecomposition has not yet been studied experimentally on a picosecond time scale. In the present work results of a picosecond ablation study on polyimide will be reported and discussed in terms of a time-dependent absorption model.

© 1986 Optical Society of America