Abstract

Some effects of UV-laser ablation of polymeric materials are well studied. Among them are material removal, the formation of self organized periodic surface structures in the nano- and micrometer range and the ablation process itself¹. This contribution will focus on the relatively new field of deposition of ablation products both onto an extra substrate (pulsed laser deposition) and back onto the laser irradiated sample (re-deposition). In a detailed study it was observed that this type of material is of high importance in different fields such as the laser induced permanent conductivity enhancement of polyimides, the formation of branched self-similar surface structures (dendrites) on polyesters and on the pulsed laser deposition of PTFE (Teflon™). We want to present new results on such deposited surfaces investigated by XPS, AFM, SEM, RBS, IR- and UV-Vis- spectroscopy. The formation of carbon nano-wires (about 80 nm wide and several micrometers long) on polyimide substrates will be demonstrated and explained on the basis of carbon nano-clusters redeposited and/or formed on the surface. The well defined nano-roughness of several 10 nm in height covering the whole irradiated surface area of PET (Fig. a) will be discussed on the basis of ablation products redeposited and partly embedded into the amorphized ablation area. Sperulitic crystal growth (Fig. b) in laser-deposited PTFE-films onto silicon substrates will be examined² and their relation to the good electrical quality of these films with low dielectric constant and low conductivity together with high thermal stability will be discussed.

© 1998 IEEE