Conducting layers on KrF excimer-laser-irradiated polyimide film surfaces w
ere investigated by XPS, SEM and Fourier transform infrared (FTIR)-Raman sp
ectroscopy, Analysis of polyimide residue after laser irradiation provided
valuable insight into the nature of the formation of conducting layers. The
subtle different between KrF laser irradiation and the pyrolysis of polyim
ide was found by comparison of the formation process of conducting layers.
A physical picture was presented to describe better the formation of conduc
ting layers. Under KrF laser irradiation, polyimide films underwent thermal
decomposition assisted by photoinduced direct bond breaking. Polycrystalli
ne graphite was subsequently formed as the product of the secondary additio
n reaction of carbon-enriched clusters, Such reaction was supported by the
remaining energy on the irradiated polyimide film surface. This result show
s that the thermal process played an important role that was not just restr
icted to the formation of conducting layers, Copyright (C) 2000 John Wiley
& Sons, Ltd.