The excimer laser has been widely used for the removal of thin metal films.
In this work, excimer laser ablation was applied to remove chromium films
from glass substrates. To understand the removal mechanism and to seek the
optimal processing conditions for pattern generation, a one-dimensional hea
t flow model was formulated which incorporated melting and vaporization. Mo
rphological investigations were carried out experimentally on samples havin
g different chromium film thicknesses that were irradiated with a KrF excim
er laser. The thresholds for film damage, complete removal and glass damage
were determined experimentally and compared with the calculated results. T
he measured single-shot ablation rate is about twice as high as the numeric
al predictions based on a heat conduction theory. The removal mechanism of
the chromium film is found to be divided into two steps of pure vaporizatio
n and melt expulsion by vapor recoil pressure. Optimal processing condition
s were determined to enhance the accuracy and quality of film removal for p
attern generation. Finally, the slit disk of a rotary encoder was manufactu
red using the optimal processing conditions established. (C) 1999 Elsevier
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