removal of copper particles from silicon wafers using
UV, visible and IR radiation
Lee, C. Curran, K.G. Watkins
Group, Department of Engineering, University of Liverpool,
Liverpool L69 3GH, UK
removal of small copper particles from sili-con wafer surfaces
was carried out using Nd:YAG laser radi-ation from near-infrared
(1064 nm) through visible (532 nm) to ultraviolet (266 nm).
It has been found that both 266 nm and 532 nm are successful
in removing the particles from the surface whereas 1064
nm was shown to be ineffective in the removal of particles.
The damage-threshold laser fluence at 266 nm was much higher
than other wavelengths which provides a much wider regime
for safe cleaning of the sur-face without causing any substrate
damage. The cleaning effi-ciency was increased with a shorter
wavelength. The effect of laser wavelength in the removal
process is discussed by con-sidering the adhesion force
of the particle on the surface and the laser-induced cleaning
forces for the three wavelengths.
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