BUMP FORMATION AND GROWTH BY MULTIPLE LASER-PULSES ON NI-P DISK SUBSTRATE

Multiple pulse exposure provides a means for making bumps in the 1-100 nm height range on NI-P substrates. Although the bump height is gener ally a nonlinear function of the number of pulses, below the fluence t hreshold for chemicapillary effects, bump height increases linearly wi th the number of pulses. At low fluence levels, when the peak melt tem perature is below 1400 degrees K, the bump surface becomes rough. Avoi ding the low fluence regime, this technique can be reliably used for m aking smooth bumps with flexible shapes and sizes which are useful for tribology studies.