Abstract

The overall goal of our work is to understand etching by high-fluence excimer laser pulses. The primary experimental technique is to measure the laser-induced fluorescence (LIF) from atoms and diatomic molecules in the etch plume. One of the materials originally under Investigation¹ was sapphire, Al₂O₃. The primary conclusion is that UV photons incident on sapphire produce a high electron-hole density and consequent photochemical breakdown and ablation of the surface. Major evidence for this conclusion is that the LIF determined surface temperature Increased only to ≲500 K even at the ablation threshold, which is 800 mJ/cm² at 193 nm.

© 1988 Optical Society of America