Abstract

A laser direct write system consisting of a cw Ar ion laser with UV option, an acousto-optic modulator, high-quality optics for beam expansion and steering, and a reflective objective for focusing, has been designed to etch trenches into Si with nanometer resolution. The Si substrate, mounted in a process chamber, is exposed to Cl₂ gas and heated above its melting point by the laser light. Upon melting, a fast etch reaction is initiated,¹ resulting in an etched profile that corresponds directly to the induced melt. Translating the sample by high-resolution DC motor stages with a bidirectional repeatability of 25 nm, continuous, well-defined trenches are etched into the substrate with an extremely high writing speed of up to 100 mm/s. The trench width is completely determined by the melt size. By decreasing the laser power to the minimum required for melting, we have reached trench widths of less than 150 nm.

© 1995 Optical Society of America