Silicon dioxide fine patterning by reactive fast atom beam etching

Abstract

A fast atom beam technique is applied to silicon dioxide substrate pattern fabrication. A modified Mcllraith (saddle field) fast atom source having a charge exchange cell in front of the cathode grid is studied under several discharge conditions. High pressure in the source is shown to increase the proportion of high-energy neutral particles in the beam. The tendencies of the neutralizations are in accordance with calculations based on resonance charge transfer. Maximum etch rates for Si and SiO2 using a CF4 +O2 gas mixture are achieved at a relative CF4 gas flow rate of 0.76, and the etch rate for SiO2, unlike that for Si, is found to depend linearly on the discharge current. The etched sidewalls at a discharge voltage of 1.2 kV were nearly perpendicular. Reactive fast atom beam etching proved capable of producing highly accurate 0.2-μm-wide pattern formations.