A 26‐cm electron‐cyclotron‐resonance ion source for reactive ion beam etching of SiO2 and Si

Abstract

A 26 cm ECR ion source for reactive ion beametching has been developed for precise processing of semiconductor devices in sub‐micron range. Such fine patterns of SiO2 films on Si substrates as 0.6‐ μm width are produced precisely and anisotropically without etching residues or redeposition with c‐C4F8 as etching gas. The ECR ion source can be operated continuously for more than 40 h with C4F8plasma, as it has no hot filament. Etch rate ratio of SiO2 to Si increases with increasing C4F8 pressure. A selectivity of about 30:1 is obtained at 2×10−4 Torr. Monitoring methods such as secondary ion mass spectrometry,emission spectroscopy, and Auger electron spectroscopy were used to study the ion source characteristics and etching processes. Reactive ion beametching using ECR ion source operates with less metal contamination than Ar ion beametching.