Abstract
The etching of single‐crystal silicon, CVD polysilicon, thermally grown silicon oxides, and Ni‐Cr masks have been studied using a chemical‐assisted ion beam etching (CAIBE) process. Etch rates were measured as functions of 
gas flow rate, Ar+ ion beam energy, and beam current density. Selectivities of Ni‐Cr:Si, Ni‐Cr:poly, and 
of 1:10, 1:9, and 1:4 were determined. Vertical profiles were obtained down to at least 100 nm linewidths using CAIBE.