An oxide masking technique for use in the fabrication of micro-circuits and allied devices

Abstract A description of the use and preparation of reactively sputtered Bismuth Oxide (Bi2O3) films, profiled photomechanically, for use as intermediate masks in the preparation of micro-circuits and allied devices. These masks are suitable for use with a wide range of materials both in a high vacuum and in high temperature systems up to a useful limit of 700°C. The oxide film as prepared is of fine grain structure with freedom from pinholes or occlusions. It bonds firmly to polished substrates, and at the same time is easily etched in dilute solutions of hydrochloric acid or HCl vapour irrespective of the material deposited on its surface. Maximum variations observed in edge definition do not exceed 2–3 μ, in general the definition is one order of magnitude better.