Anisotropic Wet Etching of Aluminum Electrodes by an Evacuated Etching System

Abstract

Wet etching of Al/Si (2%) films for fine pattern engraving has been studied using an evacuated wet etching system. The results indicate that isotropic etching by conventional atmospheric wet etching changes to quasi‐anisotropic etching with decreasing pressure. The amount of lateral etching beneath the photoresist pattern, which is around 0.8 μm in conventional atmospheric wet etching, decreases with decreasing pressure and reaches 0.42 μm at a pressure of 9 torr. Uniformity of lateral etching is much better than that by conventional wet and dry etching. This technique is useful in the manufacture of fine‐pattern aluminum electrodes, for instance, with 1.0–1.2 μm linewidths.