Quantitative Examination of Photofabricated Profiles Part 6: High Depth to Width Ratio Profiles in (110) Silicon Produced by Anisotropic Photoetching

Abstract

. In conventional isotropic photoetching of metals, glasses and plastics, lateral etching is responsible for producing undercut. As a result, high depth to width ratio profiles of etched slots cannot be obtained easily in thick materials. However, in certain single crystal/etchant combinations, the etchant will dissolve certain crystal planes in preference to others. This is known as an anisotropic etching system. By controlled anisotropic etching of (110) silicon, lateral etching can be greatly reduced. The resultant slots have straight, parallel edges with perpendicular sidewalls and high depth to width ratio profiles.