Convex corner compensation for a compact seismic mass with high aspect ratio using anisotropic wet etching of (100) silicon

This paper reports a novel convex corner compensation design for a compact seismic mass of high aspect ratio using KOH etching of (100) silicon. Anisotropic wet etching is often applied to fabricate a seismic mass due to cost advantage. Dimension of the convex corner compensation pattern is in proportional to etching depth, which restrain the miniature of seismic mass and supporting beams. If the width of the seismic is too small, overlap of compensation pattern occurs to cause a compensation failure. This study presents a corner compensation for a mesa with high aspect ratio using <;100>; oriented compensating bands augmented with a mandatory separation and a <;110>;-oriented beam to the truncated <;100>; bands due to the overlap of adjacent compensation patterns. An empirical equation is presented from the simulation of anisotropic etching using Intellisuite. The design can produce a satisfactory wet etching mesa with the aspect ratio of 0.6, while a typical <;100>; oriented compensating bands can only applied to a mesa with a largest aspect ratio of 0.35. A mesa is etched using 30%, 80°C KOH to verify the design feasibility.