A Novel Method for Determining theEtch Rate Distributions of Si
测定硅各向异性腐蚀速率分布的新方法

A novel method for measuring the anisotropic etch rate distributions of Si is described. A three\|dimensional anisotropic etch rate distribution of Si can be described by two\|dimensional etch rate distributions in a series of crystal planes. Deep reactive ion etching (DRIE) is used for creating rectangular trenches whose sidewalls are perpendicular to the wafer surface in {0 mn } wafers. By measuring the width of the trenches before and after anisotropic etching, two\|dimensional distributions in { 0mn} wafers can be determined. With the two\|dimensional distributions, the three\|dimensional distributions can be determined. As the height of the vertical side walls made by DRIE is high enough to withstand reasonable long time etching, a conventional microscope is accurate enough. Etch rate distributions of { n 10} and {\%n11}\% crystal planes in 40% KOH and 25% TMAH are presented.