Optimization of Concentration and Temperature of KOH Etchant on Micromachining Process

Abstract

Due to vast application of silicon wet etching in Micromachining and MEMS structure, investigation about parameters that have more influence on wet etch rate is indispensable. Wet etch rate is dependent to several factor such as temperature, etchant concentration and crystal orientation. Because of temperature and concentration are more controllable therefore the etch rates R{hkl} depend mainly on concentration and temperature of the etchant. Understanding the relation between this parameters and wet etch rate can assist us in order to control and optimization of micromachining process. This paper present a relation between etchant concentration and temperature and wet etch rate on (100) plane, and then identify the etchant concentration in a certain range of temperature as the wet etch rate be in optimal amount. With optimization the etch rate of wafer (100), necessary time for etching process reduces and this reduction of time can lead to reduction of undercutting at convex and concave corners.