Controlled Release of Microcantilever from a Silicon-on-Insulator Wafer with Oxide Brace

Abstract

This paper discussed a releasing process of microcantilever from silicon-on-insulator (SOI) wafer by a wet etching method, which is popular in semiconductor technology. A brace oxide in the cantilever was applied to prevent the beam from bending upwards during releasing process. The planar molybdenum (Mo) mask obtained by the etch-back process covered the cantilever structure with a Mo resistor from tetramethylammonium hydroxide (TMAH) etchant. As a result, the microcantilever structure with a Mo resistor could be released without crack and kept maintaining the Mo resistor’s electrical stability. These results open up the possibility of utilizing the BOX brace combined with the planar Mo layer to prevent damages in the cantilever during fabrication with anisotropic silicon etching using TMAH.