MONOLITHIC MICROBRIDGES IN SILICON USING LASER MACHINING AND ANISOTROPIC ETCHING

Microbridges in silicon can be used as resonating elements for the rea lization of mechanical sensors. A method for the fabrication of monoli thic microbridges in silicon with triangular cross sections and a thic kness up to 200 mum is presented. This method combines laser machining with wet anisotropic etching. The principle of this technique is base d on the local destruction of limiting {111} crystal planes by laser m elting and anisotropic etching of the molten zones. The geometry of th e microbridges produced by this method in [110] silicon wafers is dete rmined by the parameters of the masking layer and the laser beam. Fini te element analysis is used to estimate the static and dynamic behavio r of the triangular microbridges with regard to their application as r esonators of micromechanical force or pressure sensors. The results of analytical and numerical calculations were experimentally verified by means of laser Doppler technique.