MICROMACHINING METHOD FOR FABRICATING ULTRAMICRO DEVICE TO SEPARATELY FABRICATE THIN P LAYER AND MASS HAVING WHOLE THICKNESS OF SILICON

摘要

PURPOSE: A micromachining method for fabricating an ultramicro device is provided to separately fabricate a thin p¬+ layer and a mass having the whole thickness of silicon by controlling the ratio of a thickness of a beam to a thickness of the mass. CONSTITUTION: P¬+ diffusion layers(2,3) are formed on both surfaces of a single crystalline silicon substrate(1). After a mask corresponding to the width of a beam and a mass is formed on one of the p¬+ diffusion layer, the mask is etched by an isotropic etching method to penetrate the p¬+ diffusion layer and the single crystalline silicon. By using an etchant for stopping an etch process before the p¬+ diffusion layer, the single crystalline silicon between the beams is completely etched to fabricate a beam made of the p¬+ diffusion layer. After the single crystalline silicon of the mass is etched in a predetermined direction, the etch process is stopped to fabricate the mass.