| 摘要 |
PURPOSE:To obtain an acceleration sensor which is small in size, low in cost, and excellent in mass productivity, by mounting a distortion gauge element or piezo-electric element on a cantilever formed on a semiconductor base plate by using an anisotropic etching method. CONSTITUTION:An (N)-type silicon layer 1' is formed on a (P)-type silicon base plate 1 and an insulating film 2 is formed on the layer 1'. By selectively removing the insulating film 2 around a distortion gauge element 5 put on the insulating film 2, the (N)-type layer 1' is exposed. When the (N)-type layer 1' is subjected to an anisotropic etching by using the insulating film 2 as a mask, the layer 1' is corrode and removed from the exposed part and a recessed section 3 having a trapezoidal cross section is formed in accordance with the crystal orientation. By means of the recessed section 3, the silicon oxide film below the element 5 forms a cantilever 4 which is projected above the recessed section 3. When a weight or acceleration or both of them are applied to the cantilever 4 in the vertical direction, the cantilever 4 is bent in the vertical direction and, when receives bending distortion, the element 5 made of a metallic film produces changes in resistance value. When the changes in resistance value are calculated, the load or acceleration can be detected.
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