| 摘要 |
PURPOSE:To contrive reduction of the etching time and improvement in the detection sensitivity and reduction of stray capacity by a composition wherein an area of an electrode part composing a measurement capacitance together with a diaphragm part is at least smaller than the diaphragm part and it is supported by plural arms. CONSTITUTION:Etching of an insulating layer 2 is performed by using an opening 3 of a metallic layer as a mask. At this time, an insulating layer 9 on the side where a metal is not attached is also formed an opening so as to form a perfect-square diaphragm part and etching is done. After that, the metal is left in a manner the perfect square thus formed has arms 14 and the metal of other part is removed by etching. When etching proceeds, the part under the internal square is hollowed out and becomes a cavity 12. Meanwhile, the opposite side to this cavity is etched similarly to form a recess surrounded by four (111) planes and a thin part becomes a diaphragm 11. The ratio gamma(=ae/a) of lengths of the sides of the internal and external squares which are formed by a metallic layer (an electrode part) 1 and the diaphragm 11 is so selected that it is smaller than 1.
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