| 摘要 |
PURPOSE:To make it possible to set the thickness of a cantilever part highly accurately, by forming the cantilever part by electrolytic etching from the lower surface. CONSTITUTION:An N-type silicon substrate 15 is formed on the upper surface of a silicon substrate 14. Then, thermal oxide films 16a and 16b, which are to become masks in etching, are formed on the lower surface of the substrate 14 and on the upper surface of the substrate 15. Then, a hole part 17 for an upper gap is formed in the film 16a. Anisotropic etching of silicon is performed, and a gap is formed. At this time, the width of the hole part 17 is set so that the etching is stopped when the etching reaches the substrate 14. A metal film 18 is formed on the upper surface of an element and an electrode is obtained. The electrode is made to be a voltage-applying contact when electrolytic etching is performed. The parts for a hole part 19 for a cantilever and a hole part 20 for a lower gap in the film 16b are removed. Thereafter, electrolytic etching is performed from the rear surface of the element. Finally, the metal film, which is formed on the entire upper surface of the element is removed. The films 16a and 16b are removed. Thus a semiconductor acceleration sensor is formed.
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