Semiconductor sensor and method of manufacturing the same

摘要

This invention provides a semiconductor sensor (21) whose diaphragm (25) is resistant to breakage and in which variations in sensor sensitivity are small. A recess (26) is formed in a bottom surface of an SOI substrate obtained by bonding a Si substrate (22) and a Si thin film (24) with a SiO 2 film (23) interposed therebetween. Part of the Si thin film (24) constitutes the diaphragm (25) functioning as a sensitive region. In a top outer circumference of the recess (26), the SiO 2 film (23) covers a bottom outer circumference of the diaphragm (25) such that a bottom surface of the diaphragm (25) is exposed in its region except the outer circumference at a top surface of the recess (26). The SiO 2 film (23) (reinforcement (23a) covering the bottom outer circumference of the diaphragm (25) tapers off at its bottom surface such that the film thickness gradually decreases from a side of the outer circumference of the diaphragm (25) toward the center of the diaphragm (25).