To relax the stress at the time of static pressure change and at the time of temperature change, to decrease the amount of zero shift furthermore, and to perform highly accurate differential pressure measurement in high sensitivity by providing a round fixing part, whose diameter is equal to or smaller than the diameter of a sensor substrate, at a fixing member.
Four strain-sensitive gage elements 4 are arranged around a diaphragm 3 on the surface of a sensor substrate 1, and stress applied on the diaphragm 3 is sensed. The substrate 1 is strongly bonded to a supporting member 2 by anode bonding. A fixing part 9a, which is bonded through a bonding layer 8, is formed at a fixing member 9. The shape of the fixing part 9a is made to be a round shape, whose diameter is equal to or smaller than the diameter of the substrate 1. When the round shape is formed, the formation of the fixing member 9 becomes easy, processing property is improved and the processing degree in the fixing part 9a can be made uniform. Therefore, the dispersion of thermal expansion coefficients is not generated. At the central part of the fixing part 9a, a projection 9b, which is arranged inside a through hole 7 of the supporting member 2, is provided. The projection 9b determines the positions of the supporting member 2 and the fixing member 9 with the through hole 7 as the guide.
TAKAHASHI YUKIO
ISHIHARA TAMIO
HIDA TOMOYUKI
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