| 摘要 |
PROBLEM TO BE SOLVED: To suppress an influence of a movable ion to offset a voltage without destabilizing stress balance on the surface of a diaphragm. SOLUTION: A conductive thin film 7 is formed line-symmetrically with respect to the center axis of the diaphragm 2 on the surface of an insulating film 6 corresponding to the surface of the diaphragm 2 and surfaces of piezo-resistive elements R1, R2, R3 and R4. This conductive thin film 6 functions as a shield layer for suppressing variations of resistances of piezo-resistive elements R1, R2, R3 and R4 by the movable ion existing on the surface of the semiconductor pressure sensor 1 when a power supply is turned on, so that it can suppress a variation of an offset voltage of a bridge circuit when the power supply is turned on. The conductive thin film 7 is formed on the whole surface of the diaphragm 2 and has a line-symmetric shape with respect to the center axis of the diaphragm 2, so that the stress balance on the surface of the diaphragm section 2 is made to be favorable and the generation of the offset voltage can be suppressed compared with the case that the conductive thin film 7 is formed non-locally in an asymmetric shape. COPYRIGHT: (C)2009,JPO&INPIT
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