Patent ID: 8272256

Claim:
A pressure sensor comprising: a Si device for detecting a pressure P, which is an object of detection, through detection of a stress occurring to the Si device itself by the pressure P, the Si device formed from a plate-shaped SOI substrate and having (a) a first main surface that has a bonded area, (b) a second main surface that is parallel to the first main surface, (c) a pressure-sensitive resistor which is formed on the first main surface and whose resistance changes according to the pressure P, and (d) a joining assist pattern that is formed on the first main surface, and a pressing member bonded to the bonded area on the first main surface of the Si device through anodic bonding, and compressing the Si device in a thickness direction of the Si device by pressing the bonded area by a pressing force according to the pressure P, and the pressure-sensitive resistor having a first bonded section which is placed within the bonded area of the first main surface and is bonded to the pressing member, and the joining assist pattern having a second bonded section which is made of the same material as the first bonded section of the pressure-sensitive resistor and is placed within the bonded area of the first main surface and is bonded to the pressing member.