Patent ID: 7762141

Claim:
A pressure sensor for detecting pressure of a pressure medium comprising: a sensor chip including a semiconductor substrate, a first diaphragm and a gauge resistor, wherein the semiconductor substrate has first and second sides, wherein the semiconductor substrate further includes a first concavity on the second side and a hole disposed on the second side, wherein the first concavity provides a thin portion as the first diaphragm, and wherein the gauge resistor) is disposed on the first diaphragm; a protection cap covering the first diaphragm and bonded to the first side of the semiconductor substrate; a case including a hollow portion for accommodating the sensor chip with the protection cap and a mounting surface for mounting the sensor chip, wherein the case introduces the pressure medium to a pressure receiving surface of the protection cap, and introduces atmospheric air to the second side of the semiconductor substrate; a terminal electrically coupling between the sensor chip and an external circuit; a wiring electrically coupling between the gauge resistor and the terminal; and a seal member having a ring shape, wherein when the protection cap is distorted according to the pressure of the pressure medium introduced to the pressure receiving surface, a force corresponding to distortion of the protection cap transmits from the protection cap to the first diaphragm, a resistance of the gauge resistor is changed, and a detection signal corresponding to a resistance change is output through the wiring and the terminal to the external circuit, the wiring includes an embedded portion and a connection portion, the embedded portion is embedded in the hole of the semiconductor substrate through an inner wall insulation film so that the embedded portion is insulated from the semiconductor substrate with the inner wall insulation film, and electrically coupled with the gauge resistor, the connection portion is disposed between a part of the embedded portion and a part of the terminal so that the connection portion electrically couples between the embedded portion and the terminal, the part of the embedded portion exposed from the second surface of the semiconductor substrate and the part of the terminal exposed from the mounting surface of the case, the embedded portion is covered with the protection cap so that the embedded portion is isolated from the pressure medium, the seal member is disposed between the mounting surface of the case and the second side of the semiconductor substrate, the hollow portion includes a first hollow portion and a second hollow portion, the pressure medium is introduced into the first hollow portion, and the atmospheric air is introduced into the second hollow portion, the seal member separates the first hollow portion from the second hollow portion so that pressure difference between the first and second hollow portions is maintained, and the seal member isolates the connection portion from the pressure medium and the atmospheric air.