Pressure sensor having semiconductor diaphragm

摘要

A pressure sensor of the type having a semiconductor diaphragm such as a silicon diaphragm which is formed with at least one diffused resistor in a surface region on one side thereof. A silicon block having the diaphragm is bonded to the inside of a box-like package such that the diffused resistor is exposed in a vacuum chamber defined in the package and that a fluid pressure can arrive at the back side of the diaphragm through a hole of the package. To minimize unwanted straining of the silicon diaphragm by thermal influences, the package is made of a material such as mullite whose linear expansion coefficient is close to that of silicon. To prevent an accidental change in the output characteristic of the sensor by the influence of an unintended external force, the package is supported above a base plate by pillar-like lead frames and confined in a space provided by fixing a cap to the base plate. A pressure introduction pipe is attached to either the base plate or the cap.