Semiconductor pressure sensor

Claim 1

A semiconductor pressure sensor comprising: an outer package having a pressure introduction port for introducing a gas for making a pressure measurement and an atmospheric pressure introduction port for introducing gas at atmospheric pressure into the outer package; a ceramic substrate directly mounted to and within the outer package and including a passage aligned with the pressure introduction port; a glass mount disposed within the outer package on the ceramic substrate and including a passage aligned with the passage in the ceramic substrate and with the pressure introduction port; a pressure sensor chip having opposed front and rear surfaces including a gauge pressure sensor section producing an electrical signal indicative of the difference between the pressure in the gas introduction port and atmospheric pressure and an absolute pressure sensor section producing an electrical signal indicative of the difference between atmospheric pressure and a vacuum wherein the glass mount and the pressure sensor chip are anodically bonded together at the rear surface of the pressure sensor chip and mounted within the outer package, the absolute pressure sensor section including an evacuated space at the rear surface of the pressure sensor chip and the glass mount, the gauge pressure sensor communicating at the rear surface of the pressure sensor chip with the pressure introduction port through the passages in the ceramic substrate and glass mount, atmospheric pressure being admitted into the outer package by the atmospheric pressure introduction port reaching the front surface of the pressure sensor chip; an IC chip mounted on the ceramic substrate within the outer package and electrically connected to the gauge pressure sensor section and the absolute pressure sensor section for generating an electrical signal indicative of the absolute pressure in the gas introduction port; and electrical leads extending through the ceramic substrate and outside of the outer package electrically connected to the IC chip for conducting the electrical signal indicative of the absolute pressure of the gas in the gas introduction port.