Semiconductor pressure sensor for e.g., as intake pressure sensor in vehicle engine intake, has semiconductor substrate, diaphragm portion, strain gauge, circuit portion, and local oxidation of silicon film

摘要

A semiconductor pressure sensor comprises a semiconductor substrate; a diaphragm portion formed as a bottom of a recess portion; a strain gauge for generating an electric signal; a circuit portion for detecting the electric signal from the strain gauge; and a local oxidation of silicon film formed on a main surface of a first silicon substrate opposite to a second silicon substrate. A semiconductor pressure sensor comprises a semiconductor substrate (10) including a first silicon substrate (11), a second silicon substrate (12) having a recess portion (2), and an insulation film (13) between the first and second substrates; a diaphragm portion (1) formed by the first silicon substrate as a bottom of the recess portion to be deformed by a pressure; a strain gauge (3) formed on the diaphragm portion for generating an electric signal in accordance with deformation of the diaphragm portion; a circuit portion for detecting the electric signal from the strain gauge, formed on the first silicon substrate at a portion other than the diaphragm portion; and a local oxidation of silicon (LOCOS) film formed on a main surface of the first silicon substrate opposite to the second silicon substrate. The LOCOS film (15) is located outside an outermost peripheral portion (G) of a thin-wall portion of the diaphragm portion and electrically isolating the strain gauge from the circuit portion.