JPS6461641A - Semiconductor pressure sensor - Google Patents

Abstract

PURPOSE:To measure both absolute pressure and relative pressure at the same time by applying an equal pressure to one-side parts of two pressure sensing diaphragms and applying a fluid pressure to the other side of one diaphragm. CONSTITUTION:The two pressure sensing diaphragms 16 and 17 are formed on a semiconductor single crystal chip 15 and the diaphragm 16 is opened to a pressure connecting pipe 3 through a support wafer 13 and through-holes 14, 11, and 7 formed in the pedestal 9. Then a vacuum chamber 18 is formed between the diaphragm 17 and support wafer 13, the equal pressure is applied to one-side surfaces of the diaphragms 16 and 17, and the fluid pressure is applied to the other surface of the diaphragm 16. Consequently, the absolute value and relative value of object pressure are measured at the same time.