Semiconductor absolute pressure transducer assembly and method

Abstract

A semiconductor pressure transducer assembly comprising a silicon diaphragm assembly and a glass covering member. The silicon diaphragm assembly has a circular diaphragm portion of thin silicon which is formed using etching, and a thick supporting portion therearound. Piezoresistive elements of a piezoresistive bridge circuit and conducting paths for electrically connection thereof are formed on the silicon diaphragm assembly. On a surface of the silicon diaphragm assembly, a passivating layer of silicon dioxide are formed in uniform thickness, and further on a surface of the passivating layer is formed a layer of polysilicon on the supporting portion of the silicon diaphragm assembly. In the passivating layer, a contacting window is formed, through which the polysilicon layer is electrically connected to the silicon diaphragm assembly. The covering member of borosilicate glass having a circular well is mounted and bonded onto the silicon diaphragm assembly in contact with the polysilicon layer using Anodic Bonding method. And the processed silicon diaphragm assembly has a flat surface thereof, on which the piezoresistive elements and the conducting paths are constructed using Ion Implantation method, or reforming a silicon dioxide layer thereon after removing another silicon dioxide layer used as mask in diffusing process.