Patent ID: 6156585
Filing Date: 2000-12-05
Classification: G01L

Abstract:
A method of manufacturing a differential capacitor pressure sensor comprising:providing a semiconductor substrate having first and second surfaces opposite each other;depositing a layer of a semiconductor material in physical contact with the second surface of the semiconductor substrate;forming a first movable diaphragm layer on the second surface of the semiconductor substrate wherein the first movable diaphragm layer forms a first electrode of the differential capacitor pressure sensor;forming a fixed electrode layer having a first portion on the second surface of the semiconductor substrate and a second portion overlying the first movable diaphragm layer wherein the first fixed electrode layer forms a second electrode of the differential capacitor pressure sensor;forming an isolation layer on the first portion of the fixed electrode layer;forming a top movable diaphragm layer having a first portion on the isolation layer and a second portion overlying the second portion of the second portion of the fixed electrode layer wherein the top movable diaphragm layer forms a third electrode of the differential capacitor pressure sensor; andusing an etchant to anisotropically etch a hole from the first surface of the semiconductor substrate through the semiconductor substrate, to isotropically etch the layer, and to anisotropically etch the second surface of the semiconductor substrate wherein the hole at the first and second surfaces of the semiconductor substrate is larger than the hole at an inner portion of the semiconductor substrate and wherein the etchant is supplied to the second surface of the semiconductor substrate only from the hole in the semiconductor substrate.