Patent ID: 6460234
Filing Date: 2002-10-08
Classification: G01L,Y10T

Abstract:
A method of forming a micromachined pressure sensor comprising:(a) lithographically masking a semiconductor substrate and etching away the semiconductor substrate forming a relatively thin walled base structure surrounding an open-ended cavity having a single open end; (b) masking regions of the semiconductor substrate which are not adjacent to, inside, or underneath the base structure forming masked regions of the semiconductor substrate, not masking regions of the semiconductor substrate which are adjacent to, inside, or underneath the base structure forming unmasked regions of the semiconductor substrate; (c) diffusing a dopant into the base structure and to a selected depth into the unmasked regions of the semiconductor substrate in a region around the base structure which extends outwardly therefrom forming doped portions of the semiconductor substrate in the unmasked regions of the semiconductor substrate and forming undoped portions of the semiconductor substrate in the masked regions of the semiconductor substrate; (d) bonding the base structure to a structural substrate to form a sealed cavity comprised of the structural substrate, the base structure and the doped portions of the semiconductor substrate; and (e) etching away the undoped portions of the semiconductor substrate to leave a diaphragm with an outwardly extending skirt that is comprised of the doped portions of the semiconductor substrate and that is integrally attached to the base structure.