Patent ID: 6038928
Filing Date: 2000-03-21
Classification: G01L

Abstract:
A method of making a structure which is useful to form a pressure sensor, said method comprisinga) etching a first silicon substrate to form a cavity, wherein the cavity has walls and the cavity has an opening to at least one surface of the first silicon substrate;b) forming a composite structure by fusion bonding the first silicon substrate to a second silicon substrate so that a portion of the second silicon substrate covers said opening of the cavity of the first silicon substrate and performing said fusion bonding in an oxygenated environment, thereby forming a thin protective oxide film on the walls of the cavity and on said portion of the second silicon substrate;c) etching the composite structure to form a channel in the composite structure, which channel opens to a surface of the composite structure and which channel has, as a wall, the protective oxide film; andd) etching the protective oxide film which forms said wall of the channel to provide a passageway through the composite structure and into the cavity within the first silicon substrate.