Thermal membrane sensor and method for the production thereof

US6825057B1 · kind B1 · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Klaus Heyers · Reutlingen, DE
• Wilhelm Frey · Palo Alto, US

Key dates

• Filing date: Oct 25, 1999
• Grant date: Nov 30, 2004
• Expiry date: Oct 25, 2019

Classification

• Technology area (CPC G): Physics
• CPC primary: G01K7/028
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A process for manufacturing a membrane sensor over a silicon substrate, preferably a thermal membrane sensor. A thin layer of silicon carbide or silicon nitride is deposited over an area of porous silicon formed in the surface of the substrate, and then openings that extend as far as the layer of porous silicon are formed in the silicon carbide or silicon nitride layer via a dry etching process. Next, semiconductor structures and conductor path structures are implanted into the upper surface of the membrane layer via lithographic steps, and then the sacrificial layer of porous silicon is removed using a suitable solvent such as ammonia. Thus an empty space that thermally isolates the sensor membrane from the substrate is created beneath the membrane layer.