Capacitive pressure sensor and method of manufacturing same

US5001595A · kind A · utility

Inventors

• Gerhard Dittrich · Lörrach, DE
• Frank Hegner · Bad Kötzting, DE
• Thomas Klahn · Glückstadt, DE

Key dates

• Filing date: Mar 23, 1990
• Grant date: Mar 19, 1991
• Expiry date: Mar 23, 2010

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T29/435
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The capacitive pressure sensor (10) has two disks (11, 12) of alumina which are joined together around the periphery in a defined spaced relationship and parallel to each other, forming a chamber (14). At least one of the two disks (11) is designed as an elastic diaphragm. A pure nickel coating (16, 18) is applied to the surface of each disk by electroless deposition from an aqueous solution, and on the surfaces of the two disks facing each other, capacitor electrodes (17, 20, 21) are formed by patterning the nickel coating. The capacitor electrodes are connected to an electronic circuit disposed outside the chamber (14) by additional nickel coatings which are formed in plated-through holes (30, 31, 32) simultaneously with the deposition of the pure nickel coating.