Mario Danilo Velez

US Patent:

54542707, Oct 3, 1995

Filed:

Jun 6, 1994

Appl. No.:

8/254849

Inventors:

Clem H. Brown - Scottsdale AZ
Daniel J. Wallace - Phoenix AZ
Mario F. Velez - Phoenix AZ

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

G01L 708

US Classification:

73720

Abstract:

A differential pressure sensor (10) has a sensor die (16) attached to a stress isolation package base (12) with a bonding glass (27) having a similar coefficient of thermal expansion. The bonding glass, and alternately an aluminum layer, provides a hermetic seal between the stress isolation base and sensor die. Pressure is applied to the sensor die port (24). A plastic housing (14) is attached to the stress isolation base with an adhesive (29). A port (23) in the plastic housing is filled with a silicone gel (22). A second pressure source is transferred by way of the silicone gel to the sensor die. Any hostile chemical entering the via contacts the first surface of the sensor die to assert pressure against a transducer circuit (25) to generate the electrical signals representative of the applied pressure but are isolated from the sensitive interconnects by the hermetic seal.