Semiconductor pressure sensor with casing and method for its manufacture

• US 4,823,605 A
• Filed: 02/02/1988
• Issued: 04/25/1989
• Est. Priority Date: 03/18/1987
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Stein, Karl-Ulrich
• Primary Examiner(s): WOODIEL, DONALD
• Application Number:
  US07/151,371
• Time in Patent Office: 448 Days
• Field of Search: 73/727, 73/721, 73/DIG. 4, 73/706, 29/610 SG, 338/4, 338/42, 128/675, 128/748
• US Class Current: 73/727
• CPC Class Codes: G01L 19/147 Details about the mounting of the sensor to support or covering means
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/10253 Silicon [Si]
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/1815 Shape
• CPC Class Codes: Y10T 29/49103 Strain gauge making

Abstract

A semiconductor pressure sensor and method for its manufacture. Preferably, the pressure sensor is used as an absolute pressure sensor. The pressure sensor includes a pressure sensor chip of semiconductor material, the pressure sensor chip including a piezoresistive diaphragm. The pressure sensor is arranged in a casing which has an aperture for transmitting the ambient pressure to the diaphragm of the pressure sensor chip. The pressure sensor chip is fastened on a conductive tape and the conductive tape is a component of the casing. The casing consists of a hard synthetic material and contains the pressure sensor chip. The casing is configured so that the method of manufacture and tooling for manufacture allow cost-efficient production. The casing also offers protection for the pressure sensor during testing, equipping and during application in a circuit. The pressure sensor also includes a soft elastic material for covering the pressure sensor chip and transmitting ambient pressure from the aperature to the diaphragm.

Claims

1. A pressure sensor comprising:

a pressure sensor chip of semiconductor material fastened on a conductor tape, the chip including a piezoresistive diaphragm;

a casing for containing the pressure sensor chip and piezoresistive diaphragm, the casing defining an aperture for allowing the ambient pressure to communicate with the diaphragm of the pressure sensor chip, the conductor tape being a component of the casing; and

an elastic material for covering a portion of the diaphragm and transmitting pressure to the diaphragm.

2. The pressure sensor of claim 1, wherein the pressure sensor chip consists of silicon and the diaphragm is ion implanted.

3. The pressure sensor of claim 2, wherein the elastic material is a silicon gel.

4. The pressure sensor of claim 3, wherein the casing is fabricatd from a duroplastic material.

5. The pressure sensor of claim 3, wherein the pressure sensor chip and diaphragm cooperate to form an evacuated void.

6. A method for manufacturing a pressure sensor comprising the steps of:

bonding a pressure sensor chip including a diaphragm to a conductor tape;

covering the pressure sensor chip with an elastic material; and

coating the elastic material with a duroplastic to form a casing having an aperture, the aperture allowing the diaphragm to communicate with the ambient pressure.