Pressure sensor using resin adhesive between sensor element and stem

• US 6,595,067 B2
• Filed: 03/07/2002
• Issued: 07/22/2003
• Est. Priority Date: 04/11/2001
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Suzuki, Yasutoshi, Tanaka, Hiroaki
• Primary Examiner(s): Noori, Max
• Assistant Examiner(s): ELLINGTON, ALANDRA
• Application Number:
  US10/091,476
• Publication Number:
  US 20020148297A1
• Time in Patent Office: 502 Days
• Field of Search: 737/54, 737/08, 737/21, 737/56, 737/27, 731/465, 737/00, 737/53, 737/15--28, 738/626.8
• US Class Current: 73/754
• CPC Class Codes: G01L 19/147 Details about the mounting of the sensor to support or covering means
• CPC Class Codes: G01L 9/0042 Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively
• CPC Class Codes: G01L 9/0055 bonded on a diaphragm

Abstract

In a pressure sensor made by bonding a sensor chip and a metal stem together with a resin adhesive, fluctuation of the sensor output caused by temperature changes are maximally reduced. The resin adhesive for bonding together the sensor element and the metal stem has a creep characteristic defined as CR=A×σ^B between its creep rate CR and stress σ upon it with A and B being constants. The resin adhesive is selected to satisfy that the constant B is not greater than 3.5.

Claims

1. A pressure sensor comprising:

a sensor element for outputting a signal corresponding to an applied pressure;

a stem bonded to the sensor element and supporting the sensor element; and

a resin adhesive bonding the sensor element and the stem,

wherein the resin adhesive has a creep characteristic such that, when its creep rate is defined as CR and its stress is defined as σ

, its creep rate CR is given as CR=A×

σ

^B with A and B being constants, and

wherein the constant B is not greater than 3.5.

2. A pressure sensor according to claim 1, wherein the constant B is not greater than 3.

3. A pressure sensor according to claim 1, wherein the resin adhesive comprises imide resin.

4. A pressure sensor according to claim 1, wherein the sensor element includes piezo-resistors integrated with a circuit part for processing the signal from the piezo-resistors.

5. A pressure sensor according to claim 4, wherein the circuit part includes at least one of a MOS transistor element and a bipolar transistor.

6. A pressure sensor according to claim 4, wherein the circuit part is for amplifying and for adjusting the signal from the piezo-resistors, and for outputting the signal from the piezo-resistors as a sensor output via interconnection members.

7. A pressure sensor comprising:

a sensor element for outputting a signal corresponding to an applied pressure and comprised entirely of discrete components;

a stem bonded to the sensor element and for supporting the sensor element; and

a resin adhesive having a bonding temperature lower than that of a glass resin for bonding the sensor element and the stem,

wherein the resin adhesive has a creep characteristic such that, when its creep rate is defined as CR and its creep stress is defined as a, its creep rate CR is given as CR=A×

σ

^B with A and B being constants and B not being greater than 3.5 to reduce fluctuation caused by the creep stress in the signal output by the sensor element.

8. The pressure sensor of claim 7, wherein the sensor element comprises an automotive fuel injection pressure sensor element.

9. The pressure sensor of claim 7, wherein 0<

B≦

3.0.

10. The pressure sensor of claim 7, wherein the resin adhesive comprises an imide resin adhesive.