Pressure sensor having semiconductor sensor chip

• US 6,694,818 B2
• Filed: 07/16/2001
• Issued: 02/24/2004
• Est. Priority Date: 08/25/2000
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kuroda, Michitake, Chikuan, Kenji
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): ELLINGTON, ALANDRA
• Application Number:
  US09/904,898
• Publication Number:
  US 20020023500A1
• Time in Patent Office: 953 Days
• Field of Search: 737/15, 732/61, 737/20, 437/209
• US Class Current: 73/715
• CPC Class Codes: G01L 19/0084 to the outside of the housing other details about the housing see G01L19/14
• CPC Class Codes: G01L 19/0645 using isolation membranes, specially adapted for protection
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/15151 the die mounting substrate comprising an aperture, e.g. for underfilling, outgassing, window type wire connections

Abstract

A semiconductor sensor chip is interposed between a sensor case and a housing. A first pressure is introduced from the sensor case and applied to a rear surface of the sensor chip, while a second pressure is introduced from the housing and applied to a front surface of the sensor chip. The sensor chip detects a pressure difference between the first and the second pressures and converts it into an electrical signal. The sensor chip is hermetically mounted in a depressed portion formed in the sensor case by charging a sealing material from holes formed around the depressed portion. The charging holes are positioned between terminals electrically connecting the sensor chip to an outside circuit to avoid enlarging the pressure sensor size by forming the charging holes.

Claims

1. A pressure sensor comprising:

a cylindrical sensor case having a depressed portion formed at one longitudinal end, the depressed portion communicating wit a first pressure source through a through-hole formed in the sensor case;

a sensor chip having a front surface and a rear surface, the sensor chip being mounted in the depressed portion so that the rear surface receives the first pressure supplied from the first pressure source;

oil disposed in the depressed portion to cover the front surface of the sensor chip;

a plurality of terminals disposed around the depressed portion for electrically connecting the sensor chip to an outside circuit;

means for supplying a second pressure from a second pressure source to the oil covering the front surface of the sensor chip, the second pressure being imposed on the front surface of the sensor chip through the oil so that the sensor chip detects a pressure difference between the first and the second pressures;

a sealing material composed of resin charged in the depressed portion to prevent the first pressure from communicating with the second pressure; and

a plurality of charging holes for charging the sealing material into the depressed portion, each charging hole being formed between the neighboring two terminals.

2. A pressure sensor comprising:

a cylindrical sensor case having a depressed portion formed at one longitudinal end, the depressed portion communicating with a first pressure source through a through-hole formed in the sensor case;

a sensor chip having a front surface and a rear surface, the sensor chip being mounted in the depressed portion so that the rear surface receives the first pressure supplied from the first pressure source;

oil disposed in the depressed portion to cover the front surface of the sensor chip;

a plurality of terminals disposed around the depressed portion for electrically connecting the sensor chip to an outside circuit;

means for supplying a second pressure from a second pressure source to the oil covering the front surface of the sensor chip, the second pressure being imposed on the front surface of the sensor chin through the oil so that the sensor chip detects a pressure difference between the first and the second pressures;

a sealing material composed of resin charged in the depressed portion to prevent the first pressure from communicating with the second pressure; and

a plurality of charging holes for charging the sealing material into the depressed portion, each charging hole being formed between the neighboring two terminals, wherein

the depressed portion and the sensor chip are rectangular-shaped in a plan view, and the sensor chip is positioned in the depressed portion so that sides of the sensor chip are in parallel with sides of the depressed portion; and

the charging holes are formed at four corners of the depressed portion.

3. The pressure sensor as in claim 2, wherein:

each of the plurality of charging holes includes a tapered slope that outwardly enlarges each of the plurality of charging holes in an opening direction thereof.

4. A pressure sensor comprising:

a cylindrical sensor case having a depressed portion formed at one longitudinal end, the depressed portion communicating with a first pressure source through a through-hole formed in the sensor case;

a sensor chip having a front surface and a rear surface, the sensor chip being mounted in the depressed portion so that the rear surface receives the first pressure supplied from the first pressure source;

oil disposed in the depressed portion to cover the front surface of the sensor chip;

a plurality of terminals disposed around the depressed portion for electrically connecting the sensor chip to an outside circuit;

means for supplying a second pressure from a second pressure source to the oil covering the front surface of the sensor chip, the second pressure being imposed on the front surface of the sensor chip through the oil so that the sensor chip detects a pressure difference between the first and the second pressures;

a sealing material composed of resin charged in the depressed portion to prevent the first pressure from communicating with the second pressure; and

plurality of charging holes for charging the sealing material into the depressed portion, each charging hole being formed between the neighboring two terminals, wherein

the charging holes are formed around the depressed portion at four positions equally spaced.

5. The pressure sensor as in claim 4, wherein:

a seal diaphragm for confining the oil therein is disposed, so that the second pressure is supplied to the seal diaphragm and transferred to the oil; and

a step for preventing the sealing material from creeping up from the depressed portion toward the seal diaphragm is provided around each charging hole.

6. The pressure sensor of claim 4, wherein the sensor chip comprises a relative pressure sensor chip.

7. The pressure sensor as in claim 4, wherein:

each of the plurality of charging holes includes a tapered slope that outwardly enlarges each of the plurality of charging holes in an opening direction thereof.

8. The pressure sensor as in claim 7, wherein:

each of the plurality of charging holes further includes a straight portion that vertically stands up from an outer-most position of the tapered slope.

9. A pressure sensor comprising:

a cylindrical sensor case having a depressed portion formed at one longitudinal end, the depressed portion for receiving a first pressure through a through-hole formed in the sensor case;

a sensor chip having a front surface and a rear surface and being mounted in the depressed portion so that the rear surface receives the first pressure;

oil disposed in the depressed portion and covering the front surface of the sensor chip, the oil for receiving a second pressure and conveying the second pressure to the front surface of the sensor chip to enable the sensor chip to detect a pressure difference between the first and the second pressures;

a sealing material for providing a hermetic seal between the front and rear surfaces of the sensor chip; and

a plurality of charging holes fir facilitating placement of the hermetic seal between the front and rear surfaces of the sensor chip.

10. The pressure sensor of claim 9, wherein the sensor chip comprises a relative pressure sensor chip.

11. The pressure sensor of claim 9, further comprising a plurality of connecting terminals disposed around the depressed portion and in electrical contact with the sensor chip.

12. The pressure sensor of claim 11, wherein each of the plurality of charging holes is located between adjacent connecting terminals of the plurality of connecting terminals.