Semiconductor sensor for detecting physical amount without thermal hypsteresis where output wiring is disposed in a stress insensitive direction

• US 5,537,882 A
• Filed: 10/03/1994
• Issued: 07/23/1996
• Est. Priority Date: 10/05/1993
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Murakami, Susumu, Ugai, Seiichi, Takahashi, Yukio, Maruyama, Yasuo, Yamamoto, Yoshimi, Shimada, Satoshi
• Primary Examiner(s): Chilcot, Richard
• Assistant Examiner(s): FELBER, JOSEPH LEON
• Application Number:
  US08/317,156
• Time in Patent Office: 659 Days
• Field of Search: 73/517 R, 73/708, 73/721, 73/727, 324/71.5, 338/2-5, 338/42
• US Class Current: 73/727
• CPC Class Codes: G01L 9/0054 integral with a semiconducting diaphragm
• CPC Class Codes: G01P 1/006 used for thermal compensation
• CPC Class Codes: G01P 15/123 by piezo-resistive elements, e.g. semiconductor strain gauges

Abstract

A sensor for detecting physical amount in which a gauge resistance value is made not to change even when a wiring material presents a yield phenomenon by wiring a wiring material Such as aluminum presenting a yield phenomenon by thermal stress in a stress insensitive direction of a piezogauge.

Claims

1. A sensor for detecting a physical amount comprising:

at least one resistor formed on a semiconductor substrate; and

an output wiring connected to said at least one resistor and disposed in a stress insensitive direction of said semiconductor substrate whereby a resistance state of said at least one resistor is ascertainable via said output wiring.

2. A sensor for detecting physical amount according to claim 1, further comprising an output terminal provided on said semiconductor substrate and connected to said output wiring.

3. A sensor for detecting physical amount according to claim 1, wherein two or more of said resistors are provided on said semiconductor substrate, and said output wiring combines said two or more of said resistors.

4. A sensor for detecting physical amount according to claim 3, wherein a Wheatstone bridge is formed of said two or more of resistors.

5. A sensor for detecting physical amount according to claim 1, wherein said resistor detects a differential pressure state.

6. A sensor for detecting physical amount according to claim 1, wherein said resistor detects a static pressure state.

7. A sensor for detecting physical amount according to claim 1, wherein said resistor detects an acceleration state.

8. A sensor for detecting physical amount according to claim 1, wherein said resistor detects a temperature state.

9. A sensor for detecting a physical amount comprising:

at least one resistor formed on a semiconductor substrate; and

an output wiring connected to said at least one resistor and disposed in a stress insensitive direction of said semiconductor substrate whereby a resistance state of said at least one resistor is ascertainable via said output wiring; and

wherein said semiconductor substrate comprises a {011} plane silicon substrate, said at least one resistor comprises a piezogauge resistance arranged in a <

110>

direction on said semiconductor substrate, and said output wiring is provided in a <

100>

direction.

10. A sensor for detecting a physical amount comprising:

at least one resistor formed on a semiconductor substrate; and

an output wiring connected to said at least one resistor and disposed in a stress insensitive direction of said semiconductor substrate whereby a resistance state of said at least one resistor is ascertainable via said output wiring; and

wherein said semiconductor substrate comprises a {011} plane silicon substrate, said at least one resistor comprises a piezogauge resistance arranged in a <

110>

direction on said semiconductor substrate, and said output wiring is provided in a <

100>

direction.

11. A sensor for detecting a physical amount comprising:

a piezogauge resistor formed on a semiconductor substrate;

a shielding low resistance member composed of aluminum 5 to 30 nm in thickness provided so as to cover said piezogauge resistor; and

a resistance state output coupled to said piezogauge resistor.

12. A sensor for detecting physical amount according to claim 11, wherein an n-type silicon substrate is used as said semiconductor substrate, and a p-type resistor is used as said piezogauge resistor.

13. A sensor for detecting physical amount according to claim 12, wherein a diaphragm is formed in said semiconductor substrate, said resistor is provided in the neighborhood of a thin wall portion of said diaphragm, a contact portion between said shielding low resistance material and said semiconductor substrate is provided in a thick wall portion of said semiconductor substrate and said shielding low resistance material is made to show a potential equal to the potential of said semiconductor substrate.

14. A sensor for detecting physical amount according to claim 13, wherein a connecting direction of said shielding low resistance material to said contact portion is provided in a stress insensitive direction of said semiconductor substrate.

15. A sensor for detecting physical amount according to claim 14, wherein a {001} plane silicon substrate is used as said semiconductor substrate, and a connecting direction of said low resistance material to said contact portion is provided in a <

100>

direction.

16. A sensor for detecting a physical amount comprising:

a semiconductor substrate in which a direction of dicing the semiconductor substrate is set to a stress insensitive direction of said semiconductor substrate;

a resistor formed on said semiconductor substrate; and

an output wiring provided in a stress insensitive direction of said semiconductor substrate outputting a resistance state of said resistor;

wherein said semiconductor substrate comprises a {001} plane silicon substrate, said resistor comprises a piezogauge resistance arranged in a <

110>

direction on said semiconductor substrate, a wiring for outputting a resistance state of said piezogauge resistance is provided in a <

100>

direction, and said dicing direction is set to the <

100>

direction.

17. A sensor for detecting physical amount comprising:

a piezogauge resistor formed on a semiconductor substrate; and

means for outputting a resistance state of said piezogauge resistor;

wherein;

a low resistance material that satisfies the following expression;

space="preserve" listing-type="equation">σ

.sub.y ≧

|E.sub.m (α

.sub.m -α

.sub.SiO2)Δ

t|

when it is assumed that σ

_y represents yield stress of a wiring material for outputting a resistance state of said resistor or a shield material for shielding the resistance, α

_m the coefficient of thermal expansion thereof, α

_SiO2 the coefficient of thermal expansion of the foundation SiO₂ of the wiring material and the shield material, Δ

t a difference between the upper limit and the lower limit of the temperature applied to the sensor, and E_m Young'"'"'s moduli of the wiring material and the shield material, is used for said wiring material and said shield material.

18. A sensor for detecting physical amount according to claim 17, wherein the shield material is composed of Ti, W, Mo or polysilicon.