Mechanical-quantity measuring device

• US 8,695,433 B2
• Filed: 01/04/2013
• Issued: 04/15/2014
• Est. Priority Date: 03/29/2006
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Shimazu, Hiromi, Ohta, Hiroyuki, Tanno, Yohei
• Primary Examiner(s): Caputo, Lisa
• Assistant Examiner(s): ROY, PUNAM P
• Application Number:
  US13/734,326
• Publication Number:
  US 20130118268A1
• Time in Patent Office: 466 Days
• Field of Search: None
• US Class Current: 73/777
• CPC Class Codes: G01B 7/18 using change in resistance
• CPC Class Codes: G01L 1/18 using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
• CPC Class Codes: G01L 1/2293 of the semi-conductor type semi-conductor devices controllable by variations of applied mechanical force H01L29/84

Abstract

A mechanical-quantity measuring device capable of measuring a strain component in a specific direction with high precision is provided.

At least two or more pairs of bridge circuits are formed inside a semiconductor monocrystal substrate and a semiconductor chip, and one of these bridge circuits forms a n-type diffusion resistor in which a direction of a current flow and measuring variation of a resistor value are in parallel with a <100> direction of the semiconductor monocryastal silicon substrate, and an another bridge circuit is composed of combination of p-type diffusion resistors in parallel with a <110> direction.

Claims

1. A mechanical-quantity measuring device provided with a strain detection unit on a surface of a semiconductor substrate and attached to a measured object to measure a strain, comprising a first sensor and a second sensor in which a Wheatstone bridge is formed with a plurality of diffusion resistors, respectively;

wherein the diffusion resistors composing the first sensor have a mutual distance smaller than a length of the diffusion resistors in the longitudinal direction,

wherein the diffusion resistors composing the second sensor have a mutual distance smaller than the length of the diffusion resistors in the longitudinal direction, and

wherein a distance between the first sensor and the second sensor is smaller than the length of the diffusion resistors in the longitudinal direction.

2. A mechanical-quantity measuring device provided with a strain detection unit on a surface of a semiconductor substrate and attached to a measured object to measure a strain, comprising a first sensor and a second sensor in which a Wheatstone bridge is formed with a plurality of diffusion resistors, respectively;

wherein the first sensor comprises four pieces of p-type impurity diffusion resistors having their longitudinal directions in a <

110>

direction, and

wherein the second sensor comprises four pieces of n-type impurity diffusion resistors having their longitudinal directions in a <

100>

direction.

3. A mechanical-quantity measuring device provided with a strain detection unit on a surface of a semiconductor substrate and attached to a measured object to measure a strain, comprising a first sensor and a second sensor in which a Wheatstone bridge is formed with a plurality of diffusion resistors, respectively;

wherein the first sensor and the second sensor are formed on a {100} plane of the semiconductor substrate formed of monocrystalline silicon,

wherein the first sensor comprises a Wheatstone bridge comprising two pieces of p-type impurity diffusion resistors in which a current flows in a <

110>

direction, mutually provided in parallel and forming resistors of opposite sides of the Wheatstone bridge, and two pieces of p-type impurity diffusion resistors in which a current flows in a <

110>

direction that is orthogonal to the direction of the p-type impurity diffusion resistors, mutually provided in parallel and forming resistors of opposite sides of the Wheatstone bridge, and

wherein the second sensor comprises a Wheatstone bridge comprising two pieces of n-type diffusion resistors in which a current flows in a <

100>

direction, mutually provided in parallel and forming resistors of opposite sides of the Wheatstone bridge, and two pieces of n-type diffusion resistors in which a current flows in a <

100>

direction that is orthogonal to the direction of the n-type impurity diffusion resistors, mutually provided in parallel and forming resistors of opposite sides of the Wheatstone bridge.

5. The mechanical-quantity measuring device according to claim 3,

wherein a mutual distance of the four pieces of the p-type impurity diffusion resistors of the first sensor is smaller than a length of in a longitudinal direction the p-type impurity diffusion resistors,

wherein a mutual distance of the four pieces of n-type impurity diffusion resistors of the second sensor is smaller than a length in a longitudinal direction of the n-type impurity diffusion resistors, and

wherein a distance between the first sensor and the second sensor is smaller than the lengths in the longitudinal directions of the p-type and n-type impurity diffusion resistors.

6. The mechanical-quantity measuring device according to claim 3,

wherein the semiconductor substrate is a p-type semiconductor substrate, and

wherein a periphery of p-type diffusion resistors of the first sensor is provided with an n-type impurity diffusion layer surrounding the p-type diffusion resistors.

7. The mechanical-quantity measuring device according to claim 3,

wherein the semiconductor substrate is an n-type semiconductor substrate, and

wherein a periphery of n-type diffusion resistors of the second sensor is provided with a p-type impurity diffusion layer surrounding the n-type diffusion resistors.

8. A body of rotation provided with the mechanical-quantity measuring device according to claim 3,

wherein a direction of rotation axis of the body of rotation is coordinated with the <

100>

direction or the <

110>

direction on the semiconductor substrate surface.

4. A mechanical-quantity measuring device provided with a strain detection unit on a surface of a semiconductor substrate and attached to a measured object to measure a strain, comprising a first sensor and a second sensor in which a Wheatstone bridge is formed with a plurality of diffusion resistors, respectively;

wherein the first sensor and the second sensor are formed on a {100} plane of the semiconductor substrate formed of monocrystalline silicon,

wherein the first sensor comprises a Wheatstone bridge formed by connecting a first p-type impurity diffusion resistor in which a current flows in parallel with a [110] direction, a second p-type impurity diffusion resistor in which a current flows in parallel with a [−

110] direction, a third p-type impurity diffusion resistor in which a current flows in parallel with the [110] direction, and a fourth p-type impurity diffusion resistor in which a current flows in parallel with the [−

110] direction in this order, and

wherein the second sensor includes a Wheatstone bridge formed by connecting a first n-type impurity diffusion resistor in which a current flows in parallel with a [100] direction, a second n-type impurity diffusion resistor in which a current flows in parallel with a [010] direction, a third n-type impurity diffusion resistor in which a current flows in parallel with the [100] direction, and a fourth n-type impurity diffusion resistor in which a current flows in parallel with the [010] direction in this order.

9. A mechanical-quantity measuring device provided with a strain detection unit on a surface of a semiconductor substrate and attached to a measured object to measure a strain, comprising a first sensor and a second sensor in which a Wheatstone bridge is formed with a plurality of diffusion resistors, respectively, and further comprising a third sensor,

wherein the first sensor comprises two pieces of n-type impurity diffusion resistors in which a current flows in a <

100>

direction, mutually provided in parallel and forming resistors of opposite sides of the Wheatstone bridge and two pieces of p-type impurity diffusion resistors in which a current flows in the <

100>

direction, forming resistors of the Wheatstone bridge,

wherein the second sensor comprises two pieces of n-type impurity diffusion resistors in which a current flows in a <

100>

direction that is orthogonal to the n-type impurity diffusion resistor of the first sensor, mutually provided in parallel and forming resistors of opposite sides of the Wheatstone bridge and two pieces of p-type impurity diffusion resistors in which a current flows in the <

100>

direction, forming resistors of opposite sides of the Wheatstone bridge, and

wherein the third sensor comprises four pieces of p-type impurity diffusion resistors in which a current flows in a <

110>

direction, forming resistors of a Wheatstone bridge.

10. The mechanical-quantity measuring device according to claim 9,

wherein the two pieces of n-type impurity diffusion resistors and the two pieces of p-type impurity diffusion resistors of the first sensor have their longitudinal directions being mutually in parallel and are arranged side by side in the <

110>

direction,

wherein the two pieces of n-type impurity diffusion resistors and the two pieces of the p-type impurity diffusion resistors of the second sensor have their longitudinal directions being orthogonal to the longitudinal directions of the n-type and p-type impurity diffusion resistors of the first sensor and are arranged side by side in the same direction with the <

110>

direction, and

wherein the four pieces of the p-type diffusion resistors of the third sensor are provided in an area on the <

100>

direction side of the first sensor and in an area on the <

100>

direction side of the second sensor.

11. A mechanical-quantity measuring device provided with a strain detection unit on a surface of a semiconductor substrate and attached to a measured object to measure a strain, comprising a first sensor and a second sensor in which a Wheatstone bridge is formed with a plurality of diffusion resistors, respectively;

wherein the second sensor is a sensor detecting a peeling off of the semiconductor substrate.

12. The mechanical-quantity measuring device according to claim 11,

wherein, in the second sensor, resistive elements forming a bridge circuit for a peeling-off monitoring sensor are arranged at four corners of the surface of the semiconductor substrate, respectively.