Strain sensor and method for manufacturing the same

• US 9,000,547 B2
• Filed: 03/11/2014
• Issued: 04/07/2015
• Est. Priority Date: 09/09/2013
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Higuchi, Kazuhito, Miyagi, Takeshi, Higashi, Yoshihiro, Hara, Michiko, Fukuzawa, Hideaki, Kii, Masayuki, Fujisawa, Eizo, Asano, Yusaku
• Primary Examiner(s): Coleman, William D
• Application Number:
  US14/203,868
• Publication Number:
  US 20150069540A1
• Time in Patent Office: 392 Days
• Field of Search: 257/421, 438/48
• US Class Current: 257/421
• CPC Class Codes: G01L 1/125 by using magnetostrictive means magnetostrictive sensors H10N35/101

Abstract

According to one embodiment, a strain sensor includes a substrate, a lid, a frame, and a sensing unit. The substrate has a first surface. The lid is provided on the first surface. The frame is provided between the substrate and the lid. The frame is nonconductive and includes a magnetic body. The sensing unit is provided inside the frame between the substrate and the lid, and includes a magnetoresistance effect element.

Claims

1. A strain sensor, comprising:

a substrate having a first surface;

a lid provided on the first surface;

a frame provided between the substrate and the lid, the frame being nonconductive and including a magnetic body; and

a sensing unit provided inside the frame between the substrate and the lid, the sensing unit including a magnetoresistance effect element.

2. The sensor according to claim 1, wherein the sensing unit includes:

a fixed portion; and

a movable portion, the magnetoresistance effect element being provided at the movable portion.

3. The sensor according to claim 1, wherein the sensing unit includes a semiconductor substrate, and the magnetoresistance effect element mounted on the semiconductor substrate.

4. The sensor according to claim 1, wherein the magnetoresistance effect element includes:

a fixed layer, an orientation of magnetization of the fixed layer being fixed in a direction along the first surface; and

a free layer, an orientation of magnetization of the free layer not being fixed.

5. The sensor according to claim 1, further comprising a support unit provided between the lid and the sensing unit to contact the lid and the sensing unit.

6. The sensor according to claim 1, wherein the frame is provided around the sensing unit.

7. The sensor according to claim 1, wherein the frame includes a resin portion including the magnetic body.

8. The sensor according to claim 1, wherein the frame includes a magnetic paste having a viscosity not less than 100 Pa·

s (pascal seconds) and not more than 400 Pa·

s, a curing temperature of 150 degrees (°

C.) or less, a glass transition point of 150°

C. or more, an elastic modulus not less than 5 GPa (gigapascals) and not more than 30 GPa, and a linear coefficient of thermal expansion not less than 5 ppm/°

C. and not more than 30 ppm/°

C.

9. The sensor according to claim 1, wherein the lid includes a resin.

10. The sensor according to claim 1, wherein the substrate includes a glass epoxy.

11. The sensor according to claim 1, wherein a side surface of the lid is provided in a same plane of a side surface of the frame and a side surface of the substrate.

12. The sensor according to claim 1, further comprising:

a first interconnect provided along the first surface; and

a bump electrode provided between the sensing unit and the first interconnect.

13. The sensor according to claim 2, wherein the sensing unit is a diaphragm including the fixed portion and the movable portion, the movable portion being provided to be thinner than the fixed portion.

14. The sensor according to claim 2, wherein the movable portion is a movable beam.

15. The sensor according to claim 4, wherein a bias magnetic field is applied to the magnetoresistance effect element.

16. The sensor according to claim 7, wherein

the resin portion includes an epoxy resin, and

the magnetic body is an alloy including nickel, copper, and zinc (Zn).

17. The sensor according to claim 9, wherein the lid is nonconductive and further includes the magnetic body.

18. A method for manufacturing a strain sensor, comprising:

preparing a substrate material having a first surface;

preparing a sensing unit including a magnetoresistance effect element;

mounting the sensing unit on the first surface;

coating a paste material onto the first surface around a periphery of the sensing unit, the paste material being nonconductive and including a magnetic body;

mounting a lid material on the sensing unit with the paste material interposed;

forming a frame by curing the paste material; and

cutting the lid material, the frame, and the substrate material in a direction orthogonal to the first surface.

19. The method according to claim 18, wherein the mounting of the lid material includes mounting the lid material with a support unit interposed between the lid material and the sensing unit.

20. The method according to claim 19, wherein

the preparing of the sensing unit includes preparing a plurality of the sensing units, and

the coating of the paste material includes coating the paste material around peripheries of each of the plurality of sensing units.