Physical quantity sensor, manufacturing method of physical quantity sensor, sensor device, electronic apparatus, and moving object

• US 10,035,697 B2
• Filed: 09/26/2016
• Issued: 07/31/2018
• Est. Priority Date: 09/29/2015
• Status: Active Grant

• Current Assignee: Crystal Leap Zrt
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Tanaka, Satoru
• Primary Examiner(s): Sarkar, Asok K
• Assistant Examiner(s): WITHERS, GRANT S
• Application Number:
  US15/275,831
• Publication Number:
  US 20170088413A1
• Time in Patent Office: 673 Days
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2203/0181 See-saws
• CPC Class Codes: B81B 3/001 Structures having a reduced contact area, e.g. with bumps or with a textured surface
• CPC Class Codes: B81B 3/0072 For controlling internal stress or strain in moving or flexible elements, e.g. stress compensating layers
• CPC Class Codes: B81C 1/00666 Treatments for controlling internal stress or strain in MEMS structures
• CPC Class Codes: B81C 1/00952 Treatments or methods for avoiding stiction during the manufacturing process not provided for in groups B81C1/00928 - B81C1/00944
• CPC Class Codes: B81C 2203/0118 Bonding a wafer on the substrate, i.e. where the cap consists of another wafer
• CPC Class Codes: B81C 2203/031 Anodic bondings

Abstract

A physical quantity sensor includes a base substrate; a movable unit which is provided so as to be displaced with respect to the base substrate by facing the base substrate; a first fixed electrode and a second fixed electrode which are disposed on the base substrate by facing the movable unit; and a plurality of protrusion portions which are disposed at a position overlapped with the movable unit in a planar view, on the movable unit side of the base substrate, in which the protrusion portion includes a conductive layer with the same potential as that of the first fixed electrode and the second fixed electrode, and an insulating layer which is provided on a side opposite to the base substrate with respect to the conductive layer.

Claims

1. A physical quantity sensor comprising:

a substrate;

a fixed electrode which is disposed on the substrate, the fixed electrode being generally in a rectangular shape with four corners;

a movable body which is provided above the fixed electrode via a gap, the movable body being movable with respect to the fixed electrode, the movable body being generally in a rectangular shape with four corners; and

a protrusion which is disposed at a position overlapped with the movable body in a plan view on the substrate,

wherein the protrusion is configured by stacked layers including a conductive layer and an insulating layer, and the conductive layer is directly provided on the fixed electrode so that the conductive layer has a same potential as the fixed electrode, and

the physical quantity sensor detects a capacitance change between the fixed electrode and the movable body.

2. The physical quantity sensor according to claim 1,

wherein the protrusion is overlapped with the fixed electrode in the plan view, and

the conductive layer is configured integrally with the fixed electrode.

3. The physical quantity sensor according to claim 2,

wherein a projection part of the protrusion is configured integrally with the substrate, and

the conductive layer is provided on the projection part of the protrusion.

4. The physical quantity sensor according to claim 2,

wherein the insulating layer is a silicon oxide film.

5. The physical quantity sensor according to claim 2,

wherein the movable body is provided so as to oscillate around an oscillation center axis, the movable body is sectioned into a first movable member and a second movable member, and the oscillation center axis is a boundary between the first and second movable members, and

wherein the fixed electrode in configured with a first fixed electrode and a second fixed electrode, the first fixed electrode is disposed on the substrate so as to face the first movable member, and the second fixed electrode is disposed on the substrate so as to face the second movable member.

6. The physical quantity sensor according to claim 5,

wherein an area of the second movable member is larger than an area of the first movable member in the plan view.

7. The physical quantity sensor according to claim 1,

wherein a projection part of the protrusion is configured integrally with the substrate, and

the conductive layer is provided on the projection part of the protrusion.

8. The physical quantity sensor according to claim 7,

wherein the insulating layer is a silicon oxide film.

9. The physical quantity sensor according to claim 7,

wherein the movable body is provided so as to oscillate around an oscillation center axis, the movable body is sectioned into a first movable member and a second movable member, and the oscillation center axis is a boundary between the first and second movable members, and

wherein the fixed electrode is configured with a first fixed electrode and a second fixed electrode, the first fixed electrode is disposed on the substrate so as to face the first movable member, and the second fixed electrode is disposed on the substrate so as to face the second movable member.

10. The physical quantity sensor according to claim 9,

wherein an area of the second movable member is larger than an area of the first movable member in the plan view.

11. The physical quantity sensor according to claim 1,

wherein the insulating layer is a silicon oxide film.

12. The physical quantity sensor according to claim 11,

wherein the movable body is provided so as to oscillate around an oscillation center axis, the movable body is sectioned into a first movable member and a second movable member, and the oscillation center axis is a boundary between the first and second movable members, and

wherein the fixed electrode is configured with a first fixed electrode and a second fixed electrode, the first fixed electrode is disposed on the substrate so as to face the first movable member, and the second fixed electrode is disposed on the substrate so as to face the second movable member.

13. The physical quantity sensor according to claim 12,

wherein an area of the second movable member is larger than an area of the first movable member in the plan view.

14. The physical quantity sensor according to claim 1,

wherein the movable body is provided so as to oscillate around an oscillation center axis, the movable body is sectioned into a first movable member and a second movable member, and the oscillation center axis is a boundary between the first and second movable members, and

wherein the fixed electrode is configured with a first fixed electrode and a second fixed electrode, the first fixed electrode is disposed on the substrate so as to face the first movable member, and the second fixed electrode is disposed on the substrate so as to face the second movable member.

15. The physical quantity sensor according to claim 14,

wherein an area of the second movable member is larger than an area of the first movable member in the plan view.

16. A sensor device comprising:

the physical quantity sensor according to claim 1; and

an electronic component which is electrically connected to the physical quantity sensor.

17. An electronic apparatus comprising:

the physical quantity sensor according to claim 1;

a display; and

a housing that houses the physical quantity sensor and the display.

18. A moving object comprising:

the physical quantity sensor according to claim 1; and

a movable body that houses the physical quantity sensor.