MEMS PRESSURE SENSOR, ELECTRONIC DEVICE, ALTIMETER, ELECTRONIC APPARATUS, AND MOVING OBJECT

• US 20140311241A1
• Filed: 04/21/2014
• Published: 10/23/2014
• Est. Priority Date: 04/22/2013
• Status: Abandoned Application

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: KITANO, Yoji
• Application Number:
  US14/257,328
• Publication Number:
  US 20140311241A1
• Time in Patent Office: Days
• US Class Current: 73/384
• CPC Class Codes: G01L 9/008 using piezoelectric devices piezoelectric resonators G01L9/0022; surface acoustic waves G01L9/0025

Abstract

A MEMS pressure sensor includes a diaphragm portion that becomes displaced according to a pressure, and a resonator arranged on a main surface of the diaphragm portion. The resonator includes: a first fixed electrode provided on the main surface; and a drive electrode having a second fixed electrode provided on the main surface, a movable electrode spaced apart from the first fixed electrode, overlapping with the first fixed electrode, as viewed in a plan view seen from a normal direction to the main surface, and driven in a direction that intersects the main surface, and a supporting electrode supporting the movable electrode and connected to the second fixed electrode.

Claims

1. A MEMS pressure sensor comprising

a diaphragm portion that becomes displaced according to a pressure, and

a resonator arranged on a main surface of the diaphragm portion,

wherein the resonator includes

a first fixed electrode provided on the main surface, and

a drive electrode having a second fixed electrode provided on the main surface, a movable electrode spaced apart from the first fixed electrode, overlapping with the first fixed electrode, as viewed in a plan view seen from a normal direction to the main surface, and driven in a direction that intersects the main surface, and a supporting electrode supporting the movable electrode and connected to the second fixed electrode.

2. The MEMS pressure sensor according to claim 1, wherein the diaphragm portion has a recessed portion arranged on a back side of the main surface, and a thin portion made up of a bottom surface of the recessed portion and the main surface, and

if a distance between opposite ends of the first fixed electrode and the second fixed electrode is a, and

a diameter of an inscribed circle in a planar shape as viewed in a plan view seen from a normal direction to the main surface, of the recessed portion of the diaphragm portion, is b_B,

0<

a≦

0.3b_B

holds.

3. The MEMS pressure sensor according to claim 2, wherein the first fixed electrode is arranged in an area that is concentric with the inscribed circle, having a diameter c in a planar shape as viewed in a plan view seen from a normal direction to the main surface, of the recessed portion of the diaphragm portion, and

the diameter c is

0<

c≦

0.93b_B.

4. The MEMS pressure sensor according to claim 2, wherein if a diameter of a bottom-surface inscribed circle in a planar shape in the bottom surface of the recessed portion is b_B, and

a diameter of an opening inscribed circle in a planar shape in an opening of the recessed portion on the back side is b_W,

as viewed in a plan view seen from a normal direction to the main surface,

b_B<

b_W

holds.

5. The MEMS pressure sensor according to claim 3, wherein if a diameter of a bottom-surface inscribed circle in a planar shape in the bottom surface of the recessed portion is b_B, and

a diameter of an opening inscribed circle in a planar shape in an opening of the recessed portion on the back side is b_W,

as viewed in a plan view seen from a normal direction to the main surface,

b_B<

b_W

holds.

6. An electronic device comprising:

the MEMS pressure sensor according to claim 1; and

a holding unit that holds the opening and the bottom surface of the recessed portion on the back side of the substrate, in a state of being exposed to a pressure changing area.

7. An altimeter comprising:

the MEMS pressure sensor according to claim 1;

a holding unit that holds the opening and the bottom surface of the recessed portion on the back side, in a state of being exposed to a pressure changing area; and

a data processing unit that processes measurement data from the MEMS pressure sensor.

8. An electronic apparatus comprising the MEMS pressure sensor according to claim 1, an electronic device or an altimeter.

9. A moving object comprising the MEMS pressure sensor according to claim 1, a pressure sensor device, an altimeter or an electronic apparatus.