Semiconductor device

• US 8,151,642 B2
• Filed: 10/29/2008
• Issued: 04/10/2012
• Est. Priority Date: 10/30/2007
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Nakatani, Goro
• Primary Examiner(s): Noori, Max
• Application Number:
  US12/289,491
• Publication Number:
  US 20090107239A1
• Time in Patent Office: 1,259 Days
• Field of Search: 73510-511, 735/140.1
• US Class Current: 73/510
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2203/04 Electrodes
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type
• CPC Class Codes: G01P 2015/082 for two degrees of freedom of movement of a single mass

Abstract

A semiconductor device according to the present invention includes a semiconductor substrate and an MEMS sensor provided on the semiconductor substrate. The MEMS sensor includes a first electrode having a plurality of first interdigital portions aligned in a prescribed direction X at an interval, a second electrode, having a plurality of second interdigital portions aligned in the direction X at an interval, so arranged that the second interdigital portions are opposed to the first interdigital portions in the direction X respectively, a third electrode having a plurality of third interdigital portions aligned in a direction Y orthogonal the direction X at an interval, a fourth electrode, having a plurality of fourth interdigital portions aligned in the direction Y at an interval, so arranged that the fourth interdigital portions are opposed to the third interdigital portions in the direction Y respectively, and a fifth electrode opposed to the first electrode, the second electrode, the third electrode and the fourth electrode in a direction Z orthogonal to the direction X and the direction Y.

Claims

1. A semiconductor device including:

a semiconductor substrate; and

an MEMS sensor provided on the semiconductor substrate, wherein

the MEMS sensor comprises;

a first electrode having a plurality of first interdigital portions aligned in a prescribed direction X at an interval;

a second electrode, having a plurality of second interdigital portions aligned in the direction X at an interval, so arranged that the second interdigital portions are opposed to the first interdigital portions in the direction X respectively;

a third electrode having a plurality of third interdigital portions aligned in a direction Y orthogonal to the direction X at an interval;

a fourth electrode, having a plurality of fourth interdigital portions aligned in the direction Y at an interval, so arranged that the fourth interdigital portions are opposed to the third interdigital portions in the direction Y respectively;

a fifth electrode opposed to the first electrode, the second electrode, the third electrode and the fourth electrode in a direction Z orthogonal to the direction X and the direction Y;

an X-directional capacitor being formed from each first interdigital portion and each respective second interdigital portion opposed thereto in the direction X;

a Y-directional capacitor being formed from each third interdigital portion and each respective fourth interdigital portion opposed thereto in the direction Y; and

a Z-directional capacitor being formed from each of vibratory ones of the first to fourth electrodes, and the fifth electrode, the fifth electrode being opposed to the first to fourth electrodes in the direction Z.

2. The semiconductor device according to claim 1, further including an X-directional acceleration detector for detecting X-directional acceleration acting on the MEMS sensor on the basis of a change in the capacitance of the X-directional capacitor.

3. The semiconductor device according to claim 1, further including a Y-directional acceleration detector for detecting Y-directional acceleration acting on the MEMS sensor on the basis of a change in the capacitance of the Y-directional capacitor.

4. The semiconductor device according to claim 2, further including a Y-directional acceleration detector for detecting Y-directional acceleration acting on the MEMS sensor on the basis of a change in the capacitance of the Y-directional capacitor.

5. The semiconductor device according to claim 1, further including a Z-directional acceleration detector for detecting Z-directional acceleration acting on the MEMS sensor on the basis of a change in the capacitance of the Z-directional capacitor.

6. The semiconductor device according to claim 4, further including a Z-directional acceleration detector for detecting Z-directional acceleration acting on the MEMS sensor on the basis of a change in the capacitance of the Z-directional capacitor.

7. The semiconductor device according to claim 1, wherein

the first electrode and the second electrode constitute an X-directional pair for detecting X-directional acceleration,

the third electrode and the fourth electrode constitute a Y-directional pair for detecting Y-directional acceleration,

the MEMS sensor includes a plurality of X-directional pairs and a plurality of Y-directional pairs, and

the X-directional pairs and the Y-directional pairs are so arranged that the X-directional pairs are aligned in the direction X, the Y-directional pairs are aligned in the direction X, and the X-directional pairs and the Y-directional pairs are aligned in the direction Y.

8. The semiconductor device according to claim 1, wherein

the first electrode and the second electrode constitute an X-directional pair for detecting X-directional acceleration,

the third electrode and the fourth electrode constitute a Y-directional pair for detecting Y-directional acceleration,

the MEMS sensor includes a plurality of X-directional pairs and a plurality of Y-directional pairs, and

the X-directional pairs and the Y-directional pairs are so arranged that the X-directional pairs are not aligned in the direction X and the Y-directional pairs are not aligned in the direction X, but the X-directional pairs and the Y-directional pairs are aligned in the direction Y.