Semiconductor physical quantity sensor having movable portion and fixed portion confronted each other and method of manufacturing the same

• US 6,276,207 B1
• Filed: 11/12/1999
• Issued: 08/21/2001
• Est. Priority Date: 11/13/1998
• Status: Expired due to Term

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kawasaki, Eishi, Murata, Minoru, Muto, Hiroshi, Sakai, Minekazu, Takeuchi, Yukihiro, Toyoda, Inao, Ishio, Seiichiro, Yamamoto, Toshimasa
• Primary Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US09/438,293
• Time in Patent Office: 648 Days
• Field of Search: 735/141.6, 735/143.2, 735/143.6
• US Class Current: 73/514.16
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 3/0008 Structures for avoiding electrostatic attraction, e.g. avoiding charge accumulation
• CPC Class Codes: B81B 3/001 Structures having a reduced contact area, e.g. with bumps or with a textured surface
• CPC Class Codes: B81C 1/00928 Eliminating or avoiding remaining moisture after the wet etch release of the movable structure
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type

Abstract

A semiconductor acceleration sensor, which prevents an adhesion of a movable portion to a fixed portion due to an electrostatic force generated during being handled. The acceleration sensor has a sensor portion and a handling portion. The sensor portion has a first semiconductor layer; a movable portion including a weight portion supported to the first semiconductor layer for moving in accordance with an acceleration externally applied thereto and movable electrodes integrally formed with the weight portion; and fixed electrodes having a detection surface confronted to a detection surface of the movable electrodes and supported to the first semiconductor layer. The handling portion is to be contacted during being handled, and is provided at surrounding portion of the sensor portion with a trench interposed therebetween. The sensor portion is electrically insulated from the handling portion by the trench.

Claims

1. A semiconductor physical quantity sensor comprising:

a sensor portion including;

a semiconductor substrate;

a movable portion having a weight portion supported to the semiconductor substrate, for moving in accordance with a physical quantity applied thereto; and

an movable electrode integrally formed with the weight portion and having a detection surface; and

a fixed electrode supported to the semiconductor substrate, and having a detection surface confronted to the detection surface of the movable electrode; and

a handling portion formed on the semiconductor substrate, being insulated from the sensor portion by an insulation portion, and is to be externally contacted when the semiconductor physical quantity sensor is handled.

2. A sensor according to claim 1, wherein said sensor portion has a surrounding portion and the handling portion is formed at said surrounding portion of the sensor portion with the insulation portion interposed therebetween.

3. A sensor according to claim 1, wherein said sensor portion has a whole surrounding portion and the handling portion is formed at the whole surrounding portion of the sensor portion with the insulation portion interposed therebetween.

4. A sensor according to claim 1, wherein:

said semiconductor substrate has at least one surface, and

a semiconductor layer is provided on said at least one surface of the semiconductor substrate,

the insulation portion has a trench to divide the semiconductor layer, and

the sensor portion and the handling portion are made from the semiconductor layer with the trench interposed therebetween, and electrically insulated each other by the trench.

5. A sensor according to claim 1, wherein:

said semiconductor substrate has at least one surface,

a semiconductor layer is provided on said at least one surface of the semiconductor substrate with an insulation layer interposed therebetween and being on an outer side of the sensor portion,

the sensor portion is made from the semiconductor layer,

the insulation layer on said outer side of the sensor portion is partially exposed by partial removal of the semiconductor layer,

the exposed insulation layer has a peripheral end portion, and

the handling portion is defined by the peripheral end portion of the insulation layer.