Acceleration sensor

• US 20060130584A1
• Filed: 09/16/2005
• Published: 06/22/2006
• Est. Priority Date: 12/16/2004
• Status: Active Grant

• Current Assignee: Fujitsu Limited, Fujitsu Media Devices Limited (Fujitsu Limited)
• Original Assignee: Fujitsu Limited, Fujitsu Media Devices Limited (Fujitsu Limited)
• Inventors: Tanaka, Hiroshi, Ono, Masaaki, Ishikawa, Hiroshi, Yamada, Sumio, Ono, Nobuko
• Granted Patent: US 7,296,471 B2
• Time in Patent Office: Days
• US Class Current: 73/514.360
• CPC Class Codes: G01P 1/023 for acceleration measuring devices
• CPC Class Codes: G01P 15/123 by piezo-resistive elements, e.g. semiconductor strain gauges
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/084 the mass being suspended at more than one of its sides, e.g. membrane-type suspension, so as to permit multi-axis movement of the mass
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

A structure with superior shock resistance is proposed for a parasol-type acceleration sensor. The acceleration sensor comprises a support portion the lower end of which is fixed to a substrate; a beam portion on which a detection element for applying changes to an output signal in correspondence with strain caused by acceleration acting on the detection element is formed, one end of the beam portion being connected to the top part of the support portion; a suspended weight connected to the other end of the beam portion; and a stopper substrate with a window portion through which, in order to guide an output signal of the detection element via a pad that is formed on the upper end face of the support portion, a conductor lead that is connected to the pad passes. Overswing of the weight is limited by means of the stopper substrate.

Claims

1. An acceleration sensor, comprising:

a support portion the lower end of which is fixed to a substrate;

a beam portion on which a detection element for applying changes to an output signal in correspondence with strain caused by acceleration acting on the detection element is formed, one end of the beam portion being connected to the top part of the support portion;

a suspended weight connected to the other end of the beam portion; and

a stopper substrate with a window portion through which, in order to guide an output signal of the detection element via a pad that is formed on the upper end face of the support portion, a conductor lead that is connected to the pad passes,

wherein the stopper substrate is fixed by means of adhesive to a region surrounding the pad of the upper end face of the support portion and upward overswing of the weight is limited by means of the stopper substrate.

5. The acceleration sensor according to any one of claims 1 to 3, wherein the support portion, beam portion and weight are integrally formed by means of a semiconductor substrate.

8. The acceleration sensor according to any one claims 1 to 4, wherein the interval between the weight and the stopper substrate is 2 to 12 μ

m.

2. An acceleration sensor, comprising:

a support portion the lower end of which is fixed to a substrate and the upper end face of which includes a pad;

four beam portions the respective one end of which is connected to the upper end portion of the support portion in an orthogonal direction with the support portion at the center and on which a detection element that applies changes to an output signal in correspondence with strain caused by acceleration acting on the detection element is formed;

a suspended weight connected to the other end of the four beam portions;

a support-portion extension part disposed between two adjacent beam portions of the four beam portions; and

a stopper substrate with a window portion through which, in order to guide an output signal of the detection element via a pad that is formed on the upper end face of the support portion, a conductor lead that is connected to the pad passes,

wherein the stopper substrate is fixed by means of adhesive to the extension of the support portion and limits upward overswing of the weight.

7. The acceleration sensor according to claim 2, further comprising:

a groove between the extension of the support portion and the pad formed on the upper end face of the support portion.

3. An acceleration sensor, comprising:

a support portion the lower end of which is fixed to a substrate;

four beam portions the respective one end of which is connected to the upper end portion of the support portion in an orthogonal direction with the support portion at the center and on which a detection element that applies changes to an output signal in correspondence with strain caused by acceleration acting on the detection element is formed;

a suspended weight connected to the other end of the four beam portions;

a support-portion extension that is disposed between two adjacent beam portions of the four beam portions; and

a stopper substrate with a window portion through which, in order to guide an output signal of the detection element via a pad that is formed on the extension of the support portion, a conductor lead that is connected to the pad passes,

wherein the stopper substrate is fixed by means of adhesive to the upper end face of the support portion and limits upward overswing of the weight.

4. An acceleration sensor, comprising:

a support portion the lower end of which is fixed to a substrate;

a beam portion on which a detection element for applying changes to an output signal in correspondence with strain caused by acceleration acting on the detection element is formed, one end of the beam portion being connected to the top part of the support portion;

a suspended weight connected to the other end of the beam portion;

a stopper substrate with a window portion through which, in order to guide an output signal of the detection element via a pad that is formed on the upper end face of the support portion, a conductor lead that is connected to the pad passes; and

a frame portion that surrounds the weight,

wherein the stopper substrate is fixed by means of adhesive to the upper end face of the frame portion and limits upward overswing of the weight.

6. The acceleration sensor according to claim 4, wherein the support portion, beam portion, weight and frame portion are integrally formed by means of a semiconductor substrate and the weight and frame portion are connected by means of a join portion and the frame portion is separated from the weight by cutting the join portion after mounting in the package.