PIEZORESISTIVE TYPE Z-AXIS ACCELEROMETER

• US 20130091949A1
• Filed: 05/31/2012
• Published: 04/18/2013
• Est. Priority Date: 10/12/2011
• Status: Active Grant

• Current Assignee: RichWave Technology Corp
• Original Assignee: RichWave Technology Corp
• Inventors: HUANG, Chih-Wei, CHANG, Chieh-Pin, CHEN, Ja-Hao, JUANG, Ying-Zong, WONG, Shyh-Chyi, WANG, Yeong-Her, CHAO, Chuan-Jane
• Granted Patent: US 9,052,332 B2
• Time in Patent Office: Days
• US Class Current: 73/514.34
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/123 by piezo-resistive elements, e.g. semiconductor strain gauges
• CPC Class Codes: G01P 2015/0837 the mass being suspended so as to only allow movement perpendicular to the plane of the substrate, i.e. z-axis sensor

Abstract

A pizeoresistive type Z-axis accelerometer is provided, including a substrate; a plurality of anchors formed over the substrate; a plurality of cantilever beams, wherein the cantilever beams include a piezoresistive material; and a proof mass, wherein the proof mass is suspended over the substrate by respectively connecting the proof mass with the anchors, and the accelerometer senses a movement of the proof mass by the piezoresistive material.

Claims

1. A piezoresistive type Z-axis accelerometer, comprising:

a substrate;

a plurality of anchors formed over the substrate;

a plurality of cantilever beams, wherein the cantilever beams comprise a piezoresistive material; and

a proof mass, wherein the proof mass is suspended over the substrate by respectively connecting the proof mass with the anchors, and the accelerometer senses a movement of the proof mass by the piezoresistive material.

2. The piezoresistive type Z-axis accelerometer as claimed in claim 1, wherein the anchors and the cantilever beams comprise a pair of anchors of a symmetrical structure and a pair of cantilever beams of a symmetrical structure.

3. The piezoresistive type Z-axis accelerometer as claimed in claim 1, wherein anchors and the cantilever beams comprise two pairs of anchors of a symmetrical structure and two pairs of cantilever beams of a symmetrical structure.

4. The piezoresistive type Z-axis accelerometer as claimed in claim 1, wherein the anchors and the cantilever beams comprise a pair of anchors of an asymmetrical structure and a pair of cantilever beams of an asymmetrical structure.

5. The piezoresistive type Z-axis accelerometer as claimed in claim 1, further comprising a supporting frame formed over the substrate and surrounding the anchors, the cantilever beams and the proof mass, wherein the anchors are integrated with the supporting frame.

6. The piezoresistive type Z-axis accelerometer as claimed in claim 1, wherein the support frame comprises an insulating layer, a plurality of dielectric layers, a the dielectric layer and the conductive layers are interleaved with each other and are disposed between the insulating layer and the passivation layer.

7. The piezoresistive type Z-axis accelerometer as claimed in claim 1, wherein the piezoresistive material comprises polysilicon.

8. The piezoresistive type Z-axis accelerometer as claimed in claim 1, wherein the piezoresistive material in the cantilever beams is electrically connected in series.

9. The piezoresistive type Z-axis accelerometer as claimed in claim 1, wherein the proof mass comprises one or more dielectric layers and one or more conductive layers.

10. The piezoresistive type Z-axis accelerometer as claimed in claim 6, wherein the anchors, the cantilever beams and the proof mass define a cavity therebetween.

11. The piezoresistive type Z-axis accelerometer as claimed in claim 1, wherein the cantilever beams are connected with two adjacent sides of the proof mass.

12. The piezoresistive type Z-axis accelerometer as claimed in claim 1, wherein the cantilever beams are connected with three sides of the proof mass, and any two of the cantilever beams are adjacent to each other.

13. The piezoresistive type Z-axis accelerometer as claimed in claim 1, wherein the proof mass is formed with a rectangular configuration from a top view thereof.