Semiconductor sensor

• US 7,406,870 B2
• Filed: 12/14/2005
• Issued: 08/05/2008
• Est. Priority Date: 01/06/2005
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Seto, Masami
• Primary Examiner(s): Kwok; Helen C.
• Application Number:
  US11/302,789
• Publication Number:
  US 20060144144A1
• Time in Patent Office: 965 Days
• Field of Search: 735/143.3, 735/143.4, 735/143.6, 735/143.8, 735/142.9, 338/2, 338/5
• US Class Current: 73/514.33
• 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

Abstract

A semiconductor sensor is disclosed that includes a proof mass, a frame that is arranged around the proof mass, a beam that is arranged at the surface side of the frame and is configured to support the proof mass, plural piezo-resistive elements arranged on the beam, plural metal wiring patterns and pad electrodes that are arranged on the surface of the frame and are electrically connected to the piezo-resistive elements, a cover plate that is fixed to the surface of the frame and is arranged to be spaced apart from the proof mass and the beam, and a cover plate fixing region for fixing the cover plate to the surface of the frame, the cover plate fixing region including a formation region for the metal wiring patterns.

Claims

1. A semiconductor sensor comprising:

a proof mass;

a frame that is arranged around the proof mass;

a beam that is arranged at a surface side of the frame and is configured to support the proof mass;

a plurality of piezo-resistive elements arranged on the beam;

an insulating film arranged on the surface side of said frame and beam supporting said proof mass of said semiconductor sensor, and said insulating film having through-holes corresponding to edge positions of the piezo-resistive elements;

a plurality of metal wiring patterns and a plurality of pad electrodes arranged on the insulating film, said metal wiring patterns passing through said through-holes of said insulating film to electrically connect to the piezo-resistive elements;

a cover plate that is fixed to the surface side of the frame via the insulating flim and is arranged to be spaced apart from the proof mass and the beam; and

a cover plate fixing region for fixing the cover plate to the surface side of the frame, the cover plate fixing region including a formation region for the metal wiring patterns.

2. The semiconductor sensor as claimed in claim 1, wherein the cover plate fixing region is arranged to surround the proof mass and the beam.

3. The semiconductor sensor as claimed in claim 2, wherein the pad electrodes are collectively arranged along one side edge of the frame.

4. The semiconductor sensor as claimed in claim 1, wherein the cover plate is a transparent glass plate that allows the proof mass and the beam to be visible.

5. The semiconductor sensor as claimed in claim 1, wherein the surface of the frame is made of a silicon layer, and the cover plate is a glass plate that is fixed to the cover plate fixing region through anodic bonding.

6. The semiconductor sensor as claimed in claim 1, wherein the cover plate is a welded glass plate that is fixed to the cover plate fixing region through welding.

7. The semiconductor sensor as claimed in claim 1, wherein the cover plate is fixed to the cover plate fixing region by adhesive.

8. The semiconductor device as claimed in claim 1, wherein the cover plate fixing region includes a dummy pattern that is simultaneously created with the metal wiring patterns, and a height of the cover plate fixing region is uniform.

9. The semiconductor sensor as claimed in claim 1, wherein the beam and the surface of the frame are made of a same silicon layer, and a dummy pattern is arranged in the cover plate fixing region and on the silicon layer via said insulating film.

10. The semiconductor sensor as claimed in claim 1, wherein the beam and the surface of the frame are made of a same silicon layer, and a dummy pattern is arranged in the cover plate fixing region and is electrically connected to the silicon layer, via a through hole that is arranged in the insulating film.

11. The semiconductor sensor as claimed in claim 10, wherein the dummy pattern is not electrically connected to any or the piezo-resistive elements, the metal wiring patterns, and the pad electrodes.

12. The semiconductor sensor as claimed in claim 1, wherein the beam and the surface of the frame are made of a same silicon layer, and a dummy pattern is arranged in the cover plate fixing region and is electrically connected to the silicon layer, such that the dummy patterns is set to the same potential as that of the silicon layer.

13. The semiconductor sensor as claimed in claim 1, further comprising a substrate and a glass pedestal attached to a rear face of said substrate.

14. A semiconductor sensor comprising:

a proof mass;

a frame that is arranged around the proof mass;

a beam that is arranged at a surface side of the frame and is configured to support the proof mass;

a plurality of piezo-resistive elements arranged on the beam;

an insulating film arranged on the surface side of said frame and on a surface of the beam, and said insulating film having through-holes corresponding to edge positions of the piezo-resistive elements;

a plurality of metal wiring patterns and a plurality of pad electrodes arranged on the insulating film, said metal wiring patterns passing through said through-holes of said insulating film to electrically connect to the piezo-resistive elements;

a cover plate that is fixed to the surface side of the frame via the insulating film and is arranged to be spaced apart from the proof mass and the beam; and

a cover plate fixing region for fixing the cover plate to the surface side of the frame,

wherein the beam and the surface side of the frame are made of a same silicon layer, and the cover plate fixing region includes a dummy pattern electrically connected to the silicon layer, via a through hole that is arranged in the insulating film.

15. The semiconductor sensor as claimed in claim 14, wherein the dummy pattern is not electrically connected to any of the piezo-resistive elements, the metal wiring patterns, and the pad electrodes.

16. The semiconductor sensor as claimed in claim 14, wherein the dummy pattern is arranged on the silicon layer via said insulating film.

17. The semiconductor sensor as claimed in claim 14, wherein the dummy pattern is arranged on a peripheral regions of the cover plate fixing region.