Acceleration sensor and fabrication method thereof

• US 7,900,515 B2
• Filed: 11/28/2007
• Issued: 03/08/2011
• Est. Priority Date: 06/05/2007
• Status: Active Grant

• Current Assignee: Nexgen Control Systems LLC
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Yamaguchi, Yasuo, Murakami, Takeshi, Okumura, Mika, Horikawa, Makio, Sato, Kimitoshi
• Primary Examiner(s): Kwok; Helen C.
• Application Number:
  US11/946,507
• Publication Number:
  US 20080302184A1
• Time in Patent Office: 1,196 Days
• Field of Search: 735/143.2, 735/143.6, 735/143.8, 734/93, 295/921, 257/414, 257/415
• US Class Current: 73/514.32
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2207/07 Interconnects
• CPC Class Codes: B81B 3/0086 Electrical characteristics, e.g. reducing driving voltage, improving resistance to peak voltage
• CPC Class Codes: G01P 1/023 for acceleration measuring devices
• 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
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

First and second semiconductor layers are attached to each other with an insulation layer sandwiched therebetween. An acceleration sensor device is formed in the first semiconductor layer. A control device for controlling the acceleration sensor device is formed on the second semiconductor layer. Through holes are formed in the second semiconductor layer, and an insulation layer is formed to cover the wall surfaces of the through holes. Through interconnections are formed within the through holes for electrically connecting the acceleration sensor device and the control device to each other. Accordingly, it is possible to obtain an acceleration sensor having excellent detection accuracy while having a reduced size, and a fabrication method thereof.

Claims

1. An acceleration sensor, comprising:

a first semiconductor layer;

a first insulation layer on said first semiconductor layer;

a second semiconductor layer on said first insulation layer;

an acceleration sensor device in said first semiconductor layer, said acceleration sensor device including a supporting portion, said supporting portion abutting a surface including a concave portion facing to said acceleration sensor device;

a control device, configured to control said acceleration sensor device, on said second semiconductor layer, said second semiconductor layer including a through hole for electrically connecting said acceleration sensor device and said control device to each other, said through hole reaching said first semiconductor layer, said control device opposing said surface across said acceleration sensor device;

a second insulation layer covering wall surfaces of said through hole; and

a conductive layer within said through hole for electrically connecting said acceleration sensor device and said control device to each other through said second semiconductor layer.

2. The acceleration sensor according to claim 1, further comprising:

a lid member covering said acceleration sensor device.

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

a spacer between said first semiconductor layer and said lid member.

4. The acceleration sensor according to claim 2, wherein said lid member has said surface.

5. The acceleration sensor according to claim 2, wherein said acceleration sensor device includes a mass member movable with respect to said supporting portion, and a surface of said mass member closer to said lid member is recessed with respect to a surface of said supporting portion closer to said lid member, in a direction opposite from a direction toward said lid member.

6. The acceleration sensor according to claim 1, further comprising:

a package housing, therewithin, said acceleration sensor device and said control device and also having an interconnection, wherein said acceleration sensor device and said control device are electrically connected to said interconnection.

7. An acceleration sensor, comprising:

a first semiconductor layer;

an insulation layer on said first semiconductor layer;

a second semiconductor layer on said insulation layer;

an acceleration sensor device in said first semiconductor layer and having an electrode;

a control device, configured to control said acceleration sensor device, on said second semiconductor layer;

a lid member covering said acceleration sensor device and opposing said control device across said acceleration sensor device, said lid member including a through hole reaching said electrode of said acceleration sensor device; and

a conductive layer within said through hole, electrically connecting said acceleration sensor device and said control device to each other through said lid member.

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

a spacer between said first semiconductor layer and said lid member.

9. The acceleration sensor according to claim 7, wherein said lid member has a concave portion in a surface of said lid member, said surface facing to said acceleration sensor device.

10. The acceleration sensor according to claim 7, wherein said acceleration sensor device includes a supporting portion and a mass member movable with respect to said supporting portion, and a surface of said mass member closer to said lid member is recessed with respect to a surface of said supporting portion closer to said lid member, in a direction opposite from a direction toward said lid member.

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

a package housing, therewithin, said acceleration sensor device and said control device and also having an interconnection, wherein said acceleration sensor device and said control device are electrically connected to said interconnection.

12. An acceleration sensor fabrication method, comprising:

preparing a substrate including a first semiconductor layer, a second semiconductor layer and a first insulation layer sandwiched therebetween;

forming a control device on said second semiconductor layer;

forming an acceleration sensor device to be controlled by said control device, in said first semiconductor layer, said acceleration sensor device including a supporting portion;

forming a through hole for electrically connecting said acceleration sensor device and said control device to each other, in the second semiconductor layer, said through hole reaching said first semiconductor layer;

forming a second insulation layer to cover wall surfaces of said through hole;

forming a conductive layer for electrically connecting said acceleration sensor device and said control device to each other through the second semiconductor layer, within said through hole; and

mounting a surface to abut said supporting portion, said surface including a concave portion facing to said acceleration sensor device, said surface opposing said control device across said acceleration sensor device.

13. An acceleration sensor fabrication method, comprising:

forming an acceleration sensor device in a first semiconductor layer, said acceleration sensor device including a supporting portion;

forming a control device, configured to control said acceleration sensor device, on a second semiconductor layer, and forming a through hole through said second semiconductor layer, said through hole reaching said first semiconductor layer;

attaching said first semiconductor layer in which said acceleration sensor device is formed and said second semiconductor layer on which said control device is formed to each other with a first insulation layer sandwiched therebetween;

forming a second insulation layer to cover wall surfaces of said through hole;

forming a conductive layer for electrically connecting said acceleration sensor device and said control device to each other through said second semiconductor layer, within said through hole; and

mounting a surface to abut said supporting portion, said surface including a concave portion facing to said acceleration sensor device, said surface opposing said control device across said acceleration sensor device.