ACCELERATION SENSOR AND FABRICATION METHOD THEREOF

• US 20080302184A1
• Filed: 11/28/2007
• Published: 12/11/2008
• 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
• Granted Patent: US 7,900,515 B2
• Time in Patent Office: Days
• 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 formed on said first semiconductor layer;

a second semiconductor layer formed on said first insulation layer;

an acceleration sensor device formed in said first semiconductor layer;

a control device for controlling said acceleration sensor device formed 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 acceleration sensor further comprising;

a second insulation layer formed to cover the wall surface of said through hole; and

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

2. The acceleration sensor according to claim 1, further comprising a lid member formed to cover said acceleration sensor device.

3. The acceleration sensor according to claim 2, further comprising a spacer placed between said first semiconductor layer in which said acceleration sensor device is formed and said lid member.

4. The acceleration sensor according to claim 2, wherein said lid member has a concave portion formed in its surface facing to said acceleration sensor device.

5. The acceleration sensor according to claim 2, wherein

said acceleration sensor device includes a supporting portion and a mass member movable with respect to said supporting portion, and

the surface of said mass member closer to said lid member is recessed with respect to the surface of said supporting portion closer to said lid member, in the direction opposite from the direction toward said lid member.

6. The acceleration sensor according to claim 1, further comprising a package for 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 formed on said first semiconductor layer;

a second semiconductor layer formed on said insulation layer;

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

a control device for controlling said acceleration sensor device formed on said second semiconductor layer; and

a lid member formed to cover said acceleration sensor device,

said lid member including a through hole reaching said electrode of said acceleration sensor device, said acceleration sensor further comprising

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

8. The acceleration sensor according to claim 7, further comprising a spacer placed between said first semiconductor layer in which said acceleration sensor device is formed and said lid member.

9. The acceleration sensor according to claim 7, wherein said lid member has a concave portion formed in its 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

the surface of said mass member closer to said lid member is recessed with respect to the surface of said supporting portion closer to said lid member, in the direction opposite from the direction toward said lid member.

11. The acceleration sensor according to claim 7, further comprising a package for 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 the steps of:

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;

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

forming a second insulation layer to cover the wall surface of said through hole; and

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

13. An acceleration sensor fabrication method comprising the steps of:

forming an acceleration sensor device in a first semiconductor layer;

forming a control device for controlling said acceleration sensor device on a second semiconductor layer and forming a through hole through said second 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 the wall surface of said through hole; and

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