Capacitance type physical quantity sensor having sensor chip and circuit chip

• US 7,272,974 B2
• Filed: 09/15/2005
• Issued: 09/25/2007
• Est. Priority Date: 09/16/2004
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Goto, Keisuke
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US11/226,249
• Publication Number:
  US 20060065053A1
• Time in Patent Office: 740 Days
• Field of Search: 735/143.2, 361/280
• US Class Current: 73/514.32
• 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: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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 capacitance type physical quantity sensor includes a sensor chip and a circuit chip. The sensor chip includes: a support substrate; a semiconductor layer; a movable electrode; and a fixed electrode. The sensor chip is stacked on the circuit chip such that the movable electrode and the fixed electrode face the circuit chip. The movable electrode has a thickness in a stacking direction. The sensor chip has a first distance between the movable electrode and the circuit chip and a second distance between the movable electrode and the support substrate. The thickness of the movable electrode is larger than the first distance and the second distance.

Claims

1. A capacitance type physical quantity sensor comprising:

a sensor chip for detecting a physical quantity; and

a circuit chip for processing a signal outputted from the sensor chip, wherein the sensor chip includes;

a support substrate;

a semiconductor layer disposed on one side of the substrate;

a movable electrode disposed in the semiconductor layer and displaceable in a direction parallel to the substrate in accordance with the physical quantity; and

a fixed electrode disposed in the semiconductor layer and facing the movable electrode,

the sensor chip is capable of detecting the physical quantity on the basis of a capacitance change of a capacitor provided between the movable electrode and the fixed electrode,

the capacitance change is provided by a displacement of the movable electrode in accordance with the physical quantity,

the sensor chip is stacked on the circuit chip in such a manner that the movable electrode and the fixed electrode face the circuit chip,

the sensor chip is electrically connected to the circuit chip,

the movable electrode has a thickness in a stacking direction of the sensor chip,

the sensor chip has a first distance between the movable electrode and the circuit chip and a second distance between the movable electrode and the support substrate, and

the thickness of the movable electrode is larger than the first distance and the second distance, wherein

the circuit chip includes a protection film disposed on one side of the circuit chip, and

the protection film faces the movable electrode so that a distance between a surface of the protection film and the movable electrode provides the first distance.

2. The sensor according to claim 1, wherein

the sensor chip is electrically connected to the circuit chip through a bump electrode.

3. The sensor according to claim 2, wherein

the bump electrode has a thickness in the stacking direction of the sensor chip, and

the thickness of the bump electrode is equal to the first distance.

4. The sensor according to claim 2, wherein

the sensor chip further includes a concavity disposed on a part of the sensor chip,

the bump electrode has a part, which is inserted into the concavity,

the other part of the bump electrode is protruded from the concavity,

the other part of the bump electrode has a thickness in the stacking direction of the sensor chip, and

the thickness of the other part of the bump electrode is equal to the first distance.

5. The sensor according to claim 1, wherein

the protection film is capable of protecting the one side of the circuit chip.

6. The sensor according to claim 1, wherein

the sensor chip further includes an insulation layer disposed between the support substrate and the semiconductor layer, and

the second distance is provided between the movable electrode and the insulation layer.

7. The sensor according to claim 6, wherein

the movable electrode is supported on the substrate through the insulation layer in such a manner that the movable electrode is separated from the substrate by the second distance, and

the movable electrode has a displacement range, which is limited between the insulation layer and the one side of the circuit chip.