Sensor device with sealing structure

• US 8,384,168 B2
• Filed: 04/21/2011
• Issued: 02/26/2013
• Est. Priority Date: 04/21/2011
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Hooper, Stephen R., Daniels, Dwight L., MacDonald, James D., McDonald, William G., Xia, Chunlin C.
• Primary Examiner(s): Caputo, Lisa
• Assistant Examiner(s): ROY, PUNAM P
• Application Number:
  US13/091,997
• Publication Number:
  US 20120266684A1
• Time in Patent Office: 677 Days
• Field of Search: 438/51, 438/52, 438/53, 257/415, 257/419, 257/433
• US Class Current: 257/415
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2207/012 the micromechanical device and the control or processing electronics being separate parts in the same package
• CPC Class Codes: B81B 7/0041 maintaining a controlled atmosphere with techniques not provided for in B81B7/0038
• CPC Class Codes: G01L 19/0672 Leakage or rupture protection or detection
• CPC Class Codes: G01L 19/147 Details about the mounting of the sensor to support or covering means
• CPC Class Codes: G01L 9/0052 of piezoresistive elements circuits therefor G01L9/06
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2924/15151 the die mounting substrate comprising an aperture, e.g. for underfilling, outgassing, window type wire connections
• CPC Class Codes: H01L 2924/16152 Cap comprising a cavity for hosting the device, e.g. U-shaped cap

Abstract

Apparatus and related fabrication methods are provided for a sensor device. The sensor device includes a sensor structure including a first portion having a sensing arrangement formed thereon and a second structure. A sealing structure is interposed between the sensor structure and the second structure, wherein the sealing structure surrounds the first portion of the sensor structure. The sealing structure establishes a fixed reference pressure on a first side of the first portion, and an opposing side of the first portion is exposed to an ambient pressure.

Claims

1. A sensor device comprising:

a sensor structure including a first portion having a sensing arrangement formed thereon;

control circuitry to determine a pressure metric indicative of the ambient pressure based on an electrical signal from the sensing arrangement;

a second structure comprising an integrated circuit die having the control circuitry formed thereon; and

a sealing structure interposed between the sensor structure and the second structure, the sealing structure surrounding the first portion of the sensor structure to establish a fixed reference pressure on a first side of the first portion, wherein a second side of the first portion is exposed to an ambient pressure.

2. The sensor device of claim 1, wherein the sealing structure comprises a metal material bonded to the sensor structure and the second structure to provide an airtight seal between the sensor structure and the second structure.

3. The sensor device of claim 2, the second structure having a planar surface, wherein the metal material is bonded to the planar surface.

4. The sensor device of claim 1, wherein the sealing structure defines a vacuum chamber on the first side of the first portion.

5. The sensor device of claim 1, wherein the fixed reference pressure is at vacuum.

6. The sensor device of claim 1, further comprising a conductive interconnect disposed between the sensor structure and the second structure, wherein the sealing structure and the conductive interconnect each comprise a metal material bonded to the sensor structure and the second structure.

7. The sensor device of claim 6, wherein the conductive interconnect is electrically connected to the sensing arrangement.

8. The sensor device of claim 1, further comprising a conductive interconnect disposed between the sensor structure and the integrated circuit die to provide an electrical connection between the control circuitry and the sensing arrangement.

9. The sensor device of claim 1, wherein the first portion deflects in response to a difference between the ambient pressure and the fixed reference pressure.

10. The sensor device of claim 1, wherein:

the sensor structure comprises a second integrated circuit die;

the first portion comprises a diaphragm region of the second integrated circuit die;

the sensing arrangement is formed on the first side of the diaphragm region; and

the sealing structure defines a vacuum chamber on the first side of the first portion.

11. A pressure sensor device comprising:

a pressure sensor structure including a diaphragm region having a sensing arrangement formed on a first side of the pressure sensor structure, wherein a second side of the diaphragm region is exposed to an ambient pressure;

a metal material circumscribing the diaphragm region, the metal material being bonded to the first side of the pressure sensor structure; and

a substrate having a planar surface, wherein the metal material is bonded to the planar surface of the substrate to establish a chamber on the first side of the diaphragm region having a fixed reference pressure, wherein the substrate comprises a semiconductor substrate having an application-specific integrated circuit formed thereon, the application-specific integrated circuit being coupled to the sensing arrangement to determine a pressure metric indicative of the ambient pressure based on an electrical signal from the sensing arrangement.

12. The pressure sensor device of claim 11, wherein:

the sensing arrangement comprises a plurality of piezoresistive elements formed on the diaphragm region, resistances of the piezoresistive elements being influenced by deflection of the diaphragm region; and

the electrical signal is influenced by the resistances of the plurality of piezoresistive elements.

13. A pressure sensor device comprising:

a pressure sensor structure including a diaphragm region having a sensing arrangement formed on a first side of the pressure sensor structure, wherein a second side of the diaphragm region is exposed to an ambient pressure;

a metal material circumscribing the diaphragm region, the metal material being bonded to the first side of the pressure sensor structure;

a substrate having a planar surface, wherein the metal material is bonded to the planar surface of the substrate to establish a chamber on the first side of the diaphragm region having a fixed reference pressure; and

a protective material formed on the second side of the diaphragm region.

14. The sensor device of claim 13, further comprising a molding compound surrounding the pressure sensor structure and the substrate.

15. A pressure sensor device comprising:

a pressure sensor structure including a diaphragm region having a sensing arrangement formed on a first side of the pressure sensor structure;

a metal material circumscribing the diaphragm region, the metal material being bonded to the first side of the pressure sensor structure;

a substrate having a planar surface, wherein the metal material is bonded to the planar surface of the substrate to establish a chamber having a fixed reference pressure; and

a molding compound disposed between the pressure sensor structure and the substrate, the molding compound surrounding the metal material.

16. The pressure sensor device of claim 15, wherein:

the chamber is disposed on the first side of the diaphragm region; and

a second side of the diaphragm region is exposed to an ambient pressure.

17. The pressure sensor device of claim 15, wherein the fixed reference pressure is at vacuum.

18. The sensor device of claim 15, wherein the molding compound encapsulates the pressure sensor structure and the substrate.

19. A sensor device comprising:

a sensor structure including a cavity and a diaphragm region having a sensing arrangement formed thereon;

a substrate;

a sealing structure bonded to a first side of the sensor structure and the substrate, the sealing structure circumscribing the diaphragm region on the first side of the sensor structure; and

a capping member bonded to the substrate, the capping member covering the sensor structure to establish a fixed reference pressure on a second side of the sensor structure, wherein the substrate includes a hole formed therein, the diaphragm region being aligned with the hole to expose the first side of the diaphragm region opposite the cavity to an ambient pressure.

20. The sensor device of claim 19, further comprising an integrated circuit die having formed thereon control circuitry to determine a pressure metric indicative of the ambient pressure based on an electrical signal from the sensing arrangement, the integrated circuit die being bonded to the substrate and the substrate providing an electrical connection between the sensing arrangement and the control circuitry.