Methods for fabricating sensor device package using a sealing structure

• US 8,476,087 B2
• Filed: 04/21/2011
• Issued: 07/02/2013
• 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): Garber, Charles
• Assistant Examiner(s): STEVENSON, ANDRE C
• Application Number:
  US13/092,001
• Publication Number:
  US 20120270354A1
• Time in Patent Office: 803 Days
• Field of Search: 435/17
• US Class Current: 438/17
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81C 1/0023 Packaging together an electronic processing unit die and a micromechanical structure die MEMS packages B81B7/0032; MEMS packaging processes B81C1/00261
• CPC Class Codes: G01L 19/141 Monolithic housings, e.g. molded or one-piece housings
• CPC Class Codes: G01L 19/148 Details about the circuit board integration, e.g. integrated with the diaphragm surface or encapsulation
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item

Abstract

Fabrication methods are provided for a sensor device packages. An exemplary fabrication method involves bonding a sensor structure and another structure using a sealing structure. The sealing structure surrounds a diaphragm region of the sensor structure and provides an airtight seal between the sensor structure and the other structure to establish a fixed reference pressure on one side of the diaphragm region.

Claims

1. A method of fabricating a sensor device including a sensor structure having a diaphragm region, the method comprising:

bonding the sensor structure and a first structure using a sealing structure, wherein the sealing structure surrounds the diaphragm region and provides an airtight seal between the sensor structure and the first structure to establish a fixed reference pressure on a first side of the diaphragm region; and

forming a molding compound surrounding the sensor structure and the first structure, a second side of the diaphragm region being exposed to an ambient pressure, wherein the molding compound is disposed between the sensor structure and the first structure and surrounds the sealing structure.

2. The method of claim 1, the sealing structure comprising a metal material formed on one of the sensor structure or the first structure, wherein bonding the sensor structure and the first structure comprises bonding the metal material to an other of the sensor structure or the first structure.

3. The method of claim 2, further comprising forming a conductive interconnect comprising the metal material on the one of the sensor structure or the first structure concurrently to forming the sealing structure, wherein bonding the metal material to the other of the sensor structure or the first structure comprises concurrently bonding the conductive interconnect to the other of the sensor structure or the first structure to provide an electrical connection between the sensor structure and the first structure.

4. The method of claim 2, further comprising forming the metal material on a bonding region on the one of the sensor structure or the first structure prior to bonding the sensor structure and the first structure.

5. The method of claim 4, wherein forming the metal material comprises plating the metal material on the bonding region.

6. The method of claim 4, wherein bonding the sensor structure and the first structure comprises bonding the metal material to a second bonding region on the other of the sensor structure or the first structure, the second bonding region corresponding to the bonding region on the one of the sensor structure or the first structure.

7. The method of claim 1, further comprising providing an electrical connection between a sensing arrangement formed on the diaphragm region and control circuitry formed on the first structure concurrently to bonding the sensor structure and the first structure, the control circuitry to determine a pressure metric indicative of ambient pressure on the second side of the diaphragm region based on an electrical signal from the sensing arrangement.

8. The method of claim 1, further comprising forming a metal material on one of the sensor structure or the first structure, the sealing structure comprising the metal material, wherein bonding the sensor structure and the first structure comprises bonding the metal material to an other of the sensor structure or the first structure.

11. The method of claim 1, further comprising mounting the second side of the sensor structure to a second structure, wherein the second structure includes a hole aligned with the diaphragm region to expose the second side of the diaphragm region to the ambient pressure.

12. The method of claim 11, wherein forming the molding compound comprises forming the molding compound overlying the sensor structure and the first structure to encapsulate the sensor structure and the first structure.

13. The method of claim 11, further comprising providing electrical connections between the sensor structure and the second structure.

14. The method of claim 13, further comprising performing a saw-to-reveal process after bonding the sensor structure and the first structure to expose peripheral portions of the sensor structure, wherein providing the electrical connections comprises forming conductive wire bonds between the peripheral portions of the sensor structure and the second structure.

9. A method for fabricating a sensor device, the method comprising:

forming a metal material on one of a sensor structure or a first structure;

bonding the metal material to an other of the sensor structure or the first structure, wherein the metal material provides an airtight seal between the sensor structure and the first structure to establish a fixed pressure on a topside of a diaphragm region of the sensor structure, wherein a backside of the sensor structure includes a cavity;

affixing the backside of the sensor structure to a frame structure having an opening aligned with the diaphragm region after bonding the metal material to the first structure, the opening exposing the cavity to an ambient pressure; and

forming a molding compound overlying the sensor structure and the first structure after affixing the backside of the sensor structure to the frame structure.

10. The method of claim 9, further comprising forming a conductive interconnect of the metal material on the one of the sensor structure or the first structure, the conductive interconnect providing an electrical connection to a sensing arrangement on the diaphragm region after bonding the metal material to the other of the sensor structure or the first structure.

15. A method of fabricating a sensor device including a sensor structure having a diaphragm region, the method comprising:

bonding the sensor structure and a first structure using a sealing structure, wherein the sealing structure surrounds the diaphragm region and provides an airtight seal between the sensor structure and the first structure to establish a fixed reference pressure on a first side of the diaphragm region;

forming a molding compound surrounding the sensor structure and the first structure, wherein a second side of the diaphragm region is exposed to an ambient pressure; and

forming a layer of protective material on the second side of the sensor structure after forming the molding compound, the second side of the sensor structure including a cavity.

16. The method of claim 15, wherein forming the layer of protective material comprises depositing the protective material to a thickness less than 10 microns.

17. A method of fabricating a sensor device including a sensor structure having a diaphragm region and a cavity, the method comprising:

bonding a first side of the sensor structure and a first structure having an opening aligned with the diaphragm region to expose the first side of the diaphragm region opposite the cavity to an ambient pressure using a sealing structure that surrounds the diaphragm region and provides an airtight seal between the sensor structure and the first structure on the first side of the diaphragm region; and

bonding a capping member covering a second side of the sensor structure to the first structure after bonding the first side of the sensor structure and the first structure to establish a fixed reference pressure on the second side of the diaphragm region opposite the first side, the second side of the sensor structure including the cavity.

18. The method of claim 17, further comprising bonding a second structure to the first structure, wherein the first structure provides an electrical connection between the sensor structure and the second structure.

19. The method of claim 18, wherein bonding the second structure comprises bonding the second structure to the first structure concurrently to bonding the sensor structure and the first structure.