MEMS DEVICES AND METHODS FOR FORMING SAME

• US 20150197419A1
• Filed: 01/16/2014
• Published: 07/16/2015
• Est. Priority Date: 01/16/2014
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Cheng, Chun-Wen, Peng, Jung-Huei, Tsai, Shang-Ying, Tsai, Hung-Chia, Teng, Yi-Chuan
• Granted Patent: US 9,352,956 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2203/0315 Cavities
• CPC Class Codes: B81B 2207/098 Arrangements not provided for in groups B81B2207/092 - B81B2207/097
• CPC Class Codes: B81B 7/0006 Interconnects
• CPC Class Codes: B81B 7/02 containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS] B81B7/04 takes precedence
• 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: B81C 2203/0154 Moulding a cap over the MEMS device
• CPC Class Codes: B81C 2203/0714 Forming the micromechanical structure with a CMOS process
• CPC Class Codes: H01L 21/78 with subsequent division of the substrate into plural individual devices cutting to change the surface-physical characteristics or shape of semiconductor bodies H01L21/304
• CPC Class Codes: H01L 23/053 the container being a hollow construction and having an insulating or insulated base as a mounting for the semiconductor body
• CPC Class Codes: H01L 23/31 characterised by the arrangement or shape
• CPC Class Codes: H01L 2924/16152 Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H01L 2924/16235 Connecting to a semiconductor or solid-state bodies, i.e. cap-to-chip

Abstract

An embodiment is MEMS device including a first MEMS die having a first cavity at a first pressure, a second MEMS die having a second cavity at a second pressure, the second pressure being different from the first pressure, and a molding material surrounding the first MEMS die and the second MEMS die, the molding material having a first surface over the first and the second MEMS dies. The device further includes a first set of electrical connectors in the molding material, each of the first set of electrical connectors coupling at least one of the first and the second MEMS dies to the first surface of the molding material, and a second set of electrical connectors over the first surface of the molding material, each of the second set of electrical connectors being coupled to at least one of the first set of electrical connectors.

Claims

1. A method comprising:

forming a first a microelectromechanical system (MEMS) die having a first cavity, the first cavity having a first pressure;

forming a second MEMS die having a second cavity, the second cavity having a second pressure, the second pressure being different from the first pressure;

encapsulating the first MEMS die and the second MEMS die with a molding material, the molding material having a first surface;

forming a first set of electrical connectors in the molding material, each of the first set of electrical connectors coupling at least one of the first and the second MEMS dies to the first surface of the molding material; and

forming a second set of electrical connectors over the first surface of the molding material, each of the second set of electrical connectors being coupled to at least one of the first set of electrical connectors.

2. The method of claim 1 further comprising forming a third MEMS die having a third cavity, the third cavity having a third pressure, the third pressure being different from the first pressure and the second pressure.

3. The method of claim 2, wherein the first pressure is a high pressure, the second pressure is a low pressure, and the third pressure is an ambient pressure.

4. The method of claim 2, wherein the first MEMS die comprises an accelerometer, the second die comprises a gyroscope, and the third MEMS die comprises a pressure sensor.

5. The method of claim 1 further comprising forming an application-specific integrated circuit (ASIC) die, the ASIC die comprising an active device, wherein the encapsulating the first MEMS die and the second MEMS die with a molding material further comprises encapsulating the ASIC die.

6. The method of claim 5, wherein each of the first MEMS die, the second MEMS dies, and the ASIC die have a surface substantially coplanar with a second surface of the molding material, the second surface being opposite of the first surface.

7. The method of claim 5 further comprising:

attaching the first MEMS die to a first surface of the ASIC die; and

attaching the second MEMS die to the first surface of the ASIC die, at least a portion of the molding material extending between the first and the second MEMS dies to the first surface of the ASIC die.

8. The method of claim 1 wherein the forming the first set of electrical connectors in the molding material comprises performing a wire bonding.

9. The method of claim 1 wherein the forming the first set of electrical connectors in the molding material comprises electrical plating.

10. The method of claim 1 further comprising:

forming redistribution lines (RDLs) over the first surface of the molding material and the first MEMS die and the second MEMS die, the RDLs being coupled to the first set of electrical connectors;

forming a dielectric layer over the RDLs and the first surface of the molding material;

forming openings through the dielectric layer to expose surfaces of the RDLs;

forming under bump metallizations (UBMs) in the openings and extending over the dielectric layer, the UBMs being coupled to the RDLs; and

forming the second set of electrical connectors over and electrically coupled to the UBMs, the second set of electrical connectors comprising solder balls.

11. A method comprising:

forming a microelectromechanical system (MEMS) wafer, the MEMS wafer having a first MEMS structure, a second MEMS structure, and a third MEMS structure;

bonding a cap wafer to the MEMs wafer, the bonding forming a first cavity over the first MEMS structure, a second cavity over the second MEMS structure, and a third cavity over the third MEMS structure;

singulating the MEMS wafer forming a first MEMS die comprising the first MEMS structure and the first cavity, a second MEMS die comprising the second MEMS structure and the second cavity, and a third MEMS die comprising the third MEMS structure and the third cavity;

attaching the first MEMS die, the second MEMS die, and the third MEMS die to a carrier substrate;

encapsulating the first MEMS die, the second MEMS die, and the third MEMS die with a molding material, the molding material extending from the carrier substrate over the first MEMS die, the second MEMS die, and the third MEMS die; and

removing the carrier substrate.

12. The method of claim 11 further comprising before encapsulating the first MEMS die, the second MEMS die, and the third MEMS die with the molding material, testing the first MEMS die, the second MEMS die, and the third MEMS die.

13. The method of claim 11 further comprising:

forming an application-specific integrated circuit (ASIC) die having at least one active device; and

before encapsulating the first MEMS die, the second MEMS die, and the third MEMS die with the molding material, attaching the ASIC die to the carrier substrate, wherein encapsulating the first MEMS die, the second MEMS die, and the third MEMS die with the molding material further comprises encapsulating the ASIC die with the molding material.

14. The method of claim 11, wherein the first cavity has a first pressure, wherein the second cavity has a second pressure, the second pressure being different from the first pressure, and wherein the third cavity has a third pressure, the third pressure being different from the first pressure and the second pressure.

15. The method of claim 11 further comprising:

forming a set of metal studs in the molding material, each of the metal studs extending from at least one of the first MEMS die, the second MEMS die, and the third MEMS die to a first surface of the molding material;

forming redistribution lines (RDLs) over the first surface of the molding material and the first MEMS die, the second MEMS die, and the third MEMS die, the RDLs being coupled to the set of metal studs; and

forming a set of solder balls over and electrically coupled to the RDLs.

16. A microelectromechanical systems (MEMS) device comprising:

a first MEMS die having a first cavity, the first cavity having a first pressure;

a second MEMS die having a second cavity, the second cavity having a second pressure, the second pressure being different from the first pressure;

a molding material surrounding the first MEMS die and the second MEMS die, the molding material having a first surface over the first and the second MEMS dies;

a first set of electrical connectors in the molding material, each of the first set of electrical connectors coupling at least one of the first and the second MEMS dies to the first surface of the molding material; and

a second set of electrical connectors over the first surface of the molding material, each of the second set of electrical connectors being coupled to at least one of the first set of electrical connectors.

17. The MEMS device of claim 16 further comprising a third MEMS die having a third cavity, the third cavity having a third pressure, the third pressure being different from the first pressure and the second pressure, the molding material surrounding the third MEMS die with the first surface of the molding material being over the third MEMS die.

18. The MEMS device of claim 17, wherein the first MEMS die comprises an accelerometer, the second die comprises a gyroscope, and the third MEMS die comprises a pressure sensor.

19. The MEMS device of claim 16 further comprising an application-specific integrated circuit (ASIC) die, the ASIC die comprising an active device, the molding material surrounding the ASIC die with the first surface of the molding material being over the ASIC die.

20. The MEMS device of claim 19, wherein the first MEMS die, the second MEMS die, and the ASIC die each have surfaces substantially coplanar with a second surface of the molding material, the second surface being opposite of the first surface.