MICRO ELECTROMECHANICAL SYSTEM SENSOR AND METHOD OF FORMING THE SAME

• US 20150175407A1
• Filed: 12/20/2013
• Published: 06/25/2015
• Est. Priority Date: 12/20/2013
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: CHENG, Chun-wen, TSAI, Hung-Chia, CHAO, Lan-Lin, HSIEH, Yuan-Chih, LIU, Ping-Yin
• Granted Patent: US 9,725,310 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81C 1/00246 Monolithic integration, i.e. micromechanical structure and electronic processing unit are integrated on the same substrate

Abstract

A micro electromechanical system (MEMS) device includes a MEMS section attached to a substrate, and a cap bonded to a first surface of the substrate. The MEMS device further includes a carrier bonded to a second surface of the substrate opposite the first surface, wherein the carrier is free of active devices, and the cap and the carrier define a vacuum region surrounding the MEMS section. The MEMS device further includes a bond pad on a surface of the carrier opposite the MEMS section, wherein the bond pad is electrically connected to the MEMS section.

Claims

1. A micro electromechanical system (MEMS) device comprising:

a MEMS section attached to a substrate;

a cap bonded to a first surface of the substrate;

a carrier bonded to a second surface of the substrate opposite the first surface, wherein the carrier is free of active devices, and the cap and the carrier define a vacuum region surrounding the MEMS section; and

a bond pad on a surface of the carrier opposite the MEMS section, wherein the bond pad is electrically connected to the MEMS section.

2. The MEMS device of claim 1, further comprising a conductive plug extending through the carrier, the conductive plug connected to the bond pad, wherein the conductive plug comprises tungsten.

3. The MEMS device of claim 1, further comprising an isolation trench extending through the carrier, the isolation trench surrounding the bond pad, wherein the bond pad is configured to receive a signal through the carrier between the isolation trench.

4. The MEMS device of claim 3, wherein a surface of the bond pad is level with a surface of the carrier.

5. The MEMS device of claim 1, further comprising an active circuit wafer, the active circuit wafer comprising:

an active circuit substrate comprising active devices; and

an interconnect structure configured to convey signals to and from the active devices, wherein the interconnect structure is boned to the surface of the carrier opposite the MEMS section at an interface, and the carrier is positioned to block outgassing from the interconnect structure from entering the vacuum region.

6. The MEMS device of claim 5, wherein the interconnect structure comprises an interconnect bond pad bonded to the bond pad, wherein grain boundaries between the interconnect bond pad and the bond pad extend across the interface.

7. The MEMS device of claim 1, wherein the cap comprises a first metal layer, the substrate comprises a second metal layer, and the first metal layer and the second metal layer are in a eutectic bond.

8. A micro electromechanical system (MEMS) package comprising:

a MEMS section attached to a substrate;

a cap bonded to a first surface of the substrate;

a carrier bonded to a second surface of the substrate opposite the first surface, wherein the carrier is free of active devices, and the cap and the carrier define a vacuum region surrounding the MEMS section;

a bond pad on a surface of the carrier opposite the MEMS section, wherein the bond pad is electrically connected to the MEMS section;

an active circuit wafer, the active circuit wafer comprising an active circuit substrate and an interconnect structure, the interconnect structure bonded to the surface of the carrier opposite the MEMS section at an interface, wherein the carrier is positioned to block outgassing from the interconnect structure from entering the vacuum region; and

a conductive element through the active circuit substrate, the conductive element configured to transfer a signal to external circuitry.

9. The MEMS package of claim 8, further comprising a conductive plug extending through the carrier, the conductive plug connected to the bond pad, wherein the conductive plug comprises tungsten.

10. The MEMS package of claim 8, further comprising an isolation trench extending through the carrier, the isolation trench surrounding the bond pad, wherein the bond pad is configured to receive a signal through the carrier between the isolation trench.

11. The MEMS package of claim 10, wherein a surface of the bond pad is level with a surface of the carrier.

12. The MEMS package of claim 8, wherein the conductive element comprises a tungsten plug.

13. The MEMS package of claim 8, wherein the conductive element comprises a through substrate via (TSV).

14. The MEMS package of claim 8, further comprising:

a re-distribution layer (RDL) electrically connected to the conductive element;

a polymer layer over the RDL; and

a solder ball in the polymer layer, the solder ball electrically connected to the RDL.

15. The MEMS package of claim 8, wherein the interconnect structure comprises an interconnect bond pad bonded to the bond pad, wherein grain boundaries between the interconnect bond pad and the bond pad extend across the interface.

16. The MEMS package of claim 8, wherein the cap comprises a first metal layer, the substrate comprises a second metal layer, and the first metal layer and the second metal layer are in a eutectic bond.

17. A method of making a micro electromechanical system (MEMS) package, the method comprising:

patterning a substrate to form a MEMS section;

bonding a cap to a first surface of the substrate;

bonding a carrier to a second surface of the substrate opposite the first surface, wherein the carrier is free of active devices, and the cap and the carrier define a vacuum region surrounding the MEMS section; and

forming a bond pad on a surface of the carrier opposite the MEMS section, wherein the bond pad is electrically connected to the MEMS section.

18. The method of claim 17, further comprising forming a conductive plug through the carrier, the conductive plug connected to the bond pad, wherein the conductive plug comprises tungsten.

19. The method of claim 17, further comprising forming an isolation trench extending through the carrier, the isolation trench surrounding the bond pad, wherein the bond pad is configured to receive a signal through the carrier between the isolation trench.

20. The method of claim 17, further comprising fusion bonding an active circuit wafer to the surface of the carrier opposite the MEMS section, the active circuit wafer comprising:

an active circuit substrate comprising active devices; and

an interconnect structure configured to convey signals to and from the active devices, wherein the interconnect structure is fusion boned to the surface of the carrier opposite the MEMS section.