Stacked MEMS device

• US 7,928,584 B2
• Filed: 10/20/2009
• Issued: 04/19/2011
• Est. Priority Date: 12/21/2006
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Harney, Kieran P., Goggin, Raymond, O Suilleabhain, Liam, Murphy, Eva
• Primary Examiner(s): Dang; Phuc T
• Application Number:
  US12/582,183
• Publication Number:
  US 20100032268A1
• Time in Patent Office: 546 Days
• Field of Search: 257/778, 257/E21.613, 257/E29.324, 438/50, 438/52
• US Class Current: 257/778
• CPC Class Codes: B81B 2201/014 having a cantilever fixed on one side connected to one or more dimples
• CPC Class Codes: B81B 2207/015 the micromechanical device and the control or processing electronics being integrated on the same substrate
• CPC Class Codes: B81B 2207/017 Smart-MEMS not provided for in B81B2207/012 - B81B2207/015
• CPC Class Codes: B81B 7/007 Interconnections between the MEMS and external electrical signals
• 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 2203/032 Gluing
• CPC Class Codes: H01H 59/0009 making use of micromechanics
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A MEMS apparatus has a MEMS device sandwiched between a base and a circuit chip. The movable member of the MEMS device is attached at the side up against the circuit chip. The movable member may be mounted on a substrate of the MEMS device or formed directly on a passivation layer on the circuit chip. The circuit chip provides control signals to the MEMS device through wire bonds, vias through the MEMS device or a conductive path such as solder balls external to the MEMS device.

Claims

1. A MEMS device comprising:

a circuit chip having an application specific integrated circuit and a passivated surface;

a MEMS microstructure formed on the passivated surface of the circuit chip;

a cap over the MEMS microstructure;

a first conductive path providing electrical communication between the MEMS microstructure and an external surface of the cap; and

a second conductive path extending from the circuit chip out beyond the external surface of the cap.

2. The MEMS device of claim 1 wherein the MEMS microstructure is suspended from the plane of the passivated surface.

3. The MEMS device of claim 1 wherein the second conductive path extends through the cap.

4. The MEMS device of claim 1 wherein the second conductive path is external to the cap.

5. The MEMS device of claim 4 wherein the second conductive path comprises at least one solder bump extending from the circuit chip out beyond the external surface of the cap.

6. The MEMS device of claim 1 wherein the second conductive path supplies control signals from the circuit chip for controlling movement of the MEMS microstructure.

7. The MEMS device of claim 1 further comprising encapsulating material substantially completely covering the circuit chip and the cap.

8. The MEMS device of claim 1 wherein the MEMS microstructure is made of gold and wherein the first conductive path comprises a conductive material with a resistivity less than 0.01 ohm per square.

9. The MEMS device of claim 1 wherein the circuit chip and MEMS microstructure are arranged such that control signals pass directly from the circuit chip to the MEMS microstructure.

10. A MEMS apparatus comprising:

a base having electrical interconnects;

a circuit chip having an application specific integrated circuit and a passivated surface;

a MEMS microstructure formed on the passivated surface of the circuit chip;

a cap over the MEMS microstructure, the cap being secured to the base;

a first conductive path providing electrical communication between the base and the MEMS microstructure; and

a second conductive path providing electrical communication between the circuitry of the circuit chip and electrical interconnects of the base.

11. The MEMS apparatus of claim 10 wherein the MEMS microstructure is suspended from the plane of the passivated surface.

12. The MEMS apparatus of claim 10 wherein the second conductive path extends through the cap.

13. The MEMS apparatus of claim 10 wherein the second conductive path is external to the cap.

14. The MEMS apparatus of claim 13 wherein the second conductive path comprises at least one solder bump extending from the circuit chip to the base.

15. The MEMS apparatus of claim 10 wherein the second conductive path supplies control signals from the circuit chip through the at least one of the electrical interconnects of the base to control movement of the MEMS microstructure.

16. The MEMS apparatus of claim 10 further comprising encapsulating material substantially completely covering the circuit chip and the cap.

17. The MEMS apparatus of claim 10 wherein the MEMS microstructure is made of gold and wherein the first conductive path comprises a conductive material with a resistivity less than 0.01 ohm per square.

18. The MEMS apparatus of claim 10 wherein the circuit chip and MEMS microstructure are arranged such that control signals pass directly from the circuit chip to the MEMS microstructure.

19. A switch comprising:

a MEMS device having a cap side, a substrate side and a movable member, the movable member attached at the substrate side and enclosed within a chamber between the substrate side and the cap side; and

an application specific integrated circuit at the substrate side of the MEMS device for electrically controlling the movable member between an open position breaking an electrical connection to the substrate side and a closed position completing an electrical connection to the substrate side; and

a conductive flip chip connection attached externally to the cap side of the MEMS device.

20. The switch of claim 19 wherein the flip chip connection comprises at least one solder bump.

21. The switch of claim 19 wherein the circuit chip serves as the substrate side of the MEMS device and the movable member is formed on the circuit chip.

22. The switch of claim 19 wherein the circuit chip is arranged flat on the substrate side of the MEMS device such that control signals pass directly from the circuit chip to the MEMS device.

23. The switch of claim 19 wherein the MEMS device comprises vias of conductive material having a resistivity of less than 0.01 ohm per square and wherein the movable member is made of gold.

24. The switch of claim 19 further comprising a circuit chip containing the application specific integrated circuit and encapsulating material molded over both the circuit chip and the MEMS device to substantially completely cover the circuit chip and the MEMS device.