Stacked MEMS device

• US 7,642,657 B2
• Filed: 12/19/2007
• Issued: 01/05/2010
• Est. Priority Date: 12/21/2006
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Suilleabhain, Liam O, Harney, Kieran P., Goggin, Raymond, Murphy, Eva
• Primary Examiner(s): Dang; Phuc T
• Application Number:
  US11/960,271
• Publication Number:
  US 20080157339A1
• Time in Patent Office: 748 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 apparatus comprising:

a base having electrical interconnects;

a MEMS device having a cap side, a substrate side and a movable member, the movable member attached at and electrically connected through the substrate side and enclosed within a chamber between the substrate side and the cap side, the cap side being secured to the base; and

a circuit chip at the substrate side of the MEMS device for electrically controlling the movable member, the movable member being between the base and the circuit chip.

2. The MEMS apparatus of claim 1 wherein the MEMS device is flip-chip connected to the base.

3. The MEMS apparatus of claim 1 wherein wire bonds electrically connect the circuit chip to the base for carrying control signals from the circuit chip to the MEMS device.

4. The MEMS apparatus of claim 1 wherein the circuit chip serves as the substrate side of the MEMS device and the movable member is formed on the circuit chip.

5. The MEMS apparatus of claim 4 further comprising solder bumps electrically connecting the circuit chip to the base.

6. The MEMS apparatus of claim 1 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.

7. The MEMS apparatus of claim 4 further comprising electrically connecting the circuit chip to the base through vias in the MEMS device and solder bumps from the vias to the base.

8. The MEMS apparatus of claim 1 wherein the MEMS device is a switch and the movable member is made of gold.

9. The MEMS apparatus of claim 8 wherein the MEMS device comprises vias of conductive material.

10. The MEMS apparatus of claim 9 wherein the conductive material has a resistivity of less than 0.01 ohm per square.

11. The MEMS apparatus of claim 1 further comprising encapsulating material molded over both the circuit chip and the MEMS device to substantially completely cover the circuit chip and the MEMS device.

12. A MEMS switch comprising:

a MEMS device having a movable gold beam suspended from a semiconductor substrate and a semiconductor cap enclosing a chamber about the beam;

a plurality of conductive vias through the semiconductor cap;

a plurality of conductive bumps on the semiconductor cap, each in electrical connection with one of the vias; and

a circuit chip for electrically controlling movement of the movable gold beam between an open position breaking an electrical connection with the vias and a closed position completing an electrical connection with the vias, the circuit chip being secured parallel to and on the semiconductor substrate.

13. The MEMS switch of claim 12 further comprising a base having electrical interconnects, wherein the plurality of conductive bumps are mounted on the base.

14. The MEMS switch of claim 13 further comprising wire bonds from the circuit chip to the base for supplying control signals from the circuit chip through at least one of the electrical interconnects to the MEMS device.

15. The MEMS switch of claim 13 wherein the conductive vias have a resistivity of less than 0.01 ohm per square.

16. The MEMS switch of claim 12 further comprising a layer of seal glass securing the circuit chip to the semiconductor substrate.

17. A MEMS apparatus comprising:

a base having electrical interconnects;

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, the can side being secured to the base; and

a circuit chip 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, the movable member being between the base and the circuit chip.

18. The MEMS apparatus of claim 17 wherein the MEMS device is flip-chip connected to the base.

19. The MEMS apparatus of claim 17 wherein wire bonds electrically connect the circuit chip to the base for carrying control signals from the circuit chip to the MEMS device.

20. The MEMS apparatus of claim 17 wherein the circuit chip serves as the substrate side of the MEMS device and the movable member is formed on the circuit chip.

21. The MEMS apparatus of claim 20 further comprising solder bumps electrically connecting the circuit chip to the base.

22. The MEMS apparatus of claim 17 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 MEMS apparatus of claim 20 further comprising electrically connecting the circuit chip to the base through vias in the MEMS device and solder bumps from the vias to the base.

24. The MEMS apparatus of claim 17 wherein the MEMS device is a switch and the movable member is made of gold.

25. The MEMS apparatus of claim 24 wherein the MEMS device comprises vias of conductive material.

26. The MEMS apparatus of claim 25 wherein the conductive material has a resistivity of less than 0.01 ohm per square.

27. The MEMS apparatus of claim 17 further comprising encapsulating material molded over both the circuit chip and the MEMS device to substantially completely cover the circuit chip and the MEMS device.