MEMS swtich with internal conductive path

• US 9,583,294 B2
• Filed: 05/15/2014
• Issued: 02/28/2017
• Est. Priority Date: 04/25/2014
• Status: Active Grant

• Current Assignee: Analog Devices International Unlimited Company (Analog Devices, Inc.)
• Original Assignee: Analog Devices Global Unlimited Company (Analog Devices, Inc.)
• Inventors: Lee, Check F., Goggin, Raymond C., Fitzgerald, Padraig L., Stenson, Bernard P., Schirmer, Mark, Wong, Jo-ey
• Primary Examiner(s): Luebke, Renee
• Assistant Examiner(s): Jimenez, Anthony R.
• Application Number:
  US14/278,362
• Publication Number:
  US 20150311021A1
• Time in Patent Office: 1,020 Days
• Field of Search: 200/181, 200/239, 200/238, 200/600, 333/236, 333/239, 333/243, 333/244, 333/245, 333/248, 333/262, 148/1.5, 361/233, 361/278
• US Class Current: 1/1
• CPC Class Codes: B81B 2201/014 having a cantilever fixed on one side connected to one or more dimples
• CPC Class Codes: B81B 2207/092 Buried interconnects in the substrate or in the lid
• CPC Class Codes: B81B 7/007 Interconnections between the MEMS and external electrical signals
• CPC Class Codes: B81C 1/00341 Processes for manufacturing microsystems not provided for in groups B81C1/00023 - B81C1/00261
• CPC Class Codes: H01H 1/0036 Switches making use of microelectromechanical systems [MEMS] for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009
• CPC Class Codes: H01H 2001/0084 with perpendicular movement of the movable contact relative to the substrate
• CPC Class Codes: H01H 59/0009 making use of micromechanics

Abstract

A MEMS switch has a base formed from a substrate with a top surface and an insulator layer formed on at least a portion of the top surface. Bonding material secures a cap to the base to form an interior chamber. The cap effectively forms an exterior region of the base that is exterior to the interior chamber. The MEMS switch also has a movable member (in the interior chamber) having a member contact portion, an internal contact (also in the interior chamber), and an exterior contact at the exterior region of the base. The contact portion of the movable member is configured to alternatively contact the interior contact. A conductor at least partially within the insulator layer electrically connects the interior contact and the exterior contact. The conductor is spaced from and electrically isolated from the bonding material securing the cap to the base.

Claims

1. A MEMS switch comprising:

a substrate having a top surface;

an insulator layer on at least a portion of the top surface of the substrate, the insulator layer and substrate forming a base;

a cap;

bonding material securing the cap to the base to form an interior chamber, the cap forming an exterior region of the base that is exterior to the interior chamber;

a movable member having a member contact portion;

an interior contact, the member contact portion being configured to alternatively contact the interior contact, the movable member and interior contact being within the interior chamber;

an exterior contact at the exterior region of the base; and

a conductor at least partially within the insulator layer, the conductor electrically connecting the interior contact and the exterior contact, the conductor being spaced from and electrically isolated from the bonding material securing the cap to the base.

2. The MEMS switch as defined by claim 1 wherein the movable member comprises a cantilever.

3. The MEMS switch as defined by claim 1 wherein the bonding material comprises an electrically insulating material.

4. The MEMS switch as defined by claim 1 further comprising a conductive path extending from the conductor to the interior contact.

5. The MEMS switch as defined by claim 4 wherein the conductive path comprises a plurality of spaced apart vias.

6. The MEMS switch as defined by claim 1 wherein the insulator layer is between the conductor and the bonding material, the insulator layer electrically isolating the conductor from the bonding material.

7. The MEMS switch as defined by claim 1 wherein the bonding material hermetically seals the interior chamber.

8. The MEMS switch as defined by claim 1 comprising an actuation electrode configured to electrostatically control movement of the movable member.

9. The MEMS switch as defined by claim 1 wherein the conductor has a generally planar portion extending generally parallel with the top surface of the substrate, the generally planar portion being within the insulator layer and spaced between about 0.5 to 3 microns from the interior chamber.

22. The MEMS switch as defined by claim 1 further comprising a hard conductive outer layer on the member contact portion.

23. The MEMS switch as defined by claim 1 wherein the interior contact comprises a two-level conductor having a first portion for contact with the member contact portion and a second portion electrically coupled to the first portion and to the conductor, the second portion having a lower resistance than the first portion.

24. The MEMS switch as defined by claim 23 wherein the second portion comprises a concave surface facing a point of contact by the member contact portion.

25. The MEMS switch as defined by claim 24 wherein tie concave surface has a curvature with a substantially constant radius.

26. The MEMS switch as defined by claim 24 wherein the concave surface has a curvature with a varying radius.

27. The MEMS switch as defined by claim 1 further comprising:

a second exterior contact at the exterior region of the base; and

a second conductor on or at least partially within the insulator layer, the second conductor electrically connecting the movable member and the second exterior contact, the second conductor being spaced from and electrically isolated from the bonding material securing the cap to the base.

28. The MEMS switch as defined by claim 27 further comprising a second conductive path extending from the second conductor to the movable member.

29. The MEMS switch as defined by claim 28, wherein tie second conductive path comprises a plurality of spaced apart vias.

30. The MEMS switch as defined by claim 28, wherein the movable member comprises a conductive element in contact with the second conductive path.

31. The MEMS switch as defined by claim 1 further comprising:

a third exterior contact at the exterior region of the base;

a control electrode under a portion of the movable member; and

a third conductor on or at least partially within the insulator layer, the third conductor electrically connecting the control electrode and the third exterior contact, the third conductor being spaced from and electrically isolated from the bonding material securing the cap to the base.

32. The MEMS switch as defined by claim 1 wherein the movable member comprises:

a plurality of cantilever arms; and

a common member coupled to the plurality of cantilever arms, the common member including the member contact portion.

33. The MEMS switch as defined by claim 32 wherein the common member includes a plurality of member contact portions.

34. The MEMS switch as defined by claim 33 further comprising a plurality of interior contacts, wherein each member contact portion of the plurality of member contact portions is configured to alternatively contact a respective interior contact of the plurality of interior contacts.

35. The MEMS switch as defined by claim 34 further comprising a plurality of a conductors at least partially within the insulator layer, each conductor of the plurality of conductors electrically connecting a respective interior contact to an exterior contact, the conductors being spaced from and electrically isolated from the bonding material securing the cap to the base.

10. A MEMS switch comprising:

a substrate having a top surface;

an insulator layer on at least a portion of the top surface of the substrate, the insulator layer and substrate forming a base;

a cap;

bonding material securing the cap to the base to form an interior chamber;

a movable member having a member contact portion;

an interior contact, the member contact portion being configured to alternatively contact the interior contact, the movable member and interior contact being within the interior chamber; and

a conductor at least partially within the insulator layer, the conductor having a generally planar portion and at least one via extending from the generally planar portion,

one or more of the at least one via(s) electrically contacting the interior contact, the generally planar portion being substantially completely encapsulated by the insulator layer and the one or more via(s), the insulator layer electrically isolating the generally planar portion from the bonding material.

11. The MEMS switch as defined by claim 10 wherein the generally planar portion is spaced between about 0.5 and 3.0 microns from the interior chamber.

12. The MEMS switch as defined by claim 10 wherein the bonding material comprises an insulator material or a conductive material.

13. The MEMS switch as defined by claim 10 wherein the cap is electrically isolated from the base.

14. The MEMS switch as defined by claim 10 wherein the movable member comprises a cantilever.

15. The MEMS switch as defined by claim 10 wherein the bonding material secures the cap with material formed on the top surface of the substrate.

16. The MEMS switch as defined by claim 10 wherein the cap forms an exterior region of the base that is exterior to the interior chamber, the exterior region having an exterior contact, the conductive member electrically connecting the exterior contact with the interior contact.

17. A method of producing a MEMS switch, the method comprising:

forming an insulator layer on a substrate to produce a base, the insulator layer containing a completely encapsulated interior conductor;

removing a portion of the insulator layer after forming the insulator layer, forming a channel to expose the interior conductor;

forming a conductive path through the channel to electrically connect with the interior conductor;

forming, on the base, a switch microstructure that is movable and configured to alternatively electrically connect with the interior conductor through the conductive path; and

using a bonding material to secure a cap to the base, the cap and base forming an interior chamber containing the switch microstructure, the interior conductor being spaced from and electrically isolated from the bonding material securing the cap to the base.

18. The method as defined by claim 17 further comprising forming an exterior contact on the base, the exterior contact being exterior to the interior chamber and electrically connected with the interior conductor.

19. The method as defined by claim 17 wherein the bonding material comprises seal glass.

20. The method as defined by claim 17 further comprising forming an internal contact that is electrically connected with the conductive path, the internal contact being formed from a metal material with the property of having a conductive oxide when oxidized.

21. The method as defined by claim 17 wherein forming the insulator layer comprises:

forming a conductor on a portion of a first insulator layer, and

depositing a second insulator layer on the first insulator layer and conductor to form the encapsulated interior conductor.