Active opening MEMS switch device

• US 10,640,363 B2
• Filed: 02/02/2017
• Issued: 05/05/2020
• Est. Priority Date: 02/04/2016
• Status: Active Grant

• Current Assignee: Analog Devices International Unlimited Company (Analog Devices, Inc.)
• Original Assignee: Analog Devices, Inc.
• Inventors: Fitzgerald, Padraig, Twohig, Michael James
• Primary Examiner(s): Saeed, Ahmed M
• Application Number:
  US15/422,508
• Publication Number:
  US 20170225942A1
• Time in Patent Office: 1,188 Days
• Field of Search: 200181, 200600, 200 6145 R, 200243
• CPC Class Codes: B81B 2201/014 having a cantilever fixed on one side connected to one or more dimples
• CPC Class Codes: B81B 2203/0118 Cantilevers
• CPC Class Codes: B81B 2203/0181 See-saws
• CPC Class Codes: B81B 3/0051 For defining the movement, i.e. structures that guide or limit the movement of an element mechanical arrangements for preventing or damping vibration or shock H01H3/60
• CPC Class Codes: B81C 1/0015 Cantilevers switches using MEMS H01H1/0036; electrostatic relays using micromechanics H01H59/0009; microelectro-mechanical resonators H03H9/02244
• CPC Class Codes: B81C 2201/0109 Sacrificial layers not provided for in B81C2201/0107 - B81C2201/0108
• CPC Class Codes: B81C 2201/0197 Processes for making multi-layered devices not provided for in groups B81C2201/0176 - B81C2201/0192
• CPC Class Codes: H01H 2059/0027 Movable electrode connected to ground in the open position, for improving isolation
• CPC Class Codes: H01H 2059/0054 Rocking contacts or actuating members
• CPC Class Codes: H01H 59/0009 making use of micromechanics

Abstract

Microelectromechanical systems (MEMS) switches are described. The MEMS switches can be actively opened and closed. The switch can include a beam coupled to an anchor on a substrate by one or more hinges. The beam, the hinges and the anchor may be made of the same material in some configurations. The switch can include electrodes, disposed on a surface of the substrate, for electrically controlling the orientation of the beam. The hinges may be thinner than the beam, resulting in the hinges being more flexible than the beam. In some configurations, the hinges are located within an opening in the beam. The hinges may extend in the same direction of the axis of rotation of the beam and/or in a direction perpendicular to the axis of rotation of the beam.

Claims

1. A microelectromechanical systems (MEMS) switch, comprising:

a substrate;

a post on the substrate;

first, second, third and fourth electrodes disposed on the substrate, the first and second electrodes being positioned on a first side of the post, the third and fourth electrodes being positioned on a second side of the post that is opposite the first side;

a fifth electrode disposed on the substrate and in electrical communication with the post;

a microscale beam enclosing an opening in a center portion thereof, the post being disposed within the enclosed opening; and

a hinge disposed within the enclosed opening and mechanically coupling the beam to the post,

wherein the hinge has a first thickness and the beam comprises a conductive beam of a second thickness greater than the first thickness.

2. The MEMS switch of claim 1, wherein the conductive beam comprises first and second conductive layers.

3. The MEMS switch of claim 1, wherein the first thickness is less than half the second thickness.

4. The MEMS switch of claim 1, wherein the beam has a first end configured to make electrical contact with the substrate, a second end configured to make electrical contact with the substrate, and a length between the first end and the second end, and wherein the hinge has a length in a same direction as the length of the beam.

5. The MEMS switch of claim 1, wherein the beam has a first end configured to make electrical contact with the substrate, a second end configured to make electrical contact with the substrate, and a length between the first end and the second end, and wherein the hinge has a length in a direction perpendicular to the length of the beam.

6. The MEMS switch of claim 1, wherein the conductive beam and the hinge are formed of a same material.

7. The MEMS switch of claim 1, wherein:

the first electrode forms a first capacitor with the conductive beam, and the third electrode forms a second capacitor with the conductive beam, wherein the first and second capacitors are arranged for controlling orientation of the conductive beam,

the second electrode is positioned to contact a first portion of the conductive beam when the conductive beam is in a first orientation, wherein the second electrode forms part of a first conductive path comprising the first portion of the conductive beam, the post, and the fifth electrode when the conductive beam is in the first orientation, and

the fourth electrode is positioned to contact a second portion of the conductive beam when the conductive beam is in a second orientation different from the first orientation, wherein the fourth electrode forms part of a second conductive path comprising the second portion of the conductive beam, the post, and the fifth electrode when the conductive beam is in the second orientation.

8. A method of fabricating a microelectromechanical systems (MEMS) switch, comprising:

fabricating a post on a substrate;

fabricating a hinge coupled to the post;

fabricating first, second, third and fourth electrodes on the substrate, such that the first and second electrodes are positioned on a first side of the post and the third and fourth electrodes are positioned on a second side of the post that is opposite the first side;

fabricating a fifth electrode on the substrate and in electrical communication with the post; and

fabricating a beam enclosing an opening in a center portion thereof,

each of the post and the hinge being disposed within the enclosed opening, and the beam being coupled to the post via the hinge,

wherein fabricating the hinge and fabricating the beam comprises fabricating the hinge to have a first thickness and the beam to have a second thickness greater than the first thickness.

9. The method of claim 8, wherein fabricating the hinge and fabricating the beam comprises fabricating the hinge to have the first thickness less than half the second thickness.

10. The method of claim 8, wherein fabricating the hinge and fabricating the beam comprises fabricating a length of the hinge to be in a same direction as a length of the beam.

11. The method of claim 8, wherein fabricating the hinge and fabricating the beam comprises fabricating a length of the hinge to be substantially perpendicular to a length of the beam.

12. The method of claim 8, wherein fabricating the hinge and fabricating the beam comprises fabricating the hinge and the beam of a same material.

13. The method of claim 8, wherein fabricating the post, the hinge, and the beam involves performing fewer than three electroplating steps.

14. The method of claim 8, wherein fabricating the fifth electrode and fabricating the post comprise fabricating the fifth electrode to be between the post and the substrate.

15. A microelectromechanical systems (MEMS) switch, comprising:

a substrate;

a post on the substrate;

first, second, third and fourth electrodes disposed on the substrate, the first and second electrodes being positioned on a first side of the post, the third and fourth electrodes being positioned on a second side of the post that is opposite the first side;

a fifth electrode disposed on the substrate and in electrical communication with the post;

a microscale beam enclosing an opening in a center portion thereof, the post being disposed within the enclosed opening; and

means for coupling the beam to the post,

wherein the means has a first thickness and the beam comprises a conductive beam of a second thickness greater than the first thickness.

16. The MEMS switch of claim 15, wherein the conductive beam comprises first and second conductive layers.

17. The MEMS switch of claim 15, wherein the means is disposed within the enclosed opening.

18. The MEMS switch of claim 15, wherein the beam has a first end configured to make electrical contact with the substrate, a second end configured to make electrical contact with the substrate, and a length between the first end and the second end, and wherein the means has a length in a same direction as the length of the beam.

19. The MEMS switch of claim 15, wherein the beam has a first end configured to make electrical contact with the substrate, a second end configured to make electrical contact with the substrate, and a length between the first end and the second end, and wherein the means has a length in a direction perpendicular to the length of the beam.

20. The MEMS switch of claim 15, wherein:

the first electrode forms a first capacitor with the conductive beam, and the third electrode forms a second capacitor with the conductive beam, wherein the first and second capacitors are arranged for controlling orientation of the conductive beam,

the second electrode is positioned to contact a first portion of the conductive beam when the conductive beam is in a first orientation, wherein the second electrode forms part of a first conductive path comprising the first portion of the conductive beam, the post, and the fifth electrode when the conductive beam is in the first orientation, and

the fourth electrode is positioned to contact a second portion of the conductive beam when the conductive beam is in a second orientation different from the first orientation, wherein the fourth electrode forms part of a second conductive path comprising the second portion of the conductive beam, the post, and the fifth electrode when the conductive beam is in the second orientation.