MEMS switches with reduced switching voltage and methods of manufacture

• US 9,019,049 B2
• Filed: 03/14/2013
• Issued: 04/28/2015
• Est. Priority Date: 04/22/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Luce, Stephen E., Stamper, Anthony K.
• Primary Examiner(s): Talpalatski, Alexander
• Application Number:
  US13/826,070
• Publication Number:
  US 20130192964A1
• Time in Patent Office: 775 Days
• Field of Search: 335/78
• US Class Current: 335/78
• 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 1/00166 Electrodes
• CPC Class Codes: B81C 1/00523 Etching material
• CPC Class Codes: B81C 1/00698 Electrical characteristics, e.g. by doping materials
• CPC Class Codes: B81C 2201/0132 Dry etching, i.e. plasma etching, barrel etching, reactive ion etching [RIE], sputter etching or ion milling
• CPC Class Codes: B81C 2201/0133 Wet etching
• CPC Class Codes: B81C 2201/0135 Controlling etch progression
• CPC Class Codes: B81C 2201/0145 Spark erosion
• CPC Class Codes: B81C 2201/0154 other processes for film patterning not provided for in B81C2201/0149 - B81C2201/015
• CPC Class Codes: B81C 2203/0145 Hermetically sealing an opening in the lid
• 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 1/58 Electric connections to or between contacts; Terminals for high tension switches H01H33/025; for electromagnetic relays H01H50/14; for circuit breakers H01H71/08
• CPC Class Codes: H01H 1/66 Contacts sealed in an evacuated or gas-filled envelope, e.g. magnetic dry-reed contacts
• CPC Class Codes: H01H 11/00 Apparatus or processes specially adapted for the manufacture of electric switches processes specially adapted for manufacture of rectilinearly movable switches having a plurality of operating members associated with different sets of contacts, e.g. keyboards, H01H13/88
• CPC Class Codes: H01H 2059/0018 Special provisions for avoiding charge trapping, e.g. insulation layer between actuating electrodes being permanently polarised by charge trapping so that actuating or release voltage is altered
• CPC Class Codes: H01H 49/00 Apparatus or processes specially adapted to the manufacture of relays or parts thereof
• CPC Class Codes: H01H 50/005 using micromechanics
• CPC Class Codes: H01H 59/00 Electrostatic relays; Electro-adhesion relays
• CPC Class Codes: H01H 59/0009 making use of micromechanics
• CPC Class Codes: Y10T 29/49105 Switch making

Abstract

MEMS switches and methods of manufacturing MEMS switches is provided. The MEMS switch having at least two cantilevered electrodes having ends which overlap and which are structured and operable to contact one another upon an application of a voltage by at least one fixed electrode.

Claims

1. A structure comprising:

at least two fixed electrodes including a first fixed electrode and a second fixed electrode; and

at least two cantilevered electrodes of different lengths having ends which overlap,

wherein;

a first cantilevered electrode of the at least two cantilevered electrodes is a first length such that an arm of the first cantilevered electrode of the at least two cantilevered electrodes extends horizontally over the at least two fixed electrodes;

a second cantilevered electrode of the at least two cantilevered electrodes is a second length such that an arm of the second cantilevered electrode of the at least two cantilevered electrodes extends horizontally over only one of the at least two fixed electrodes and overlaps a portion the first cantilevered electrode of the at least two cantilevered electrodes, wherein the arm of the first cantilevered electrode is longer than the arm of the second cantilevered electrode;

bases of the at least two cantilevered electrodes and the at least two fixed electrodes are formed directly on surface of a dielectric layer;

an end of the first cantilevered electrode extends toward a base of the second cantilevered electrode;

an end of the second cantilevered electrode extends toward a base of the first cantilevered electrode; and

the first of the at least two cantilevered electrodes is structured and configured to contact the second fixed electrode upon an application of a voltage by at least the first fixed electrode.

2. The structure of claim 1, further comprising a hermetically sealed volume having encapsulated therein the at least two cantilevered electrodes and the at least two fixed electrodes, wherein the hermetically sealed volume is provided by at least a liner.

3. The structure of claim 2, wherein:

the first cantilevered electrode of the at least two cantilevered electrodes is a moveable electrode;

the second cantilevered electrode of the at least two cantilevered electrodes is a stationary electrode; and

the stationary electrode is fixed to the liner such that the stationary electrode remains stationary upon the application of the voltage by at least the first fixed electrode.

4. The structure of claim 3, wherein:

the voltage provided by the first fixed electrode is a positive voltage;

the stationary electrode is structured and configured to apply a negative voltage;

the moveable electrode is positioned between the second fixed electrode and the stationary electrode; and

the moveable electrode is structured and configured to move away from the stationary electrode and toward the first fixed electrode and to contact with the second fixed electrode upon the application of the positive voltage and the negative voltage.

5. The structure of claim 3, wherein the first fixed electrode and the second fixed electrode are aligned vertically under the moveable electrode.

6. The structure of claim 5, wherein the second fixed electrode is aligned vertically under the stationary electrode.

7. The structure of claim 3, wherein the liner of the hermetically sealed volume is a nitride layer.

8. The structure of claim 7, wherein the nitride layer is formed directly on an upper surface of the stationary electrode.

9. The structure of claim 1, wherein:

the first cantilevered electrode of the at least two cantilevered electrodes is a moveable electrode;

the second cantilevered electrode of the at least two cantilevered electrodes is a stationary electrode; and

the stationary electrode is fixed to the liner such that the stationary electrode remains stationary upon the application of the voltage by at least the first fixed electrode;

the first fixed electrode is only aligned vertically under the moveable electrode;

the second fixed electrode is aligned vertically under the stationary electrode and the moveable electrode; and

the liner of the hermetically sealed volume is a nitride layer.

10. The structure of claim 1, wherein arms of the at least two cantilever electrodes are free floating.

11. The structure of claim 1, wherein the first fixed electrode and the second fixed electrode are vertically aligned under an arm of the first cantilever electrode of the at least two cantilever electrodes.

12. The structure of claim 11, wherein:

the second fixed electrode is vertically aligned under an arm of the second cantilever electrode of the at least two cantilever electrodes; and

the first cantilever electrode is spaced within a cavity between the second cantilever electrode and the second fixed electrode.

13. The structure of claim 9, wherein the end of the stationary electrode is unattached to the liner.

14. The structure of claim 1, further comprising a plurality of metal filled vias extending vertically into the dielectric layer, wherein the bases of the at least two cantilevered electrodes and the at least two fixed electrodes contact the plurality of metal filled vias.