Method of manufacture MEMS switches with reduced voltage

Patent metadata

Field	Value
Publication number	US-9944518-B2
Application number	US-201514883843-A
Country	US
Kind code	B2
Filing date	Oct 15, 2015
Priority date	Apr 22, 2008
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

An approach includes a method of fabricating a switch. The approach includes forming a first fixed electrode and a second fixed electrode, forming a first cantilevered electrode aligned vertically over the first fixed electrode, forming a second cantilevered electrode aligned vertically over the first fixed electrode and which has an end that overlaps the first cantilevered electrode, forming a third cantilevered electrode aligned vertically over the second fixed electrode and operable to directly contact the first cantilevered electrode upon an application of a voltage to the second fixed electrode, and forming a hermetically sealed volume encapsulating the first fixed electrode, the second fixed electrode, the first cantilevered electrode, and the second cantilevered electrode.

First claim

It is claimed:

1. A method of fabricating a switch comprising:
forming a first fixed electrode and a second fixed electrode;
forming a first cantilevered electrode aligned vertically over the first fixed electrode;
forming a second cantilevered electrode aligned vertically over the first fixed electrode, and which has an end that overlaps and is parallel to an end of the first cantilevered electrode;
forming a third cantilevered electrode aligned vertically over the second fixed electrode and operable to directly contact the first cantilever electrode upon an application of a positive voltage to the second fixed electrode;
forming an extending protrusion which extends upward from an upper surface of an arm of the first cantilever electrode which is positioned under the third cantilevered electrode; and
forming a hermetically sealed volume encapsulating the first fixed electrode, the second fixed electrode, the first cantilevered electrode, and the second cantilevered electrode.

2. The method of claim 1 , wherein the hermetically sealed volume is a dome.

3. The method of claim 2 , wherein the dome is oval shaped.

4. The method of claim 1 , wherein overlapping portions of the end of the first cantilevered electrode and the end of the second cantilevered electrode are separated by a vertical distance of about two microns.

5. The method of claim 1 , wherein the third cantilevered electrode is formed above the second cantilevered electrode.

6. The method of claim 1 , wherein the second cantilevered electrode is formed above the first cantilevered electrode.

7. The method of claim 1 , wherein the first cantilevered electrode is formed such that upon application of a negative voltage to the first fixed electrode and a positive voltage to the second cantilevered electrode, the first cantilevered electrode is operable to directly contact the third cantilevered electrode.

8. The method of claim 7 , wherein the negative voltage is about −30 volts and the positive voltage is about 30 volts.

9. The method of claim 1 , wherein the hermetically sealed volume comprises nitride.

10. The method of claim 1 , wherein the positive voltage is about 30 volts.

11. A method of fabricating a switch comprising:
forming a first fixed electrode and a second fixed electrode;
forming a first cantilevered electrode aligned vertically over the first fixed electrode;
forming a second cantilevered electrode aligned vertically over the first fixed electrode, and which has an end that overlaps the first cantilevered electrode;
forming a third cantilevered electrode aligned vertically over the second fixed electrode and operable to directly contact the first cantilever electrode upon an application of a voltage to the second fixed electrode; and
forming a hermetically sealed volume encapsulating the first fixed electrode, the second fixed electrode, the first cantilevered electrode, and the second cantilevered electrode,
wherein the forming the hermetically sealed volume comprises:
forming at least one hole in a nitride liner to gain access to a sacrificial resist;
etching the sacrificial resist; and
closing the at least one hole by deposition of additional liner material.

Assignees

• IBM

Inventors

• Luce Stephen E
• Stamper Anthony K

Classifications

• B81C1/00698 Primary

  Electrical characteristics, e.g. by doping materials · CPC title

• H01H1/0036

  Switches making use of microelectromechanical systems [MEMS] (for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009) · CPC title

• H01H59/0009 Primary

  making use of micromechanics · CPC title

• H01H1/58

  Electric connections to or between contacts; Terminals {(for high tension switches H01H33/025; for electromagnetic relays H01H50/14; for circuit breakers H01H71/08)} · CPC title

• B81C2201/0132

  Dry etching, i.e. plasma etching, barrel etching, reactive ion etching [RIE], sputter etching or ion milling · CPC title