Methods of manufacture for MEMS switches with reduced switching voltage

Patent metadata

Field	Value
Publication number	US-10647569-B2
Application number	US-201715717187-A
Country	US
Kind code	B2
Filing date	Sep 27, 2017
Priority date	Apr 22, 2008
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

An approach includes a method of fabricating a switch. The approach includes forming a first cantilevered electrode over a first fixed electrode, forming a second cantilevered electrode with an end that overlaps the first cantilevered electrode, forming a third cantilevered electrode operable to directly contact the first cantilevered electrode upon an application of a voltage to a 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 cantilevered electrode over a first fixed electrode;
forming a second cantilevered electrode with an end that overlaps the first cantilevered electrode;
forming a third cantilevered electrode operable to directly contact the first cantilever electrode upon an application of a voltage to a 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;
removing the sacrificial resist; and
closing the at least one hole by deposition of additional liner material, and

wherein a material which forms the hermetically sealed volume comprises nitride.

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 first cantilevered electrode and 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 positive voltage is about 30 volts.

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

10. The method of claim 1 , further comprising forming an extending protrusion which extends upward from an upper surface of an arm of the first cantilevered electrode.

11. The method of claim 1 , wherein a height of the second fixed electrode is higher than a height of the first fixed electrode.

Assignees

• IBM

Inventors

• Luce Stephen E
• Stamper Anthony K

Classifications

• H01H50/005

  using micromechanics · CPC title

• H01H49/00

  Apparatus or processes specially adapted to the manufacture of relays or parts thereof · CPC title

• H01H59/00

  Electrostatic relays; Electro-adhesion relays · CPC title

• Y10T29/49105

  Switch making · CPC title

• H01H2059/0018

  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 title