Mechanically assisted restoring force support for micromachined membranes

• US 6,657,832 B2
• Filed: 04/26/2001
• Issued: 12/02/2003
• Est. Priority Date: 04/26/2001
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Ng, Laurinda W., Williams, Bryon L., Crenshaw, Darius L., Melendez, Jose L.
• Primary Examiner(s): Sircus, Brian
• Assistant Examiner(s): Demakis, James A
• Application Number:
  US09/843,395
• Publication Number:
  US 20020179421A1
• Time in Patent Office: 950 Days
• Field of Search: 361/15, 361/123, 200/181
• US Class Current: 361/15
• CPC Class Codes: H01G 5/16 using variation of distance between electrodes
• CPC Class Codes: H01H 2059/0072 with stoppers or protrusions for maintaining a gap, reducing the contact area or for preventing stiction between the movable and the fixed electrode in the attracted position
• CPC Class Codes: H01H 59/0009 making use of micromechanics

Abstract

The present invention includes an integrated circuit switch including a membrane supported over a first conductor on a substrate, a conductive region on the membrane and connecting to the first conductor on the substrate, a pulldown electrode on the substrate and under the membrane and a pillar to support the membrane after the pulldown threshold has been reached. A voltage greater than a pulldown threshold is applied between the membrane and the pulldown electrode will pull the membrane down to make a capacitive coupling to the first conductor. The addition of the pillars increases the upward restoring force when the activation voltage is removed.

Claims

1. An integrated circuit switch, comprising:

a membrane supported over a first conductor on a substrate;

a conductive region on said membrane and connecting to said first conductor on said substrate;

a pulldown electrode on said substrate and under said membrane; and

a pillar to support said membrane only after a pulldown threshold has been reached,

wherein a voltage greater than said pulldown threshold and applied between said membrane and said pulldown electrode will pull said membrane down to make a capacitive coupling to said first conductor,

wherein said integrated circuit switch included a dielectric and, said pillar has a height less than ⅔

the distance between the said membrane and said dielectric.

2. An integrated circuit switch as in claim 1, wherein said integrated circuit switch included a spacer under said membrane.

3. An integrated circuit switch as in claim 1, wherein said pillar is positioned between said dielectric and said spacer.

4. An integrated circuit switch as in claim 1, wherein said integrated circuit switch included a plurality of pillars arranged in an approximate circle.