US 7,977,137 B1Granted

Latching zip-mode actuated mono wafer MEMS switch method

AssigneeThe United States of America as represented by the Secretary of the Air Force

InventorsJohn L. Ebel, Rebecca Cortez, Kevin D. Leedy, Richard E. Strawser

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Abstract

A process for making a latching zip-mode actuated mono wafer MEMS switch especially suited to capacitance coupled signal switching of microwave radio frequency signals is disclosed. The single wafer fabrication process used for the switch employs sacrificial layers and liquid removal of these layers in order to also provide needed permanent physical protection for an ultra fragile switch moving arm member. Latched operation of the achieved MEMS switch without use of conventional holding electrodes or magnetic fields is also achieved. Fabrication of a single MEMS switch is disclosed however large or small arrays may be achieved. A liquid removal based fabrication process is disclosed.

Claims18

Dependent claims

A method of making a zip-mode actuated, mono wafer self-latching MEMS electrical switch comprising the steps of:

placing a fixed position metal electrical contact and coplanar surrounding metal on an electrically insulating substrate member;
forming a first layer of electrical charge retention-capable dielectric material over said fixed position metal electrical contact;
overlaying said layer of electrical charge retention-capable dielectric material, and said fixed position metal electrical contact with a first layer of sacrificial material;
providing a low spring constant, elongated, flexible, thin, cantilever, metallic switch wiper member over said first layer of sacrificial material and a selected portion of said electrically insulating substrate member, a free end of said wiper member residing contiguous said fixed position metal electrical contact;
covering said metallic switch wiper member, said first layer of sacrificial material, said first layer of electrical charge retention-capable dielectric material, said selected portion of said electrically insulating substrate member with a second shaped mass of said sacrificial organic material;
adding a second layer of said electrical charge retention-capable dielectric material over said second shaped mass of sacrificial organic material;
supplying a sealable metallic cap member over all of said second layer of electrical charge retention-capable dielectric material, said second shaped mass of said sacrificial organic material, said metallic switch wipe member, said first layer of sacrificial organic material, said first layer of electrical charge retention-capable dielectric material and said selected portion of said electrically insulating substrate member;
and
releasing said metallic switch wiper member from captivity in said sacrificial organic material in a releasing sequence accomplished within switch wiper member protecting confines for said sealable metallic cap member;
whereby said released switch wiper member is susceptible to receiving an opposing curvature s-shaped stable profile contour in at least one of a said electrical contact adjacent and a said sealable cap layer adjacent transiently energized switch wiper member operating positions.

7 more elements

An integrated circuit process compatible method of making a zip-mode actuated, mono wafer MEMS electrical switch, said method comprising the steps, of:

assembling multiple sub layers of said switch on an insulating substrate member, said sub layers including an exposed first sacrificial layer;
fabricating a fragile, thin film, low spring constant, movable switch wiper arm member of said switch on said first sacrificial layer;
covering said movable switch wiper arm and said multiple sub layers with a second sacrificial layer to form a stack assembly;
overlaying said stack assembly with an enclosing perforated shield member;
removing said sacrificial layers from said stack assembly via perforations in said perforated shield member and a liquid removal sequence;
said removing step releasing said fragile, thin film, low spring constant, movable switch wiper arm member from sacrificial layer captivity within protective confines of said enclosing perforated shield member;
and
sealing said shield member perforations with an externally applied material;
whereby said released, fragile, thin film, low spring constant, movable switch wiper arm member is susceptible to S shaped profile, zip mode, actuation by control electrodes attending said multiple sub layers and said enclosing perforated shield member.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/152,130Filed 8 May 2008 · continuation in part
Priority: 24 May 2004
Granted: 12 Jul 2011
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

H01H 59/0009
Electrostatic relays; Electro-adhesion relays: making use of micromechanics
B81B 7/0064
Packages or encapsulation: for protecting against electromagnetic or electrostatic interferences
B81B 2201/014
Characterised by the shape: having a cantilever fixed on one side connected to one or more dimples
B81B 2201/018
Characterised by the shape: switches not provided for in B81B2201/014 - B81B2201/016

Family

Application60/573,892Us provisional application · filed 24 May 2004
Application10/901,315Parent of this continuation-in-part · filed 27 Jul 2004
Application60/930,357Us provisional application · filed 11 May 2007
US 7,381,583 B1Parent of this continuation-in-part
US 7,977,137 B1This patent

From the US filing history. Foreign family members aren’t listed.