US5472539A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Methods for forming and positioning moldable permanent magnets on electromagnetically actuated microfabricated components
Assignee: General Electric Co
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Filing: 1994-06-06
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Granted: 1995-12-05
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Expires: 2014-06-06
Abstract
Abstract A low temperature batch method for forming and positioning permanent magnets on electromagnetically actuated micro-fabricated components, such as electrical switches employs a first adhesive, such as a Siltem/epoxy blend of an epoxy resin and a siloxane polyimide polymer, to releasably attach a mold layer of Kapton polyimide to a substrate, which may be the movable portion of a micromechanical structure, or a precursor to such movable portion. A well-shape cavity is formed in the mold layer, and filled with a slurry of rare earth NdFeB magnetic particles suspended in a second adhesive, which is cured to form the body of a magnet. The second adhesive is an SPI/epoxy blend, also of an epoxy resin and a siloxane polyimide polymer, but with a greater adhesion strength and a higher temperature softening point compared to the Siltem/epoxy blend. The entire structure is heated, and the mold layer is pulled off the substrate, while the body of magnetic material remains firmly attached. Selective etchants may be subsequently employed to remove metal sacrificial layers, while the NdFeB magnetic particles are protected from attack by the etchant by being effectively encased in plastic.
Inventors
- 👤 Richard J. Saia
- 👤 Kevin M. Durocher
- 👤 Thomas B. Gorczyca
- 👤 Mario Ghezzo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 06:37
CPC Classifications
H; H01; H01H; H01H50/00; H01H50/005; H02; H02K; H02K99/00; H01H2050/007
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
146 words
A method for fabricating an electromagnetically actuated micromechanical structure, comprising the steps of: fabricating a precursor to a micromechanical structure, the precursor including a base, an element subsequently to become moveable relative to the base, and a sacrificial layer separating the base and the element and supporting the base on the element; employing a first adhesive to releasably attach a mold layer of polymer material to the element; forming a well-shaped cavity extending through the mold layer of polymer material; filling the well-shaped cavity with a slurry of magnetic particles in a second adhesive; curing the second adhesive to form a body of magnetic material; removing the mold layer of polymer material and the first adhesive while allowing the body to remain adhered to the element; and releasing the element for movement relative to the base by employing a selective etch to remove the sacrificial layer.
Claim 2
Independent Claim
146 words
A method for fabricating an electromagnetically actuated micromechanical structure, comprising the steps of: fabricating a precursor to a micromechanical structure, the precursor including a base, an element subsequently to become moveable relative to the base, and a sacrificial layer separating the base and the element and supporting the base on the element; employing a first adhesive to releasably attach a mold layer of polymer material to the element; forming a well-shaped cavity extending through the mold layer of polymer material; filling the well-shaped cavity with a slurry of magnetic particles in a second adhesive; curing the second adhesive to form a body of magnetic material; removing the mold layer of polymer material and the first adhesive while allowing the body to remain adhered to the element; and releasing the element for movement relative to the base by employing a selective etch to remove the sacrificial layer.
Claim 3
Dependent Claim
40 words
The method of claim 1, wherein the first adhesive has a lower adhesion strength than the second adhesive when heated, and wherein the step of removing the mold layer of polymer material comprises heating the precursor, mold layer and adhesives.
Claim 4
Dependent Claim
14 words
The method of claim 2, which further comprises the step of magnetizing the body.
Claim 5
Dependent Claim
24 words
The method of claim 1, wherein the step of fabricating a precursor to a micromechanical structure comprises fabricating a precursor which includes an electromagnet.
Claim 6
Dependent Claim
28 words
The method of claim 1, wherein the step of fabricating a precursor to a micromechanical structure comprises fabricating a precursor wherein the element is an electrical switch contact.
Claim 7
Dependent Claim
21 words
The method of claim 1, wherein the first adhesive comprises a blend of an epoxy resin and a siloxane polyimide polymer.
Claim 8
Dependent Claim
21 words
The method of claim 1, wherein the second adhesive comprises a blend of an epoxy resin and a siloxane polyimide polymer.
Claim 9
Dependent Claim
22 words
The method of claim 6, wherein the second adhesive comprises a blend of said epoxy resin and a second siloxane polyimide polymer.
Claim 10
Dependent Claim
25 words
The method of claim 1, wherein the step of forming a well-shaped cavity comprises laser-ablating a predetermined portion of said mold layer of polymer material.
Claim 11
Dependent Claim
47 words
The method of claim 9, wherein the step of forming a well-shaped cavity comprises: providing a metal mask over the mold layer of polymer material, with an opening in the metal mask defining the cavity location; and ablating with a laser the polymer material where not masked.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-12-04 | 1999-06-05 | 1999-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-12-04 | 2003-06-05 | 2003-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-12-04 | 2007-06-05 | 2007-12-05 | $7700.00 | Window Closed / Lapsed |