Micro-machined structure production using encapsulation
AssigneePalo Alto Research Center Incorporated
InventorsThomas Hantschel, Sven Kosgalwies, Eugene M. Chow, Gordon Todd Jagerson, Jr.
Life of this patent
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Abstract
Micro-machined (e.g., stress-engineered spring) structures are produced by forming a release layer, forming a partially or fully encapsulated beam/spring structure, and then releasing the beam/spring structure by etching the release layer. The encapsulation structure protects the beam/spring during release, so both the release layer and the beam/spring can be formed using plating and/or using the same material. The encapsulation structure can be metal, resist, polymer, oxide, or nitride, and may be removed after the release process, or retained as part of the completed micro-machined structure.
Claims10
A method for producing a micro-machined structure including a supported beam mounted on a substrate such that an air gap is defined between the substrate and the beam, the method comprising:
- forming a release layer over the substrate;
- patterning the release layer to define a wedge-shaped release structure including a diagonal surface extending from the substrate to a horizontal upper surface;
- forming the beam over the wedge-shaped release structure such that the beam includes side edges extending upward from the substrate and an upper surface facing away from the substrate;
- forming an encapsulation structure on at least the side edges of the beam such that encapsulation material forming said encapsulation structure extends from the release structure to the upper surface of the beam, whereby said encapsulation structure entirely covers the side edges of the beam, wherein said encapsulation structure comprises an encapsulation material plated onto the beam;
- and
- removing the wedge-shaped release structure located under the beam using an etchant selected such that the encapsulation structure prevents etching of at least the side edges of the beam, whereby an air gap is formed between the beam and the substrate.
A method for producing a micro-machined structure including a supported beam mounted on a substrate such that an air gap is defined between the substrate and the beam, the method comprising:
- forming a release layer over the substrate;
- patterning the release layer to define a wedge-shaped release structure including a diagonal surface extending from the substrate to a horizontal upper surface;
- forming the beam over the wedge-shaped release structure such that the beam includes side edges extending upward from the substrate and an upper surface facing away from the substrate;
- forming an encapsulation structure on at least the side edges of the beam;
- and
- removing the wedge-shaped release structure located under the beam using an etchant selected such that the encapsulation structure prevents etching of at least the side edges of the beam, whereby an air gap is formed between the beam and the substrate,
- wherein forming the release layer comprises depositing a selected material to form the release layer, and forming the beam comprises depositing the selected material over the release layer, and
- wherein depositing the selected material during both formation of the release layer and during formation of the beam comprises at least one of electroplating and electroless plating the selected material over the substrate.
A method for producing a micro-machined structure including a supported beam mounted on a substrate such that an air gap is defined between the substrate and the beam, the method comprising:
- forming a release layer over the substrate;
- patterning the release layer to define a wedge-shaped release structure including a diagonal surface extending from the substrate to a horizontal upper surface;
- forming the beam over the wedge-shaped release structure such that the beam includes side edges extending upward from the substrate and an upper surface facing away from the substrate;
- forming an encapsulation structure on at least the side edges of the beam;
- and
- removing the wedge-shaped release structure located under the beam using an etchant selected such that the encapsulation structure prevents etching of at least the side edges of the beam, whereby an air gap is formed between the beam and the substrate,
- wherein forming the release layer comprises depositing a selected material to form the release layer, and forming the beam comprises depositing the selected material over the release layer, and
- wherein depositing the selected material during both formation of the release layer and during formation of the beam comprises sputtering the selected material over the substrate.
Dependencies are inferred from the claim text.