Method of fabricating microstructures and devices made therefrom
First Claim
1. A method of fabricating a micromachined device, comprising:
- forming a composite thin film layer stack on a substrate, the composite thin film layer stack having a plurality of etch-resistant layers;
directionally etching a first portion of the composite thin film layer stack selectively masked by a first etch-resistant layer;
directionally etching a first portion of the substrate selectively masked by the first etch-resistant layer to define a first composite thin film microstructure;
isotropically etching a second portion of the substrate for a controlled period of time to remove substrate material from under the first composite thin film microstructure;
removing a portion of the first etch-resistant layer;
directionally etching a second portion of the composite thin film layer stack selectively masked by a second etch-resistant layer; and
directionally etching a third portion of the substrate selectively masked by the second etch-resistant layer to define a second microstructure, the second microstructure comprising a composite thin film layer stack portion and a substrate layer portion.
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Accused Products
Abstract
Methods of fabricating micromachined devices are disclosed, as are micromachined (MEMS) devices fabricated using such methods. According to one embodiment, the method includes forming a composite thin film layer stack on a substrate such that composite thin film layer stack comprises a plurality of etch-resistant layers, directionally etching a first portion of the composite thin film layer stack selectively masked by a first etch-resistant layer thereof, and directionally etching a first portion of the substrate selectively masked by the first etch-resistant layer. These steps may result in the formation of a composite thin film microstructure. The method further includes isotropically etching a second portion of the substrate for a controlled period of time to remove substrate material from under the composite thin film microstructure, removing a portion of the first etch-resistant layer and directionally etching a second portion of the composite thin film layer stack selectively masked by a second etch-resistant layer, and directionally etching a third portion of the substrate selectively masked by the second etch-resistant layer to define a second microstructure, the second microstructure comprising a composite thin film layer stack portion and a substrate layer portion. The method may include backside etching the substrate prior to directionally etching the first portion of the composite thin film layer stack and/or removing the composite thin film layer stack portion from the second microstructure after directionally etching the third portion of the substrate. The composite thin film layer stack may include a CMOS circuitry layer stack and the substrate may include single-crystal silicon (SCS).
53 Citations
22 Claims
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1. A method of fabricating a micromachined device, comprising:
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forming a composite thin film layer stack on a substrate, the composite thin film layer stack having a plurality of etch-resistant layers; directionally etching a first portion of the composite thin film layer stack selectively masked by a first etch-resistant layer; directionally etching a first portion of the substrate selectively masked by the first etch-resistant layer to define a first composite thin film microstructure; isotropically etching a second portion of the substrate for a controlled period of time to remove substrate material from under the first composite thin film microstructure; removing a portion of the first etch-resistant layer; directionally etching a second portion of the composite thin film layer stack selectively masked by a second etch-resistant layer; and directionally etching a third portion of the substrate selectively masked by the second etch-resistant layer to define a second microstructure, the second microstructure comprising a composite thin film layer stack portion and a substrate layer portion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of fabricating a micromachined device, comprising:
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forming a CMOS circuitry layer stack on a SCS substrate, the CMOS circuitry layer stack having a plurality of metal etch-resistant layers; directionally etching a first portion of the CMOS circuitry layer stack selectively masked by a first metal etch-resistant layer; directionally etching a first portion of the SCS substrate selectively masked by the first metal etch-resistant layer; isotropically etching a second portion of the SCS substrate for a controlled period of time to remove substrate material from under a first composite CMOS thin film microstructure; removing a portion of the first metal etch-resistant layer; directionally etching a second portion of the CMOS circuitry layer stack selectively masked by a second metal etch-resistant layer; and directionally etching a third portion of the SCS substrate selectively masked by the second metal etch-resistant layer to define a second microstructure, the second microstructure comprising a composite CMOS thin film layer stack portion and a SCS substrate layer portion. - View Dependent Claims (16, 17, 18, 19)
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20. A method of fabricating a micromachined device, comprising:
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forming a composite thin film layer stack on a substrate, the circuitry layer including a plurality of etch-resistant layers; backside etching the substrate; removing a first portion of the composite thin film layer stack selectively masked by a first etch-resistant layer; directionally etching a portion of the substrate selectively masked by a second etch-resistant layer to define a microstructure, the microstructure comprising a composite thin film layer stack portion and a substrate layer portion; and removing the composite thin film layer stack portion from the microstructure by; removing a portion of a second etch-resistant layer; and directionally etching a second portion of the composite thin film layer stack. - View Dependent Claims (21, 22)
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Specification