Chemical etching of a semiconductive wafer by undercutting an etch stopped layer
First Claim
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1. In a method for making three-dimensional structures by chemical etching of a semiconductive wafer, the steps of:
- providing a pair of etch stopped layers on opposite major faces of a semiconductive wafer of semiconductive material;
introducing an etchant through openings in both of said etch stopped layers;
etching the substrate semiconductor through said openings in both etch stopped layers to undercut substantial portions of both of said etch stopped layers;
terminating the etch of substrate material so as to leave undercut structure in both of said etch stopped layers interconnected by interconnecting substrate semiconductive material whereby a three-dimensional structure is made; and
patterning the openings of said etch stopped layers to define a frame structure and cantilever beam portions of said etch stopped layers on both sides of said wafer, said cantilever beam portions being undercut by said etchant when the etch is terminated, one end of the undercut cantilever beam portions being supported from the frame structure and the other ends being supported from said interconnecting substrate material which is free to move relative to said frame structure by bending of the undercut cantilever beam portions.
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Abstract
Three dimensional single crystalline structures, such as folded cantilever beams supported from a frame and supporting a central structure free to move relative to the frame, are fabricated by anisotropically etching through openings in etch stop layers on opposite sides of the substrate wafer. The openings are patterned and aligned so that the etch stop layers are undercut to define etch stop portions interconnected by unetched substrate material.
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Citations
10 Claims
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1. In a method for making three-dimensional structures by chemical etching of a semiconductive wafer, the steps of:
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providing a pair of etch stopped layers on opposite major faces of a semiconductive wafer of semiconductive material; introducing an etchant through openings in both of said etch stopped layers; etching the substrate semiconductor through said openings in both etch stopped layers to undercut substantial portions of both of said etch stopped layers; terminating the etch of substrate material so as to leave undercut structure in both of said etch stopped layers interconnected by interconnecting substrate semiconductive material whereby a three-dimensional structure is made; and patterning the openings of said etch stopped layers to define a frame structure and cantilever beam portions of said etch stopped layers on both sides of said wafer, said cantilever beam portions being undercut by said etchant when the etch is terminated, one end of the undercut cantilever beam portions being supported from the frame structure and the other ends being supported from said interconnecting substrate material which is free to move relative to said frame structure by bending of the undercut cantilever beam portions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification