Micro-machining minute hollow using native oxide membrane
First Claim
1. A method of forming a hollow comprising the steps of:
- (a) forming a film having a number of holes at least on a partial area of a surface of a substrate, said film being formed to pass an etchant therethrough;
(b) etching said substrate by said etchant through the holes in at least a partial region of said film to form a hollow under at least said partial region of said film; and
(c) forming an upper layer at least on said film by film deposition to cover and close the holes and seal the hollow, wherein said upper layer does not contact a bottom surface of said hollow.
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Accused Products
Abstract
A native oxide film is formed on the surface of a silicon substrate. The native oxide film has at least island-shaped imperfect SiO2 regions not formed with a perfect SiO2 film. Before the native oxide film is formed, a mask layer having a necessary opening is formed over the silicon substrate, according to necessity. The silicon substrate is etched in a vapor phase via the imperfect SiO2 regions of the native oxide film to form a hollow under the native oxide film at least at a partial region thereof. An upper film is formed on the native oxide film to cover and close the imperfect SiO2 regions. In this manner, a minute hollow can be formed in the silicon substrate with good controllability.
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Citations
23 Claims
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1. A method of forming a hollow comprising the steps of:
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(a) forming a film having a number of holes at least on a partial area of a surface of a substrate, said film being formed to pass an etchant therethrough; (b) etching said substrate by said etchant through the holes in at least a partial region of said film to form a hollow under at least said partial region of said film; and (c) forming an upper layer at least on said film by film deposition to cover and close the holes and seal the hollow, wherein said upper layer does not contact a bottom surface of said hollow. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of forming a hollow comprising the steps of:
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(a) forming a convex region of a pattern on an underlying substrate having a surface , said convex region having a side wall generally perpendicular to the surface of said underlying substrate; (b) forming a side wall protection film on the side wall of said convex region; (c) forming a second film having a number of holes on the upper surface of said convex region, wherein said substrate surface and said side wall protection film have a higher resistance to etching by an etchant than the convex region; (d) removing at least a partial region of said convex region by said etchant through the holes; and (e) forming an upper film at least on said second film to cover the holes. - View Dependent Claims (17, 18, 19, 20)
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21. A method of forming a hollow comprising the steps of:
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forming an intermediate film on an underlying substrate; forming an upper film on said intermediate film, said upper film having etching selectively different from said intermediate film; selectively etching said upper film and said intermediate film at a region, wherein said underlying substrate has a higher resistance to this selective etching than said upper film and said intermediate film; forming a third film having a number of holes on a side wall of said intermediate film at said region, said third film having etching characteristic different from said intermediate film, said holes being capable of passing an etchant therethrough and of being closed by film deposition; etching said intermediate film by said etchant through holes of said third film to a depth; and forming a cover film at least on said third film to close the holes. - View Dependent Claims (22, 23)
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Specification