Method of trench isolation during the formation of a semiconductor device
First Claim
1. A method for forming an isolation device comprising the following steps:
- providing a semiconductor substrate having a surface;
patterning said substrate to expose wide areas and narrow areas of said substrate surface, said areas having a width less than said wide areas;
forming at least one wide recess and at least one narrow recess in said substrate;
forming a conformal film in said wide recess and in said narrow recess;
isotropically etching essentially all of said conformal film from said wide recess and leaving a portion of said conformal film in said narrow recess; and
forming an insulation from said substrate of said wide recess and from said portion of said conformal film in said narrow recess.
2 Assignments
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Accused Products
Abstract
A process for fabricating a recessed field oxide area comprises providing a substrate having isolation stacks and first and second recesses having openings therein, the first recesses being wider than the second recesses. The recesses can have a depth in the approximate range of 200Å-3000Å. Next, the first and second recesses are lined with nitride, and the substrate is blanketed with a conformal material which bridges the openings of the second recesses but not the openings of the first recesses. The conformal material and the nitride is removed from horizontal surfaces of the isolation stacks, and essentially all of the conformal material is removed from the first recesses. At least a portion of the conformal material is left in the second recesses. Subsequent to the step of removing the conformal material, the substrate and the conformal material is oxidized to create field oxide areas at the first and second recesses.
21 Citations
26 Claims
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1. A method for forming an isolation device comprising the following steps:
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providing a semiconductor substrate having a surface; patterning said substrate to expose wide areas and narrow areas of said substrate surface, said areas having a width less than said wide areas; forming at least one wide recess and at least one narrow recess in said substrate; forming a conformal film in said wide recess and in said narrow recess; isotropically etching essentially all of said conformal film from said wide recess and leaving a portion of said conformal film in said narrow recess; and forming an insulation from said substrate of said wide recess and from said portion of said conformal film in said narrow recess. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A process for isolating active areas of a semiconductor device, comprising the following steps:
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creating first and second recesses in a substrate, said first recess being wider than said second recess; forming a conformal film in said first and second recesses, said conformal film impinging on itself in said second recess and said conformal film not impinging on itself in said first recess; removing said conformal film such that a portion of said conformal film remains in said second recess and such that all of said conformal film is removed from said first recess; and forming an insulator from said conformal film which remains in said second recess after said step of removing said conformal film. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A process for fabricating a recessed field oxide area, comprising the following steps:
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providing a substrate having isolation stacks and first and second recesses having openings therein, said first recesses being wider than said second recesses; lining said first and second recesses with an oxidation-resistant material; blanketing said substrate with a conformal material, said conformal material bridging said openings of said second recesses; removing said conformal material and said oxidation-resistant material from horizontal surfaces of said isolation stacks, removing essentially all said conformal material from said first recesses, and leaving at least a portion of said conformal material in said second recesses; and subsequent to said step of removing said conformal material, oxidizing said substrate and said conformal material, thereby creating field oxide areas at said first and second recesses. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A method used during the formation of a semiconductor device comprising the following steps:
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creating first and second recesses in a substrate, said first recess being wider than said second recess; forming a conformal film in said first and second recesses, said conformal film impinging on itself in said second recess and said conformal film not impinging on itself in said first recess; isotropically etching said conformal film such that a portion of said conformal film remains in said second recess and such that essentially all of said conformal film is removed from said first recess; and forming an insulator from said conformal film which remains in said second recess after said step of removing said conformal film. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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Specification