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Patent US5438016A successfully refreshed from Google Patents.
US5438016A
Expired / Lapsed
US
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Method of semiconductor device isolation employing polysilicon layer for field oxide formation
Assignee: Micron Technology Inc
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Filing: 1994-03-02
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Granted: 1995-08-01
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Expires: 2014-03-02
Abstract
Abstract A process for forming field oxide on a semiconductor substrate having reduced field oxide thinning comprises forming an oxide layer over a semiconductor substrate, and forming a protective layer over the oxide layer. A mask is formed over the protective layer thereby forming exposed and covered regions of the protective layer. The exposed portions of the protective layer are removed to form at least first, second, and third disconnected protective structures, wherein the distance between the first and second protective structures is smaller than the distance between the second and third protective structures. The oxide layer and a portion of the substrate between the protective structures is removed to expose a portion of the substrate. A blanket polycrystalline silicon (poly) layer is formed over the substrate, and the poly layer is isotropically etched to remove the poly from between the second and third protective structures and to leave a portion of the poly between the first and second structures. The poly between the first and second protective structures is oxidized to form regions of field oxide having a substantially uniform thickness across the substrate. The oxidation between the first and second protective structures can also include substrate oxidation once the poly is consumed.
Inventors
- 👤 Thomas A. Figura
- 👤 Nanseng Jeng
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:36
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10W10/0121; H10W10/014; H10W10/0142; H10W10/041; H10W10/10; H10W10/13; H10W10/17; H10W10/40
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
144 words
A process for forming a semiconductor device, comprising the following steps: a) forming a patterned protective layer over a semiconductor substrate, said protective layer having at least first, second, and third disconnected protective structures such that a first distance between said first and second protective structures is narrower than a second distance between said second and third protective structures; b) removing a portion of said substrate between said protective structures thereby exposing portions of said substrate; c) forming a blanket polycrystalline silicon layer over said substrate; d) isotropically etching said polycrystalline silicon layer to remove said polycrystalline silicon from between said second and third protective structures and leaving a portion of said polycrystalline silicon between said first and second protective structures; e) oxidizing said substrate between said second and third protective structures and said polycrystalline silicon layer between said first and second protective structures.
Claim 2
Dependent Claim
144 words
A process for forming a semiconductor device, comprising the following steps: a) forming a patterned protective layer over a semiconductor substrate, said protective layer having at least first, second, and third disconnected protective structures such that a first distance between said first and second protective structures is narrower than a second distance between said second and third protective structures; b) removing a portion of said substrate between said protective structures thereby exposing portions of said substrate; c) forming a blanket polycrystalline silicon layer over said substrate; d) isotropically etching said polycrystalline silicon layer to remove said polycrystalline silicon from between said second and third protective structures and leaving a portion of said polycrystalline silicon between said first and second protective structures; e) oxidizing said substrate between said second and third protective structures and said polycrystalline silicon layer between said first and second protective structures.
Claim 3
Dependent Claim
26 words
The process of claim 1 further comprising the step of forming an oxide layer over said exposed portions of said substrate between steps b) and c).
Claim 4
Dependent Claim
26 words
The process of claim 2 wherein said oxide layer formed over said exposed portions of said substrate is from about 100 Å to about 1000 Å.
Claim 5
Dependent Claim
13 words
The process of claim 1 wherein said protective layer comprises nitride and oxide.
Claim 6
Dependent Claim
31 words
The process of claim 1 wherein said polycrystalline silicon layer formed during step c) is thicker between said first and second protective structures than between said second and third protective structures.
Claim 7
Dependent Claim
15 words
The process of claim 1 further comprising the step of doping said polycrystalline silicon layer.
Claim 8
Dependent Claim
29 words
The process of claim 1 wherein said field oxide between said first and second protective structures and between said second and third protective structures has a substantially uniform thickness.
Claim 9
Dependent Claim
181 words
A process for forming a semiconductor device, comprising the following steps: a) forming an oxide layer over a semiconductor substrate; b) forming a protective layer over said oxide layer; c) forming a patterned mask over said protective layer thereby forming exposed and covered portions of said protective layer; d) removing said exposed portions of said protective layer to form at least first, second, and third disconnected protective structures such that a first distance between said first and second protective structures is smaller than a second distance between said second and third protective structures; e) removing said oxide layer between said protective structures, and a portion of said substrate between said protective structures thereby exposing a portion of said substrate; f) forming a blanket polycrystalline silicon layer over said substrate; g) isotropically etching said polycrystalline silicon layer to remove said polycrystalline silicon from between said second and third protective structures and leaving a portion of said polycrystalline silicon between said first and second protective structures; h) oxidizing said polycrystalline silicon layer between said first and second protective structures to form field oxide.
Claim 10
Dependent Claim
181 words
A process for forming a semiconductor device, comprising the following steps: a) forming an oxide layer over a semiconductor substrate; b) forming a protective layer over said oxide layer; c) forming a patterned mask over said protective layer thereby forming exposed and covered portions of said protective layer; d) removing said exposed portions of said protective layer to form at least first, second, and third disconnected protective structures such that a first distance between said first and second protective structures is smaller than a second distance between said second and third protective structures; e) removing said oxide layer between said protective structures, and a portion of said substrate between said protective structures thereby exposing a portion of said substrate; f) forming a blanket polycrystalline silicon layer over said substrate; g) isotropically etching said polycrystalline silicon layer to remove said polycrystalline silicon from between said second and third protective structures and leaving a portion of said polycrystalline silicon between said first and second protective structures; h) oxidizing said polycrystalline silicon layer between said first and second protective structures to form field oxide.
Claim 11
Dependent Claim
26 words
The process of claim 8 further comprising the step of forming an oxide layer over said exposed portions of said substrate between steps e) and f).
Claim 12
Dependent Claim
26 words
The process of claim 9 wherein said oxide layer formed over said exposed portions of said substrate is from about 100 Å to about 1000 Å.
Claim 13
Dependent Claim
13 words
The process of claim 8 wherein said protective layer comprises nitride and oxide.
Claim 14
Dependent Claim
31 words
The process of claim 8 wherein said polycrystalline silicon layer formed during step f) is thicker between said first and second protective structures than between said second and third protective structures.
Claim 15
Dependent Claim
15 words
The process of claim 8 further comprising the step of doping said polycrystalline silicon layer.
Claim 16
Dependent Claim
52 words
The process of claim 8 further comprising the step of oxidizing said substrate between said second and third protective structures to form regions of field oxide, wherein said field oxide between said first and second protective structures is about as thick as said field oxide between said second and third protective structures.
Claim 17
Dependent Claim
219 words
A process for forming field oxide on a semiconductor substrate, comprising the following steps: a) forming an oxide layer over a semiconductor substrate; b) forming a protective layer over said oxide layer; c) forming a patterned mask over said protective layer thereby forming exposed and covered portions of said protective layer; d) removing said exposed portions of said protective layer to form at least first, second, and third disconnected protective structures such that a first distance between said first and second protective structures is smaller than a second distance between said second and third protective structures; e) removing said oxide layer between said protective structures, and a portion of said substrate between said protective structures thereby exposing a portion of said substrate; f) forming a blanket polycrystalline silicon layer over said substrate; g) isotropically etching said polycrystalline silicon layer to remove said polycrystalline silicon from between said second and third protective structures and leaving a portion of said polycrystalline silicon between said first and second protective structures; h) oxidizing said polycrystalline silicon layer between said first and second protective structures and between said second and third protective structures to form regions of field oxide, said field oxide between said first and second protective structures being about as thick as said field oxide between said second and third protective structures.
Claim 18
Dependent Claim
219 words
A process for forming field oxide on a semiconductor substrate, comprising the following steps: a) forming an oxide layer over a semiconductor substrate; b) forming a protective layer over said oxide layer; c) forming a patterned mask over said protective layer thereby forming exposed and covered portions of said protective layer; d) removing said exposed portions of said protective layer to form at least first, second, and third disconnected protective structures such that a first distance between said first and second protective structures is smaller than a second distance between said second and third protective structures; e) removing said oxide layer between said protective structures, and a portion of said substrate between said protective structures thereby exposing a portion of said substrate; f) forming a blanket polycrystalline silicon layer over said substrate; g) isotropically etching said polycrystalline silicon layer to remove said polycrystalline silicon from between said second and third protective structures and leaving a portion of said polycrystalline silicon between said first and second protective structures; h) oxidizing said polycrystalline silicon layer between said first and second protective structures and between said second and third protective structures to form regions of field oxide, said field oxide between said first and second protective structures being about as thick as said field oxide between said second and third protective structures.
Claim 19
Dependent Claim
26 words
The process of claim 15 further comprising the step of forming an oxide layer over said exposed portions of said substrate between steps e) and f).
Claim 20
Dependent Claim
26 words
The process of claim 16 wherein said oxide layer formed over said exposed portions of said substrate is from about 100 Å to about 1000 Å.
Claim 21
Dependent Claim
13 words
The process of claim 15 wherein said protective layer comprises nitride and oxide.
Claim 22
Dependent Claim
31 words
The process of claim 15 wherein said polycrystalline silicon layer formed during step f) is thicker between said first and second protective structures than between said second and third protective structures.
Claim 23
Dependent Claim
15 words
The process of claim 15 further comprising the step of doping said polycrystalline silicon layer.
Claim 24
Dependent Claim
33 words
The process of claim 14 wherein said polycrystalline silicon layer between said first and second protective structures and said substrate between said second and third protective structures are oxidized simultaneously during step h).
References Cited (Backward Citations)
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