US6057210A
Expired / Lapsed
US
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Method of making a shallow trench isolation for ULSI formation via in-direct CMP process
Assignee: Vanguard International Semiconductor Corp
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Filing: 1998-04-21
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Granted: 2000-05-02
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Expires: 2018-04-21
Abstract
Abstract A silicon dioxide layer and a silicon nitride layer are formed on the wafer. Subsequently, a plurality of shallow trenches are generated in the wafer. A HDP-CVD oxide having protruding portions is refilled into the trenches and formed on the silicon nitride layer for isolation. A wet etch is performed to etch the HDP-CVD oxide layer such that the corners of the silicon nitride layer formed on the active area will be exposed. A cap silicon nitride layer is then conformally formed on the surface of the oxide layer. Then, a chemical mechanical polishing (CMP) process is used to remove the top of the cap silicon nitride layer, thereby exposing the residual protruding portions of the oxide layer. The residual protruding portions of the oxide layer are next removed. Then, the silicon nitride layer and the cap silicon nitride layer are both removed by conventional methods. Finally, the pad oxide is removed.
Inventors
- 👤 Fu-Liang Yang
- 👤 Wei-Ray Lin
- 👤 Ming-Hong Kuo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 00:18
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/014; H10W10/0143; H10W10/10; H10W10/17; Y; Y10; Y10S; Y10S148/00; Y10S148/05
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
140 words
A method of forming trench isolations on a silicon wafer, said method comprising: forming a pad layer on said silicon wafer; forming a first silicon nitride layer on said pad layer; forming trenches by etching said first silicon nitride layer, said pad layer and said silicon wafer; forming an HDP-CVD oxide on said first silicon nitride layer and into said trenches, said oxide having protruding portions formed thereon and aligned to an active area of said wafer; etching said HDP-CVD oxide to expose corners of said silicon nitride layer, thereby separating said HDP-CVD oxide into protruding portions on said active area and trench portions within said trenches; forming a second silicon nitride layer on said oxide and said protruding portions; exposing said residual protruding portions; removing said residual protruding portions; and removing said first and said second silicon nitride layers.
Claim 2
Independent Claim
140 words
A method of forming trench isolations on a silicon wafer, said method comprising: forming a pad layer on said silicon wafer; forming a first silicon nitride layer on said pad layer; forming trenches by etching said first silicon nitride layer, said pad layer and said silicon wafer; forming an HDP-CVD oxide on said first silicon nitride layer and into said trenches, said oxide having protruding portions formed thereon and aligned to an active area of said wafer; etching said HDP-CVD oxide to expose corners of said silicon nitride layer, thereby separating said HDP-CVD oxide into protruding portions on said active area and trench portions within said trenches; forming a second silicon nitride layer on said oxide and said protruding portions; exposing said residual protruding portions; removing said residual protruding portions; and removing said first and said second silicon nitride layers.
Claim 3
Dependent Claim
24 words
The method of claim 1, wherein said residual protruding portions are exposed by using chemical mechanical polishing to remove said second silicon nitride layer.
Claim 4
Dependent Claim
19 words
The method of claim 1, wherein said HDP-CVD oxide is formed at a temperature of about 300-900 degrees centigrade.
Claim 5
Dependent Claim
21 words
The method of claim 1, wherein said corners of said first silicon nitride layer are exposed by using a HF solution.
Claim 6
Dependent Claim
20 words
The method of claim 1, wherein said corners of said first silicon nitride layer are exposed by using a BOE.
Claim 7
Dependent Claim
16 words
The method of claim 1, wherein said residual protruding portions are removed by using HF solution.
Claim 8
Dependent Claim
16 words
The method of claim 1, wherein said residual protruding portions are removed by using BOE solution.
Claim 9
Dependent Claim
22 words
The method of claim 1, wherein said first and said second silicon nitride layers are removed by a hot phosphorus acid solution.
Claim 10
Dependent Claim
15 words
The method of claim 1, wherein said pad oxide layer is removed by HF solution.
Claim 11
Dependent Claim
14 words
The method of claim 1, wherein said pad layer is removed by BOE solution.
Claim 12
Independent Claim
129 words
A method of forming trench isolations on a silicon wafer, said method comprising: forming a pad layer on said silicon wafer; forming a first silicon nitride layer on said pad layer; forming trenches by etching said first silicon nitride layer, said pad layer and said silicon wafer; forming a HDP-CVD oxide on said first silicon nitride layer and into said trenches, said HDP-CVD oxide having protruding portions formed thereon and aligned to an active area of said wafer, said HDP-CVD oxide in said trenches being separated from said protruding portions by exposed corners of said first silicon nitride layer; forming a second silicon nitride layer on said oxide and said protruding portions; exposing said protruding portions; removing said protruding portions; removing said first and said second silicon nitride layers.
Claim 13
Independent Claim
129 words
A method of forming trench isolations on a silicon wafer, said method comprising: forming a pad layer on said silicon wafer; forming a first silicon nitride layer on said pad layer; forming trenches by etching said first silicon nitride layer, said pad layer and said silicon wafer; forming a HDP-CVD oxide on said first silicon nitride layer and into said trenches, said HDP-CVD oxide having protruding portions formed thereon and aligned to an active area of said wafer, said HDP-CVD oxide in said trenches being separated from said protruding portions by exposed corners of said first silicon nitride layer; forming a second silicon nitride layer on said oxide and said protruding portions; exposing said protruding portions; removing said protruding portions; removing said first and said second silicon nitride layers.
Claim 14
Dependent Claim
24 words
The method of claim 11, wherein said residual protruding portions are exposed by using chemical mechanical polishing to remove said second silicon nitride layer.
Claim 15
Dependent Claim
18 words
The method of claim 11, wherein said oxide is formed at a temperature of about 300-900 degrees centigrade.
Claim 16
Dependent Claim
20 words
The method of claim 11, wherein said corners of said first silicon nitride layer are exposed by using HF solution.
Claim 17
Dependent Claim
22 words
The method of claim 11, wherein said corners of said first silicon nitride layer are exposed by using BOE (buffer oxide solution).
Claim 18
Dependent Claim
16 words
The method of claim 11, wherein said residual protruding portions are removed by using HF solution.
Claim 19
Dependent Claim
16 words
The method of claim 11, wherein said residual protruding portions are removed by using BOE solution.
Claim 20
Dependent Claim
21 words
The method of claim 11, wherein said first and said second silicon nitride layer are removed by hot phosphorus acid solution.
Claim 21
Dependent Claim
15 words
The method of claim 11, wherein said pad oxide layer is removed by HF solution.
Claim 22
Dependent Claim
14 words
The method of claim 11, wherein said pad layer is removed by BOE solution.
References Cited (Backward Citations)
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