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US5895254A
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US
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Method of manufacturing shallow trench isolation structure
Assignee: United Microelectronics Corp
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Filing: 1997-12-18
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Granted: 1999-04-20
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Expires: 2017-12-18
Abstract
Abstract A method for forming a shallow trench isolation structure comprising the steps of sequentially forming a pad oxide layer and a mask layer over a substrate, then patterning the mask layer and the pad oxide layer. Next, an opening is formed in the mask layer, wherein the sidewall of the opening in the mask layer forms a sharp angle with the substrate layer below. Thereafter, the substrate is etched from the opening down to form a trench. In a subsequent step, insulating material is deposited into the trench forming an insulating layer rising to a level higher than the mask layer, and accompanying by the formation of a protuberance at the side of the insulating layer. Subsequently, the mask layer is removed, and then portions of the pad oxide layer is removed to form a spacer on the upper side of the insulating layer. Finally, the pad oxide layer above the substrate is removed to complete the formation of the shallow trench isolation structure. Due to the presence of a spacer, resistance against subsequent etching is increased at the junction between the trench insulating layer and the substrate layer. Thus, kink effect caused by the over-etching of the insulating layer is prevented.
Inventors
- 👤 Kuo-Tai Huang
- 👤 Tony Lin
- 👤 Water Lur
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:47
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/014; H10W10/10; H10W10/17; Y; Y10; Y10S; Y10S148/00; Y10S148/05
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
145 words
A method for manufacturing shallow trench isolation structure comprising the steps of: providing a substrate; forming a pad oxide layer and a mask layer above the substrate; patterning the mask layer and the pad oxide layer and etching to form an opening in the mask layer, wherein the sidewall of the mask layer forms an angle with the pad oxide layer; etching the pad oxide layer and the substrate through the opening to form a trench; depositing an insulating material into the trench to form an insulating layer, wherein the top surface of the insulating layer is at a higher level than the mask layer and has a protuberance attached to a side; removing the masking layer; removing portions of the pad oxide layer to form a spacer next to the sidewall of the insulating layer; and removing the pad oxide layer above the substrate.
Claim 2
Independent Claim
145 words
A method for manufacturing shallow trench isolation structure comprising the steps of: providing a substrate; forming a pad oxide layer and a mask layer above the substrate; patterning the mask layer and the pad oxide layer and etching to form an opening in the mask layer, wherein the sidewall of the mask layer forms an angle with the pad oxide layer; etching the pad oxide layer and the substrate through the opening to form a trench; depositing an insulating material into the trench to form an insulating layer, wherein the top surface of the insulating layer is at a higher level than the mask layer and has a protuberance attached to a side; removing the masking layer; removing portions of the pad oxide layer to form a spacer next to the sidewall of the insulating layer; and removing the pad oxide layer above the substrate.
Claim 3
Dependent Claim
36 words
The method of claim 1, wherein after the step of forming the trench and before depositing the insulating material into the trench, further includes forming a liner oxide layer on the interior surface of the trench.
Claim 4
Dependent Claim
20 words
The method of claim 2, wherein the step of forming the liner oxide layer includes using a thermal oxidation method.
Claim 5
Dependent Claim
17 words
The method of claim 1, wherein the step of forming the mask layer includes depositing silicon nitride.
Claim 6
Dependent Claim
19 words
The method of claim 1, wherein the step of etching the mask layer includes using a dry etching method.
Claim 7
Dependent Claim
29 words
The method of claim 1, wherein the step of forming the opening includes etching a sharp angle between the sidewall of the mask layer and the pad oxide layer.
Claim 8
Dependent Claim
17 words
The method of claim 6, wherein the angle is preferably in the range between 65° to 90°.
Claim 9
Dependent Claim
31 words
The method of claim 1, wherein the step of depositing insulating material into the trench further includes forming an insulating layer over the mask layer and etching back the insulating layer.
Claim 10
Dependent Claim
20 words
The method of claim 8, wherein the step of etching back the insulating layer includes using a chemical-mechanical polishing operation.
Claim 11
Dependent Claim
21 words
The method of claim 9, wherein the step of chemical-mechanical polishing includes using the mask layer as a polishing stop layer.
Claim 12
Dependent Claim
17 words
The method of claim 8, wherein the step of depositing insulating material includes depositing an oxide material.
Claim 13
Dependent Claim
23 words
The method of claim 1, wherein the step of removing the mask layer includes using hot phosphoric acid in a wet etching process.
Claim 14
Dependent Claim
22 words
The method of claim 1, wherein the step of removing portions of the pad oxide layer includes using a dry etching method.
Claim 15
Dependent Claim
30 words
The method of claim 1, wherein the protuberance in the insulating layer serves as a resistive barrier against etching during the etch removal of portions of the pad oxide layer.
Claim 16
Dependent Claim
27 words
The method of claim 1, wherein the step of removing the pad oxide layer from the substrate includes using hydrofluoric acid solution in a wet etching process.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-04-19 | 2002-10-19 | 2003-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-04-19 | 2006-10-19 | 2007-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-04-19 | 2010-10-19 | 2011-04-20 | $7700.00 | Window Closed / Lapsed |