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US5904540A
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Method for manufacturing shallow trench isolation
Assignee: United Microelectronics Corp
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Filing: 1997-12-19
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Granted: 1999-05-18
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Expires: 2017-12-19
Abstract
Abstract A method for forming shallow trench isolation comprising the steps of providing a substrate having a mask layer formed thereon. Next, the mask layer is patterned to form a first trench in the substrate. Then, dielectric spacers are formed on the sidewalls of the first trench. After that, a second trench is formed in the substrate by an etching operation following the profile of the dielectric spacers. Next, a second dielectric layer is formed filling the second trench, wherein the second dielectric layer and the dielectric spacers are formed from different materials. Thereafter, the dielectric spacers are removed to form recess cavities, and then a filler material is deposited into the recess cavities. Subsequently, a gate oxide layer is formed over the filler material and the substrate. Finally, a polysilicon gate layer is formed over the gate oxide layer.
Inventors
- 👤 Yi-Chung Sheng
- 👤 Jih-Wen Chou
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:18
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/014; H10W10/0145; H10W10/10; H10W10/17
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
125 words
A method for manufacturing shallow trench isolation comprising the steps of: providing a substrate; forming a mask layer over the substrate; patterning the mask layer; forming a first trench in the substrate using the patterned mask; forming dielectric spacers in the interior of the first trench; etching into the substrate following the profile of the dielectric spacers to form a second trench; depositing a second dielectric layer that fills the second trench, wherein the second dielectric layer and the dielectric spacers are made from different materials; removing the dielectric spacers to form recess cavities; depositing a filler material into the recess cavities; forming a gate oxide layer over the substrate and over the filler material; and depositing a polysilicon gate over the gate oxide layer.
Claim 2
Independent Claim
125 words
A method for manufacturing shallow trench isolation comprising the steps of: providing a substrate; forming a mask layer over the substrate; patterning the mask layer; forming a first trench in the substrate using the patterned mask; forming dielectric spacers in the interior of the first trench; etching into the substrate following the profile of the dielectric spacers to form a second trench; depositing a second dielectric layer that fills the second trench, wherein the second dielectric layer and the dielectric spacers are made from different materials; removing the dielectric spacers to form recess cavities; depositing a filler material into the recess cavities; forming a gate oxide layer over the substrate and over the filler material; and depositing a polysilicon gate over the gate oxide layer.
Claim 3
Dependent Claim
24 words
The method of claim 1, wherein the step of forming the mask layer includes depositing a pad oxide layer and a silicon nitride layer.
Claim 4
Dependent Claim
46 words
The method of claim 1, wherein the step of forming the mask layer includes the substeps of: forming a pad oxide layer over the substrate; forming a silicon nitride layer over the pad oxide layer; and etching the pad oxide layer and the silicon nitride layer.
Claim 5
Dependent Claim
19 words
The method of claim 3, wherein the step of forming the pad oxide layer includes a thermal oxidation method.
Claim 6
Dependent Claim
59 words
The method of claim 1, wherein the step of forming dielectric spacers in the first trench includes the substeps of: forming a liner oxide layer on the expose substrate surface inside the trench interior; forming a dielectric layer over the liner oxide layer and over the mask layer; and etching back the dielectric layer to form the dielectric spacers.
Claim 7
Dependent Claim
18 words
The method of claim 5, wherein the step of forming the liner oxide layer includes depositing silicon dioxide.
Claim 8
Dependent Claim
19 words
The method of claim 5, wherein the step of forming the liner oxide layer includes a thermal oxidation method.
Claim 9
Dependent Claim
17 words
The method of claim 5, wherein the step of forming the dielectric layer includes depositing silicon nitride.
Claim 10
Dependent Claim
16 words
The method of claim 5, wherein the step of etching back includes a dry etching method.
Claim 11
Dependent Claim
39 words
The method of claim 1, wherein after the step of forming the second trench but before filling the trench with the second dielectric material, further includes forming a liner oxide layer on the exposed substrate inside the second trench.
Claim 12
Dependent Claim
18 words
The method of claim 10, wherein the step of forming the liner oxide layer includes depositing silicon dioxide.
Claim 13
Dependent Claim
19 words
The method of claim 5, wherein the step of forming the liner oxide layer includes a thermal oxidation method.
Claim 14
Dependent Claim
48 words
The method of claim 1, wherein the step of filling the second trench with second dielectric material includes the substeps of: depositing a dielectric material filling the second trench and over the mask layer; and polishing away the dielectric layer and the top portion of the mask layer.
Claim 15
Dependent Claim
15 words
The method of claim 13, wherein the step of polishing includes a chemical-mechanical polishing method.
Claim 16
Dependent Claim
18 words
The method of claim 1, wherein the step of removing the dielectric spacers include an isotropic etching operation.
Claim 17
Dependent Claim
18 words
The method of claim 15, wherein the step of performing an isotropic operation includes using hot phosphoric acid.
Claim 18
Dependent Claim
71 words
The method of claim 1, wherein the step of depositing a filler material into the recess cavities includes the substeps of: removing the pad oxide layer; forming a sacrificial oxide layer over the substrate; depositing a filler material into the recess cavities and extending into regions above the second trench; etching back the filler material using the sacrificial oxide layer as an etching stop layer; and removing the sacrificial oxide layer.
Claim 19
Dependent Claim
19 words
The method of claim 17, wherein the step of removing the pad oxide layer includes a wet etching method.
Claim 20
Dependent Claim
18 words
The method of claim 17, wherein the step of forming the sacrificial oxide layer includes depositing silicon dioxide.
Claim 21
Dependent Claim
19 words
The method of claim 17, wherein the step of forming the sacrificial oxide layer includes a thermal oxidation method.
Claim 22
Dependent Claim
13 words
The method of claim 17, wherein the filler material includes a conductive material.
Claim 23
Dependent Claim
11 words
The method of claim 21, wherein the conductive material includes polysilicon.
Claim 24
Dependent Claim
12 words
The method of claim 17, wherein the filler material includes insulating material.
Claim 25
Dependent Claim
12 words
The method of claim 23, wherein the insulating material includes silicon nitride.
Claim 26
Dependent Claim
19 words
The method of claim 17, wherein the step of removing the sacrificial oxide layer includes a wet etching method.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-05-17 | 2002-11-16 | 2003-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-17 | 2006-11-16 | 2007-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-05-17 | 2010-11-16 | 2011-05-18 | $7700.00 | Window Closed / Lapsed |