Patent US5811345A successfully refreshed from Google Patents.
US5811345A
Expired / Lapsed
US
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Planarization of shallow- trench- isolation without chemical mechanical polishing
Assignee: Taiwan Semiconductor Manufacturing Co TSMC Ltd
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Filing: 1997-09-18
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Granted: 1998-09-22
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Expires: 2017-09-18
Abstract
Abstract A new method for planarization of shallow trench isolation is disclosed by the wet etching and plasma etching, due to the surface sensitivity of SACVD O 3 -TEOS that depends on substrate. The method described herein includes a pad oxide layer, a silicon nitride layer, and a doped polysilicon oxide layer formed on a silicon substrate. A shallow trench is formed by photolithography and dry etching process to etch the doped polysilicon oxide layer, the silicon nitride layer, the pad oxide layer, and the silicon substrate. A SACVD O 3 -TEOS layer is subsequently formed on the on the doped polysilicon oxide layer and filling into the trench, the deposition rate of the ozone-TEOS layer on the doped polysilicon oxide layer is slower than the deposition rate of the ozone-TEOS layer on the silicon wafer, the wet etching rate of the ozone-TEOS layer on the doped polysilicon oxide layer is faster than the etching rate of the ozone-TEOS layer on the silicon wafer. A wet etching is performed to planarize the ozone-TEOS layer.
Inventors
- 👤 Chen-Hua Yu
- 👤 Syun-Ming Jang Jang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:28
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/014; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; H10P95/00; H10P95/06; H10P95/062; H10W10/10; H10W10/17; Y; Y10; Y10S; Y10S438/00; Y10S438/914; Y10S438/916; Y10S438/924
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
165 words
A method for forming a shallow trench isolation on a silicon wafer, said method comprising the steps of: forming a pad oxide layer on said wafer; forming a silicon nitride layer on said pad layer; forming a doped polysilicon layer on said silicon nitride layer; performing a thermal annealing for converting said doped polysilicon layer into a doped polysilicon oxide layer; forming a trench by etching said doped polysilicon oxide layer, said silicon nitride layer, said pad oxide layer, and said silicon wafer; forming a ozone-TEOS layer for isolation on said doped polysilicon oxide layer and filling into said trench, the deposition rate of said ozone-TEOS layer on said doped polysilicon oxide layer is slower than the deposition rate of said ozone-TEOS layer on said silicon wafer, the wet etching rate of said ozone-TEOS layer on said doped polysilicon oxide layer is faster than the etching rate of said ozone-TEOS layer on said silicon wafer; and performing a wet etching to etch said ozone-TEOS layer.
Claim 2
Independent Claim
165 words
A method for forming a shallow trench isolation on a silicon wafer, said method comprising the steps of: forming a pad oxide layer on said wafer; forming a silicon nitride layer on said pad layer; forming a doped polysilicon layer on said silicon nitride layer; performing a thermal annealing for converting said doped polysilicon layer into a doped polysilicon oxide layer; forming a trench by etching said doped polysilicon oxide layer, said silicon nitride layer, said pad oxide layer, and said silicon wafer; forming a ozone-TEOS layer for isolation on said doped polysilicon oxide layer and filling into said trench, the deposition rate of said ozone-TEOS layer on said doped polysilicon oxide layer is slower than the deposition rate of said ozone-TEOS layer on said silicon wafer, the wet etching rate of said ozone-TEOS layer on said doped polysilicon oxide layer is faster than the etching rate of said ozone-TEOS layer on said silicon wafer; and performing a wet etching to etch said ozone-TEOS layer.
Claim 3
Dependent Claim
14 words
The method of claim 1, wherein said ozone-TEOS layer is formed by sub-atmospheric CVD.
Claim 4
Dependent Claim
24 words
The method of claim 1, wherein said the deposition rate of said ozone-TEOS layer on said silicon wafer is about 1500 to 2000 angstroms/minute.
Claim 5
Dependent Claim
25 words
The method of claim 1, wherein said the deposition rate of said ozone-TEOS layer on said doped-polysilicon oxide layer is about 100 to 150 angstroms/minute.
Claim 6
Dependent Claim
27 words
The method of claim 1, wherein said the wet etching rate of said ozone-TEOS layer on said doped polysilicon oxide layer is about 2000 to 3000 angstroms/minute.
Claim 7
Dependent Claim
25 words
The method of claim 1, wherein said the wet etching rate of said ozone-TEOS layer on said silicon wafer is about 280 to 320 angstroms/minute.
Claim 8
Dependent Claim
15 words
The method of claim 1, wherein the etchant of said wet etching is HF solution.
Claim 9
Dependent Claim
23 words
The method of claim 1, further comprising: performing a plasma etching to remove the remaining said ozone-TEOS layer after performing said wet etching.
Claim 10
Independent Claim
145 words
A method for forming a shallow trench isolation on a silicon wafer, said method comprising the steps of: forming a pad oxide layer on said wafer; forming a silicon nitride layer on said pad layer; forming a plasma-enhanced PSG layer on said silicon nitride layer; forming a trench by etching said plasma-enhanced PSG layer, said silicon nitride layer, said pad oxide layer, and said silicon wafer; forming a ozone-TEOS layer for isolation on said plasma-enhanced PSG layer and filling into said trench, the deposition rate of said ozone-TEOS layer on said plasma-enhanced PSG layer is slower than the deposition rate of said ozone-TEOS layer on said silicon wafer, the etching rate of said ozone-TEOS layer on said plasma-enhanced PSG layer is faster than the etching rate of said ozone-TEOS layer on said silicon wafer; and performing a wet etching process to etch said ozone-TEOS layer.
Claim 11
Independent Claim
145 words
A method for forming a shallow trench isolation on a silicon wafer, said method comprising the steps of: forming a pad oxide layer on said wafer; forming a silicon nitride layer on said pad layer; forming a plasma-enhanced PSG layer on said silicon nitride layer; forming a trench by etching said plasma-enhanced PSG layer, said silicon nitride layer, said pad oxide layer, and said silicon wafer; forming a ozone-TEOS layer for isolation on said plasma-enhanced PSG layer and filling into said trench, the deposition rate of said ozone-TEOS layer on said plasma-enhanced PSG layer is slower than the deposition rate of said ozone-TEOS layer on said silicon wafer, the etching rate of said ozone-TEOS layer on said plasma-enhanced PSG layer is faster than the etching rate of said ozone-TEOS layer on said silicon wafer; and performing a wet etching process to etch said ozone-TEOS layer.
Claim 12
Dependent Claim
14 words
The method of claim 9, wherein said ozone-TEOS layer is formed by sub-atmospheric CVD.
Claim 13
Dependent Claim
24 words
The method of claim 9, wherein said the deposition rate of said ozone-TEOS layer on said silicon wafer is about 1500 to 2000 angstroms/minute.
Claim 14
Dependent Claim
25 words
The method of claim 9, wherein said the deposition rate of said ozone-TEOS layer on said plasma-enhanced PSG layer is about 90 to 130 angstroms/minute.
Claim 15
Dependent Claim
25 words
The method of claim 9, wherein said the wet etching rate of said ozone-TEOS layer on said silicon wafer is about 280 to 320 angstroms/minute.
Claim 16
Dependent Claim
26 words
The method of claim 9, wherein said the wet etching rate of said ozone-TEOS layer on said plasma-enhanced PSG layer is about 2000 to 2500 angstroms/minute.
Claim 17
Dependent Claim
15 words
The method of claim 9, wherein the etchant of said wet etching is HF solution.
Claim 18
Dependent Claim
28 words
The method of claim 9, wherein said wet etching process further comprising: performing a plasma etching to remove the remaining said ozone-TEOS layer after performing said wet etching.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2001-09-21 | 2002-03-23 | 2002-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-09-21 | 2006-03-23 | 2006-09-22 | $3760.00 | Window Closed / Lapsed |
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