US6165869A
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US
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Method to avoid dishing in forming trenches for shallow trench isolation
Assignee: GlobalFoundries Singapore Pte Ltd
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Filing: 1998-06-11
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Granted: 2000-12-26
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Expires: 2018-06-11
Abstract
Abstract A method is described for filling trenches with dielectric for shallow trench isolation which completely fills the trench and avoids problems due to dishing at the top of the trench. A trench is formed in a substrate having a second dielectric material formed thereon. The trench is lined with a third dielectric material. Sub atmospheric chemical vapor deposition, SACVD, of tetra-ethyl-ortho-silicate and ozone is used to grow a fourth dielectric on the surface of the second dielectric material and in the trench lined with the third dielectric material. The growth rate of fourth dielectric on the third dielectric is greater than the growth rate of the fourth dielectric on the second dielectric using SACVD of tetra-ethyl-ortho-silicate and ozone. The difference in growth rate assures that the trench is completely filled with fourth dielectric even for relatively thin layers of fourth dielectric grown on the second dielectric. This provides good planarity for a planarized substrate and avoids the problem of dishing at the top of the trench.
Inventors
- 👤 Gang Qian
- 👤 Chock Hing Gan
- 👤 Lap Hung Chan
- 👤 Poh Suan Tan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:44
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/014; H10W10/10; H10W10/17
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
396 words
A method of forming isolation trenches, comprising the steps of: providing a substrate; forming a layer of first dielectric having, a top surface, on said substrate; forming a layer of second dielectric, having a top surface, on said top surface of said layer of first dielectric; patterning said layer of first dielectric and said layer of second dielectric thereby forming a trench pattern, having sidewalls, in said layer of first dielectric and said layer of second dielectric; etching a trench, having sidewalls and a bottom, in said substrate wherein said trench is directly below said trench pattern in said layer of first dielectric and said layer of second dielectric; forming an oxide liner on said sidewalls and said bottom of said trench; forming a layer of third dielectric on said top surface of said layer of second dielectric, said sidewalls of said trench pattern, and said oxide liner formed on said sidewalls and bottom of said trench, wherein said layer of third dielectric is formed after said patterning said layer of first dielectric and said layer of second dielectric has been completed; removing that part of said layer of third dielectric above the plane of said top surface of said layer of second dielectric thereby leaving that part of said layer of third dielectric on said sidewalls of said trench pattern and on said oxide liner formed on said sidewalls and said bottom of said trench; forming a layer of fourth dielectric on said top surface of said layer of second dielectric and on that part of said layer of third dielectric on said sidewalls of said trench pattern and on said oxide liner formed on said sidewalls and said bottom of said trench, after removing that part of said layer of third dielectric above the plane of said top surface of said layer of said second dielectric, using a method wherein the rate of formation of said fourth dielectric on said third dielectric is greater than the rate of formation of said fourth dielectric on said second dielectric, thereby filling said trench with said fourth dielectric; and removing that part of said layer of fourth dielectric, that part of said layer of third dielectric, and that part of said layer of second dielectric above the plane of said of said top surface of said layer of first dielectric leaving said fourth dielectric in said trench.
Claim 2
Independent Claim
396 words
A method of forming isolation trenches, comprising the steps of: providing a substrate; forming a layer of first dielectric having, a top surface, on said substrate; forming a layer of second dielectric, having a top surface, on said top surface of said layer of first dielectric; patterning said layer of first dielectric and said layer of second dielectric thereby forming a trench pattern, having sidewalls, in said layer of first dielectric and said layer of second dielectric; etching a trench, having sidewalls and a bottom, in said substrate wherein said trench is directly below said trench pattern in said layer of first dielectric and said layer of second dielectric; forming an oxide liner on said sidewalls and said bottom of said trench; forming a layer of third dielectric on said top surface of said layer of second dielectric, said sidewalls of said trench pattern, and said oxide liner formed on said sidewalls and bottom of said trench, wherein said layer of third dielectric is formed after said patterning said layer of first dielectric and said layer of second dielectric has been completed; removing that part of said layer of third dielectric above the plane of said top surface of said layer of second dielectric thereby leaving that part of said layer of third dielectric on said sidewalls of said trench pattern and on said oxide liner formed on said sidewalls and said bottom of said trench; forming a layer of fourth dielectric on said top surface of said layer of second dielectric and on that part of said layer of third dielectric on said sidewalls of said trench pattern and on said oxide liner formed on said sidewalls and said bottom of said trench, after removing that part of said layer of third dielectric above the plane of said top surface of said layer of said second dielectric, using a method wherein the rate of formation of said fourth dielectric on said third dielectric is greater than the rate of formation of said fourth dielectric on said second dielectric, thereby filling said trench with said fourth dielectric; and removing that part of said layer of fourth dielectric, that part of said layer of third dielectric, and that part of said layer of second dielectric above the plane of said of said top surface of said layer of first dielectric leaving said fourth dielectric in said trench.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein said layer of first dielectric is a layer of silicon nitride.
Claim 4
Dependent Claim
17 words
The method of claim 1 wherein said layer of second dielectric is a layer of silicon oxide.
Claim 5
Dependent Claim
17 words
The method of claim 1 wherein said layer of third dielectric is a layer of silicon nitride.
Claim 6
Dependent Claim
23 words
The method of claim 1 wherein said fourth dielectric is silicon oxide formed using sub atmospheric chemical vapor deposition from tetra-ethyl-ortho-silicate and ozone.
Claim 7
Dependent Claim
40 words
The method of claim 1 wherein said second dielectric is silicon oxide, said third dielectric is silicon nitride, said fourth dielectric is silicon oxide, and said fourth dielectric is formed using sub atmospheric chemical vapor deposition from tetra-ethyl-ortho-silicate and ozone.
Claim 8
Dependent Claim
23 words
The method of claim 1 wherein said substrate is silicon and said oxide liner is silicon oxide formed by thermal oxidation of silicon.
Claim 9
Dependent Claim
38 words
The method of claim 1 wherein said removing that part of said layer of third dielectric above the plane of said top surface of said layer of said second dielectric is accomplished using a first chemical mechanical polishing.
Claim 10
Dependent Claim
54 words
The method of claim 1 wherein said removing that part of said layer of fourth dielectric, that part of said layer of third dielectric, and that part of said layer of second dielectric above the plane of said of said top surface of said layer of first dielectric uses a second chemical mechanical polishing.
Claim 11
Dependent Claim
14 words
The method of claim 1 wherein said substrate is a silicon integrated circuit wafer.
Claim 12
Dependent Claim
23 words
The method of claim 1 wherein said etching a trench having sidewalls and a bottom in said substrate uses vertical dry anisotropic etching.
Claim 13
Independent Claim
419 words
A method of forming isolation trenches, comprising the steps of: providing a substrate; forming a layer of pad oxide on said substrate; forming a layer of first dielectric, having a top surface, on said layer of pad oxide; forming a layer of second dielectric, having a top surface, on said top surface of said layer of first dielectric; forming a layer of resist on said top surface of said layer of second dielectric; patterning said layer of resist, thereby forming a resist mask; patterning said layer of first dielectric, said layer of second dielectric, and said layer of pad oxide using said resist mask thereby forming a trench pattern having sidewalls in said layer of first dielectric, said layer of second dielectric, and said layer of pad oxide; etching a trench having sidewalls and a bottom in said substrate using said resist mask wherein said trench is directly below said trench pattern; removing said resist mask; forming an oxide liner on said sidewalls and said bottom of said trench; forming a layer of third dielectric on said top surface of said patterned layer of second dielectric, said sidewalls of said trench pattern, and said oxide liner formed on said sidewalls and bottom of said trench; removing that part of said layer of third dielectric above the plane of said top surface of said layer of second dielectric thereby leaving that part of said layer of third dielectric on said sidewalls of said trench pattern and on said oxide liner formed on said sidewalls and said bottom of said trench; forming a layer of fourth dielectric on said top surface of said layer of second dielectric, on that part of said layer of third dielectric formed on said sidewalls of said trench pattern, and on said oxide liner formed on said sidewalls and said bottom of said trench, after removing that part of said layer of third dielectric above the plane of said top surface of said layer of said second dielectric, using a method wherein the rate of formation of said fourth dielectric on said third dielectric is greater than the rate of formation of said fourth dielectric on said second dielectric thereby filling said trench with said fourth dielectric; and removing that part of said layer of fourth dielectric, that part of said layer of third dielectric, and that part of said layer of second dielectric above the plane of said of said top surface of said layer of first dielectric, leaving said fourth dielectric in said trench.
Claim 14
Independent Claim
419 words
A method of forming isolation trenches, comprising the steps of: providing a substrate; forming a layer of pad oxide on said substrate; forming a layer of first dielectric, having a top surface, on said layer of pad oxide; forming a layer of second dielectric, having a top surface, on said top surface of said layer of first dielectric; forming a layer of resist on said top surface of said layer of second dielectric; patterning said layer of resist, thereby forming a resist mask; patterning said layer of first dielectric, said layer of second dielectric, and said layer of pad oxide using said resist mask thereby forming a trench pattern having sidewalls in said layer of first dielectric, said layer of second dielectric, and said layer of pad oxide; etching a trench having sidewalls and a bottom in said substrate using said resist mask wherein said trench is directly below said trench pattern; removing said resist mask; forming an oxide liner on said sidewalls and said bottom of said trench; forming a layer of third dielectric on said top surface of said patterned layer of second dielectric, said sidewalls of said trench pattern, and said oxide liner formed on said sidewalls and bottom of said trench; removing that part of said layer of third dielectric above the plane of said top surface of said layer of second dielectric thereby leaving that part of said layer of third dielectric on said sidewalls of said trench pattern and on said oxide liner formed on said sidewalls and said bottom of said trench; forming a layer of fourth dielectric on said top surface of said layer of second dielectric, on that part of said layer of third dielectric formed on said sidewalls of said trench pattern, and on said oxide liner formed on said sidewalls and said bottom of said trench, after removing that part of said layer of third dielectric above the plane of said top surface of said layer of said second dielectric, using a method wherein the rate of formation of said fourth dielectric on said third dielectric is greater than the rate of formation of said fourth dielectric on said second dielectric thereby filling said trench with said fourth dielectric; and removing that part of said layer of fourth dielectric, that part of said layer of third dielectric, and that part of said layer of second dielectric above the plane of said of said top surface of said layer of first dielectric, leaving said fourth dielectric in said trench.
Claim 15
Dependent Claim
17 words
The method of claim 12 wherein said layer of first dielectric is a layer of silicon nitride.
Claim 16
Dependent Claim
17 words
The method of claim 12 wherein said layer of second dielectric is a layer of silicon oxide.
Claim 17
Dependent Claim
17 words
The method of claim 12 wherein said layer of third dielectric is a layer of silicon nitride.
Claim 18
Dependent Claim
23 words
The method of claim 12 wherein said fourth dielectric is silicon oxide formed using sub atmospheric chemical vapor deposition from tetra-ethyl-ortho-silicate and ozone.
Claim 19
Dependent Claim
40 words
The method of claim 12 wherein said second dielectric is silicon oxide, said third dielectric is silicon nitride, said fourth dielectric is silicon oxide, and said fourth dielectric is formed using sub atmospheric chemical vapor deposition from tetra-ethyl-ortho-silicate and ozone.
Claim 20
Dependent Claim
23 words
The method of claim 12 wherein said substrate is silicon and said oxide liner is silicon oxide formed by thermal oxidation of silicon.
Claim 21
Dependent Claim
33 words
The method of claim 12 wherein said removing that part of said third dielectric above the plane of said top surface of said layer of second dielectric uses a first chemical mechanical polishing.
Claim 22
Dependent Claim
54 words
The method of claim 12 wherein said removing that part of said layer of fourth dielectric, that part of said layer of third dielectric, and that part of said layer of second dielectric above the plane of said of said top surface of said layer of first dielectric uses a second chemical mechanical polishing.
Claim 23
Dependent Claim
14 words
The method of claim 12 wherein said substrate is a silicon integrated circuit wafer.
Claim 24
Dependent Claim
23 words
The method of claim 12 wherein said etching said trench having sidewalls and a bottom in said substrate uses vertical dry anisotropic etching.
References Cited (Backward Citations)
US3911474A
Cited
US4576834A
Cited
US5229310A
Cited
US5399389A
Cited
US5492858A
Cited
US5447884A
Cited
US5994756A
Cited
US5674783A
Cited
US5945724A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-12-26 | 2004-06-26 | 2004-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-12-26 | 2008-06-26 | 2008-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-12-26 | 2012-06-26 | 2012-12-26 | $7700.00 | Window Closed / Lapsed |