US5380671A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making non-trenched buried contact for VLSI devices
Assignee: United Microelectronics Corp
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Filing: 1994-06-13
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Granted: 1995-01-10
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Expires: 2014-06-13
Abstract
Abstract The invention describes a non-trenched buried contact for local interconnections in VLSI devices and provides a method for forming the non-trenched buried contact. By using trenched isolation and a trench polysilicon gate structure the buried contact process can be implemented so that there are no unwanted trenches formed in the area of the buried contact. The invention permits excellent planarization of the device prior to pre-metal dielectric and metal deposition.
Inventors
- 👤 Water Lur
- 👤 D. Y. Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:25
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/025; H10D64/027; H10W; H10W20/00; H10W20/01
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
227 words
A method of forming a semiconductor device, comprising the steps of: providing a silicon substrate; etching isolation trenches in said silicon substrate: filling said isolation trenches with an isolation dielectric material: etching gate electrode trenches with side walls, end walls, and bottoms in said silicon substrate: etching conductor electrode trenches with side walls, end walls, and bottoms in said silicon substrate and said isolation dielectric material wherein said conductor electrode trenches have contact ends; forming a gate dielectric layer on said side walls, said end walls, and said bottoms of said gate trenches and on said side walls, said end walls, and said bottoms of said electrode trenches at said contact ends; filling a said gate electrode trenches and said conductor electrode trenches with conductive electrode material: forming a thin oxide layer on the resulting structure; forming source and drain regions in the substrate using ion implant techniques; etching said thin oxide layer covering said contact ends of said conductor electrode trenches; forming a contact cavity by etching said gate dielectric layer from the top of said side walls and the top of said end walls at said contact ends of said conductor electrode trenches; filling said contact cavity with conductive contact material whereby the conductive electrode material is electrically connected to the source or drain; and forming a pre-metal dielectric layer over the semiconductor substrate surface.
Claim 2
Independent Claim
227 words
A method of forming a semiconductor device, comprising the steps of: providing a silicon substrate; etching isolation trenches in said silicon substrate: filling said isolation trenches with an isolation dielectric material: etching gate electrode trenches with side walls, end walls, and bottoms in said silicon substrate: etching conductor electrode trenches with side walls, end walls, and bottoms in said silicon substrate and said isolation dielectric material wherein said conductor electrode trenches have contact ends; forming a gate dielectric layer on said side walls, said end walls, and said bottoms of said gate trenches and on said side walls, said end walls, and said bottoms of said electrode trenches at said contact ends; filling a said gate electrode trenches and said conductor electrode trenches with conductive electrode material: forming a thin oxide layer on the resulting structure; forming source and drain regions in the substrate using ion implant techniques; etching said thin oxide layer covering said contact ends of said conductor electrode trenches; forming a contact cavity by etching said gate dielectric layer from the top of said side walls and the top of said end walls at said contact ends of said conductor electrode trenches; filling said contact cavity with conductive contact material whereby the conductive electrode material is electrically connected to the source or drain; and forming a pre-metal dielectric layer over the semiconductor substrate surface.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein said isolation trenches are etched to a depth of between about 4000 and 10,000 Angstroms.
Claim 4
Dependent Claim
14 words
The method of claim 1 wherein said isolation dielectric material is SiO 2 .
Claim 5
Dependent Claim
13 words
The method of claim 1 wherein said isolation dielectric material is silicon nitride.
Claim 6
Dependent Claim
13 words
The method of claim 1 wherein said isolation dielectric material is borophosphosilicate glass.
Claim 7
Dependent Claim
23 words
The method of claim 1 wherein said gate electrode trenches and said conductor electrode trenches are between about 1500 and 6000 Angstroms deep.
Claim 8
Dependent Claim
12 words
The method of claim 1 wherein said conductive electrode material is polysilicon.
Claim 9
Dependent Claim
12 words
The method of claim 1 wherein said conductive contact material is polysilicon.
Claim 10
Dependent Claim
30 words
The method of claim 1 wherein said conductive contact material is a silicide selected from the group consisting of TiSi 2 , TaSi 2 , tungsten silicide and molybdenum silicide.
Claim 11
Dependent Claim
23 words
The method of claim 1 wherein said conductive contact material is a metal selected from the group consisting of Ti, W, and Al.
Claim 12
Dependent Claim
14 words
The method of claim 1 wherein said conductive contact material is TiN or Ti:W.
Claim 13
Dependent Claim
18 words
The method of claim 1 wherein said gate dielectric layer is between about 50 and 300 Angstroms thick.
Claim 14
Dependent Claim
22 words
The method of claim 1 wherein said gate dielectric layer is SiO 2 , silicon nitride or Ta 2 O 5 .
References Cited (Backward Citations)
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) | 1998-01-09 | 1998-07-11 | 1999-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-01-09 | 2002-07-11 | 2003-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-01-09 | 2006-07-11 | 2007-01-10 | $7700.00 | Window Closed / Lapsed |