Patent US5719080A successfully refreshed from Google Patents.
US5719080A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor trench capacitor cell having a buried strap
Assignee: International Business Machines Corp
•
Filing: 1995-08-31
•
Granted: 1998-02-17
•
Expires: 2015-08-31
Abstract
Abstract A semiconductor trench capacitor structure having a first level aligned isolation structure and buried strap that extends from within the trench into the doped semiconductor substrate. The semiconductor trench capacitor structure may be fabricated by forming a shallow trench within the trench capacitor and semiconductor substrate, depositing a layer of conductive material within the shallow trench, using a mask to define and recess the strap and depositing insulating material within the shallow trench.
Inventors
- 👤 Donald M. Kenney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:47
CPC Classifications
H; H10; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10B12/038
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
147 words
A process for producing a semiconductor device having a buried strap, comprising: forming a first trench in a semiconductor substrate, said first trench having an insulation region with a conductive material situated therein; forming a second trench in said first trench and extending into said semiconductor substrate; forming a layer of conductive material within said second trench wherein the conductive material lies below the surface of the semiconductor substrate; depositing a protective layer over a contiguous portion of the conductive material within said second trench, wherein said contiguous portion of the conductive material extends over said first trench and said semiconductor substrate and defines a buried strap; recessing the exposed portions of said second trench below the depth of said buried strap; removing said protective layer; forming an insulation region within said second trench; and forming an insulation layer over the conductive material within said first trench.
Claim 2
Dependent Claim
147 words
A process for producing a semiconductor device having a buried strap, comprising: forming a first trench in a semiconductor substrate, said first trench having an insulation region with a conductive material situated therein; forming a second trench in said first trench and extending into said semiconductor substrate; forming a layer of conductive material within said second trench wherein the conductive material lies below the surface of the semiconductor substrate; depositing a protective layer over a contiguous portion of the conductive material within said second trench, wherein said contiguous portion of the conductive material extends over said first trench and said semiconductor substrate and defines a buried strap; recessing the exposed portions of said second trench below the depth of said buried strap; removing said protective layer; forming an insulation region within said second trench; and forming an insulation layer over the conductive material within said first trench.
Claim 3
Dependent Claim
21 words
The process of claim 1 further comprising forming a dielectric layer over said semiconductor substrate prior to forming said first trench.
Claim 4
Dependent Claim
35 words
The process of claim 2, wherein said dielectric layer is formed by first forming a layer of silicon oxide over said semiconductor substrate and then forming a layer of silicon nitride over said silicon oxide.
Claim 5
Dependent Claim
30 words
The process of claim 1 wherein said insulation layer comprises silicon oxide and wherein said process further comprises the step of densifying said insulation layer after forming said insulation layer.
Claim 6
Dependent Claim
59 words
The process of claim 1, wherein said first trench is defined by an interior wall having an upper and lower portion and wherein forming said first trench having said insulation region comprises: forming a thin insulation layer on the lower portion of said interior wall; and forming a thick insulation layer on the upper portion of said interior wall.
Claim 7
Dependent Claim
19 words
The process of claim 1 wherein said conductive material deposited in said first trench comprises a p+ doped polysilicon.
Claim 8
Dependent Claim
17 words
The process of claim 6 wherein said conductive material deposited in said second trench comprises undoped polysilicon.
Claim 9
Dependent Claim
21 words
The process of claim 5 wherein prior to removing said protective layer the conductive material within said first trench is recessed.
Claim 10
Dependent Claim
47 words
The process of claim 2 wherein forming layer of conductive material within said second trench below the surface of said semiconductor substrate comprises: depositing a conductive material within said second trench; and recessing said conductive material within said second trench below the surface of said semiconductor substrate.
Claim 11
Dependent Claim
22 words
The process of claim 9 further comprising recessing the conductive material within said first trench below the surface of said semiconductor substrate.
Claim 12
Dependent Claim
46 words
The process of claim 10 wherein said recessing of the conductive material within said second trench and said recessing of the conductive material within said first trench are performed simultaneously by application of an etch that selectively etches said conductive material relative to said dielectric layer.
Claim 13
Dependent Claim
39 words
The process of claim 10 wherein forming said insulation region within said second trench and forming an insulation layer over said first trench comprises simultaneously depositing an insulating material within said recessed portions of said first and second trenches.
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) | 2001-02-16 | 2001-08-18 | 2002-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-02-16 | 2005-08-18 | 2006-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-02-16 | 2009-08-18 | 2010-02-17 | $7700.00 | Window Closed / Lapsed |