US5656535A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Storage node process for deep trench-based DRAM
Assignee: Siemens AG
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Filing: 1996-03-04
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Granted: 1997-08-12
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Expires: 2016-03-04
Abstract
Abstract A simplified method of fabricating a storage node for a deep trench-based DRAM on a semiconductor substrate. The method involves the etching a trench in a surface of the substrate and then forming a layer of dielectric material on a sidewall of the trench the top portion of which is subsequently removed from the sidewall. Next, a layer of oxide is grown on the exposed portion of the sidewall. A portion of this layer of oxide is then removed from the sidewall in order to orient the layer of oxide a predetermined distance from the surface of the substrate. Finally, the trench is filled with a semiconductive material.
Inventors
- 👤 Herbert Ho
- 👤 Radhika Srinivasan
- 👤 Scott D. Halle
- 👤 Erwin Hammerl
- 👤 David M. Dobuzinsky
- 👤 Jack A. Mandelman
- 👤 Mark Anthony Jaso
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:01
CPC Classifications
H; H10; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10B12/038; H10B12/0387; H10B12/30; H10B12/37; H10B12/373; H10D; H10D1/00; H10D1/01; H10D1/045; H10D1/047; H10D1/60; H10D1/68; H10D1/692; H10D1/711; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/014; H10W10/0145; H10W10/10; H10W10/17; Y; Y10; Y10S; Y10S438/00; Y10S438/973
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
110 words
A method of fabricating a storage node for a deep trench-based DRAM on a semiconductor substrate, comprising the steps of: etching a trench in a surface of said substrate; forming a layer of dielectric material on a sidewall of said trench; partially removing said layer of dielectric material in order to expose an underlying region of an upper portion of said sidewall; growing a layer of oxide on said upper portion of said sidewall; removing a portion of said layer of oxide from said sidewall in order to orient said layer of oxide a predetermined distance from said surface of said substrate; and filling said trench with a semiconductive material.
Claim 2
Independent Claim
110 words
A method of fabricating a storage node for a deep trench-based DRAM on a semiconductor substrate, comprising the steps of: etching a trench in a surface of said substrate; forming a layer of dielectric material on a sidewall of said trench; partially removing said layer of dielectric material in order to expose an underlying region of an upper portion of said sidewall; growing a layer of oxide on said upper portion of said sidewall; removing a portion of said layer of oxide from said sidewall in order to orient said layer of oxide a predetermined distance from said surface of said substrate; and filling said trench with a semiconductive material.
Claim 3
Dependent Claim
22 words
The method according to claim 1, wherein said step of forming a layer of dielectric material includes low pressure chemical vapor deposition.
Claim 4
Dependent Claim
15 words
The method according to claim 2, wherein said layer of dielectric material comprises silicon nitride.
Claim 5
Dependent Claim
55 words
The method according to claim 1, wherein said step of partially removing said layer of dielectric material includes the steps of: filling said trench with a resist material; and etching said resist a predetermined depth thereby partially removing said layer of dielectric material and exposing said underlying region of said upper portion of said sidewall.
Claim 6
Dependent Claim
37 words
The method according to claim 1, wherein said step of growing a layer of oxide includes the step of oxidizing both said layer of dielectric material remaining on said sidewall and said exposed region of said sidewall.
Claim 7
Dependent Claim
24 words
The method according to claim 5, wherein said layer of oxide includes a collar-shaped oxide layer formed on said exposed region of said sidewall.
Claim 8
Dependent Claim
17 words
The method according to claim 6, wherein said collar-shaped oxide layer is approximately 50 nm in thickness.
Claim 9
Dependent Claim
48 words
The method according to claim 1, wherein said step of removing a portion of said layer of oxide includes the steps of: filling said trench with a resist material; and etching said resist a predetermined depth thereby removing said portion of said layer of oxide from said sidewall.
Claim 10
Dependent Claim
30 words
The method according to claim 8 wherein said step of etching said resist etches said underlying region of said sidewall exposed by said partial removal said layer of dielectric material.
Claim 11
Dependent Claim
19 words
The method according to claim 1, further comprising the step of planarizing said substrate after said step of filling.
Claim 12
Dependent Claim
11 words
The method according to claim 1, wherein said substrate is silicon.
Claim 13
Dependent Claim
12 words
The method according to claim 1, wherein said semiconductive material is polysilicon.
Claim 14
Dependent Claim
13 words
The method according to claim 12, wherein said polysilicon is doped with arsenic.
Claim 15
Independent Claim
92 words
A method of fabricating a storage node for a deep trench-based DRAM on a silicon substrate, comprising the steps of: etching a trench in a surface of said substrate; depositing a node dielectric on a sidewall of said trench; growing an oxide collar on said sidewall; filling said trench with a resist material; etching said resist a predetermined depth thereby removing a portion of said oxide collar from said sidewall in order to space said oxide collar a predetermined distance from said surface of said substrate; and filling said trench with polysilicon.
Claim 16
Independent Claim
92 words
A method of fabricating a storage node for a deep trench-based DRAM on a silicon substrate, comprising the steps of: etching a trench in a surface of said substrate; depositing a node dielectric on a sidewall of said trench; growing an oxide collar on said sidewall; filling said trench with a resist material; etching said resist a predetermined depth thereby removing a portion of said oxide collar from said sidewall in order to space said oxide collar a predetermined distance from said surface of said substrate; and filling said trench with polysilicon.
Claim 17
Dependent Claim
71 words
The method according to claim 14, further including the step of: partially removing said node dielectric prior to said step of growing, in order to expose an underlying region of an upper portion of said sidewall where said oxide collar will be grown, and wherein said step of growing includes: oxidizing both said node dielectric remaining on said sidewall and said exposed region of said sidewall to form said oxide collar.
Claim 18
Dependent Claim
51 words
The method according to claim 15, wherein said step of partially removing said node dielectric includes the steps of: filling said trench with a resist material; and etching said resist a predetermined depth thereby partially removing said node dielectric and exposing said underlying region of said upper portion of said sidewall.
Claim 19
Dependent Claim
28 words
The method according to claim 16, wherein said step of etching said resist etches said underlying region of said sidewall exposed by said partial removal said node dielectric.
Claim 20
Dependent Claim
17 words
The method according to claim 17, wherein said step of etching said resist includes chemical downstream etching.
Claim 21
Dependent Claim
19 words
The method according to claim 14, further comprising the step of planarizing said substrate after said step of filling.
Claim 22
Dependent Claim
16 words
The method according to claim 14, wherein said deep trench-based DRAM comprises a 256 Mb DRAM.
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) | 2000-08-11 | 2001-02-10 | 2001-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-11 | 2005-02-10 | 2005-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-11 | 2009-02-10 | 2009-08-12 | $7700.00 | Window Closed / Lapsed |