US4984039A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tapered trench structure and process
Assignee: Texas Instruments Inc
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Filing: 1990-06-11
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Granted: 1991-01-08
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Expires: 2010-06-11
Abstract
Abstract A plasma dry etch process for etching deep trenches in single crystal silicon material with controlled wall profile, for trench capacitors or trench isolation structures. HCl is used as an etchant under RIE conditions with a SiO 2 hard mask. The SiO 2 hard mask is forward sputtered during the course of the Si etch so as to slowly deposit SiO x (x<2) on the sidewalls of the silicon trench. Since the sidewall deposit shadows etching at the bottom of the trench near the sidewall, the effect of this gradual buildup is to produce a positively sloped trench sidewall without "grooving" the bottom of the trench, and without linewidth loss. This process avoids the prior art problems of mask undercut, which generates voids during subsequent refill processing, and grooving at the bottom of the trench, which is exceedingly deleterious to thin capacitor dielectric integrity.
Inventors
- 👤 Monte A. Douglas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:54
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/69; H10P50/691; H10P50/693; H10P50/694; H10P50/20; H10P50/24; H10P50/242; H10P50/244
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
54 words
An integrated circuit having a sidewall formed in a surface of a monocrystalline substrate comprising: (a) a first portion of said sidewall being positively sloped; (b) a second portion of said sidewall being substantially vertical and without bowing or undercut; and (c) a material in contact with at least a part of said sidewall.
Claim 2
Dependent Claim
54 words
An integrated circuit having a sidewall formed in a surface of a monocrystalline substrate comprising: (a) a first portion of said sidewall being positively sloped; (b) a second portion of said sidewall being substantially vertical and without bowing or undercut; and (c) a material in contact with at least a part of said sidewall.
Claim 3
Dependent Claim
19 words
An integrated circuit as in claim 1 wherein said first portion is between said surface and said second portion.
Claim 4
Dependent Claim
18 words
An integrated circuit as in claim 1 wherein said first portion opens onto said surface of said substrate.
Claim 5
Dependent Claim
26 words
An integrated circuit as in claim 1 wherein said first portion is at an angle substantially within the range of 85° to 87° to said surface.
Claim 6
Dependent Claim
26 words
An integrated circuit as in claim 1 wherein said second portion is at an angle substantially within the range of 89° to 90° to said surface.
Claim 7
Dependent Claim
13 words
An integrated circuit as in claim 1 wherein said substrate comprises monocrystalline silicon.
Claim 8
Dependent Claim
13 words
An integrated circuit as in claim 1 wherein said material is an oxide.
Claim 9
Dependent Claim
18 words
An integrated circuit as in claim 2 wherein said first portion opens onto said surface of said substrate.
Claim 10
Dependent Claim
13 words
An integrated circuit as in claim 8 wherein said material is an oxide.
Claim 11
Dependent Claim
26 words
An integrated circuit as in claim 9 wherein said second portion is at an angle substantially within the range of 89° to 90° to said surface.
Claim 12
Dependent Claim
26 words
An integrated circuit as in claim 10 wherein said first portion is at an angle substantially within the range of 85° to 87° to said surface.
Claim 13
Dependent Claim
13 words
An integrated circuit as in claim 11 wherein said substrate comprises monocrystalline silicon.
Claim 14
Dependent Claim
70 words
An integrated circuit formed on a substrate comprising: (a) a surface of said substrate; (b) a sidewall having a first portion extending from said surface into said substrate at a first angle, a second portion without bowing or undercut and extending from said first portion into said substrate at a second angle; and (c) at least one device formed at least partly along at least a part of said sidewall.
Claim 15
Dependent Claim
70 words
An integrated circuit formed on a substrate comprising: (a) a surface of said substrate; (b) a sidewall having a first portion extending from said surface into said substrate at a first angle, a second portion without bowing or undercut and extending from said first portion into said substrate at a second angle; and (c) at least one device formed at least partly along at least a part of said sidewall.
Claim 16
Dependent Claim
14 words
The integrated circuit as in claim 13 wherein said one device is a capacitor.
Claim 17
Dependent Claim
17 words
The integrated circuit as in claim 13 wherein said second angle is greater than said first angle.
Claim 18
Dependent Claim
20 words
The integrated circuit as in claim 15 wherein said second portion is positively sloped and substantially perpendicular to said surface.
Claim 19
Dependent Claim
19 words
The integrated circuit as in claim 16 wherein said first angle is in the range of 85° to 87°.
Claim 20
Dependent Claim
19 words
The integrated circuit as in claim 16 wherein said second angle is in the range of 89° to 90°.
Claim 21
Dependent Claim
20 words
The integrated circuit as in claim 13 wherein said second portion is positively sloped and substantially perpendicular to said surface.
Claim 22
Dependent Claim
19 words
The integrated circuit as in claim 13 wherein said first angle is in the range of 85° to 87°.
Claim 23
Dependent Claim
19 words
The integrated circuit as in claim 13 wherein said second angle is in the range of 89° to 90°.
Claim 24
Dependent Claim
31 words
The integrated circuit as in claim 13 wherein said first angle is in the range of 85° to 87° and said second angle is in the range of 89° to 90°.
Claim 25
Dependent Claim
13 words
The integrated circuit as in claim 13 wherein said substrate comprises monocrystalline silicon.
Claim 26
Dependent Claim
14 words
The integrated circuit as in claim 23 wherein said one device is a capacitor.
Claim 27
Dependent Claim
27 words
The integrated circuit as in claim 14 wherein said capacitor includes one plate adjacent said part of said sidewall and another plate extending along said one plate.
Claim 28
Dependent Claim
16 words
The integrated circuit as in claim 25 wherein said another plate includes a layer of polysilicon.
Claim 29
Dependent Claim
23 words
The integrated circuit as in claim 26 wherein said another plate is spaced from said part of said sidewall by an insulating layer.
Claim 30
Dependent Claim
16 words
The integrated circuit as in claim 27 wherein said one plate is adjacent said second portion.
Claim 31
Dependent Claim
17 words
The integrated circuit as in claim 28 wherein a pass transistor is associated with said first portion.
Claim 32
Dependent Claim
16 words
The integrated circuit as in claim 25 wherein said one plate is adjacent said second portion.
Claim 33
Dependent Claim
17 words
The integrated circuit as in claim 25 wherein a pass transistor is associated with said first portion.
References Cited (Backward Citations)
US4104086A
Cited
US4635090A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-01-07 | 1994-07-09 | 1995-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-07 | 1998-07-09 | 1999-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-07 | 2002-07-09 | 2003-01-08 | $7700.00 | Window Closed / Lapsed |