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US5201993A
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Anisotropic etch method
Assignee: Micron Technology Inc
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Filing: 1990-08-27
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Granted: 1993-04-13
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Expires: 2010-08-27
Abstract
Abstract A method to anisotropically etch an oxide/silicide/poly sandwich structure on a silicon wafer substrate in situ, that is, using a single parallel plate plasma reactor chamber and a single inert cathode, with a variable gap between cathode and anode. This method has an oxide etch step that utilizes C 2 F 6 , CF 4 , CHF 3 and an inert carrier gas as the etching atmosphere. The fully etched sandwich structure has a vertical profile at or near 90° from horizontal, with no bowing or notching.
Inventors
- 👤 Rod C. Langley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:39
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/013; H10D64/01302; H10D64/01304; H10D64/01322; H10P; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/268; H10P50/28; H10P50/282; H10P50/283
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
100 words
A method of anisotropically etching dielectric layer on a substrate, comprising the steps of: a) providing a parallel plate plasma etch reactor, having a first electrode whereupon the substrate is mounted, and having a second electrode that is non-erodible by plasma; b) providing an atmosphere within said reactor, consisting essentially of C 2 F 6 , CHF 3 , CF 4 , and an inert carrier gas, whereby said atmosphere contains more C 2 F 6 than CF 4 , and more CF 4 than CHF 3 ; c) exposing the dielectric layer to a plasma maintained in said atmosphere.
Claim 2
Independent Claim
100 words
A method of anisotropically etching dielectric layer on a substrate, comprising the steps of: a) providing a parallel plate plasma etch reactor, having a first electrode whereupon the substrate is mounted, and having a second electrode that is non-erodible by plasma; b) providing an atmosphere within said reactor, consisting essentially of C 2 F 6 , CHF 3 , CF 4 , and an inert carrier gas, whereby said atmosphere contains more C 2 F 6 than CF 4 , and more CF 4 than CHF 3 ; c) exposing the dielectric layer to a plasma maintained in said atmosphere.
Claim 3
Dependent Claim
84 words
The method of claim 1, wherein: a) said atmosphere has a pressure of approximately 2.3 torr and includes approximately 50 sccm C 2 F 6 , approximately 32 sccm CHF 3 , approximately 40 sccm CF 4 , and approximately 100 sccm He as its inert carrier gas; b) a power density of said plasma is approximately 1.9 W/cm 2 ; c) a gap of approximately 0.48 cm exists between said first and second electrodes; and d) said non-erodible second electrode is anodized aluminum.
Claim 4
Dependent Claim
58 words
The method of claim 1, wherein: a) said atmosphere has a pressure of approximately 1.8 to 3.0 torr; b) a power density of said plasma is approximately 0.18 to 4.0 W/cm 2 ; c) a gap of approximately 0.3 to 0.6 cm exists between said first and second electrodes; and d) said non-erodible second electrode is anodized aluminum.
Claim 5
Dependent Claim
57 words
The method of claim 1, wherein: a) said atmosphere has a pressure of approximately 2.2 to 2.4 torr; b) a power density of said plasma approximately 0.18 to 4.0 W/cm 2 ; c) a gap of approximately 0.38 to 0.52 cm exists between said first and second electrodes; and d) said non-erodible second electrode is anodized aluminum.
Claim 6
Dependent Claim
20 words
The method of claim 1, wherein said atmosphere includes at least approximately 5 sccm He as its inert carrier gas.
Claim 7
Independent Claim
160 words
A method of anisotropically etching a dielectric layer on a substrate wafer, comprising the steps of: a) providing a parallel plate plasma etch reactor, having a first electrode whereupon the substrate wafer is mounted, and having a second electrode that is non-erodible by plasma; b) providing an atmosphere within said reactor, consisting essentially of C 2 F 6 , CF 4 , CHF 3 and an inert carrier gas, said atmosphere containing more C 2 F 6 than CF 4 and more CF 4 than CHF 3 , and having a pressure of approximately 1.8 to 3.0 torr; c) performing a plasma etch step in the reactor, with C 2 F 6 in the atmosphere as the predominant gas, thereby providing more CF X species than F radials and relatively few fluorine radicals, and reducing micromasking on the wafer; and d) exposing the dielectric layer to a plasma having a power density of approximately 0.18 to 4.0 W/cm 2 .
Claim 8
Independent Claim
160 words
A method of anisotropically etching a dielectric layer on a substrate wafer, comprising the steps of: a) providing a parallel plate plasma etch reactor, having a first electrode whereupon the substrate wafer is mounted, and having a second electrode that is non-erodible by plasma; b) providing an atmosphere within said reactor, consisting essentially of C 2 F 6 , CF 4 , CHF 3 and an inert carrier gas, said atmosphere containing more C 2 F 6 than CF 4 and more CF 4 than CHF 3 , and having a pressure of approximately 1.8 to 3.0 torr; c) performing a plasma etch step in the reactor, with C 2 F 6 in the atmosphere as the predominant gas, thereby providing more CF X species than F radials and relatively few fluorine radicals, and reducing micromasking on the wafer; and d) exposing the dielectric layer to a plasma having a power density of approximately 0.18 to 4.0 W/cm 2 .
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-04-12 | 1996-10-12 | 1997-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-04-12 | 2000-10-12 | 2001-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-04-12 | 2004-10-12 | 2005-04-13 | $7700.00 | Window Closed / Lapsed |