US4784719A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dry etching procedure
Assignee: Nokia Bell Labs
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Filing: 1988-01-19
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Granted: 1988-11-15
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Expires: 2008-01-19
Abstract
Abstract The presence of material deposited on the sidewall during device fabrication utilizing plasma-effected etching of semiconductor materials has significant consequences in the properties of these devices. It has been found that such depositions lead to a sidewall slope that, among other things, in turn produces linewidth loss. Additionally, the presence of a sloped masking material, e.g., a photoresist or sidewall deposit, produces further undesirable results.
Inventors
- 👤 Ronald J. Schutz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:05
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/24; H10P50/242; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/268; H10P50/69; H10P50/691; H10P50/693; H10P50/73
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
117 words
A process for fabricating a device comprising the steps of forming a resist mask on a substrate, etching said substrate to form a plurality of etch pits defining a plurality of features that are designed to have a desired linewidth by inducing reaction of said substrate with energetic species, and completing said device, wherein redeposition of material on the sidewalls of said etch pit occurs during said etching and wherein said process includes a step comprising locally compensating for the effect of said redeposition on the conformation of said sidewall by providing a processing environment for at least one of said features that differs from at least one of said features to aid in maintaining said linewidth.
Claim 2
Dependent Claim
117 words
A process for fabricating a device comprising the steps of forming a resist mask on a substrate, etching said substrate to form a plurality of etch pits defining a plurality of features that are designed to have a desired linewidth by inducing reaction of said substrate with energetic species, and completing said device, wherein redeposition of material on the sidewalls of said etch pit occurs during said etching and wherein said process includes a step comprising locally compensating for the effect of said redeposition on the conformation of said sidewall by providing a processing environment for at least one of said features that differs from at least one of said features to aid in maintaining said linewidth.
Claim 3
Dependent Claim
14 words
The process of claim 1 wherein said feature comprises a gate of a transistor.
Claim 4
Dependent Claim
17 words
The process of claim 1 wherein said commpensation comprises adjusting the local dimension of said resist mask.
Claim 5
Dependent Claim
22 words
The process of claim 1 wherein said compensation comprises forming a non-functional feature in proximity to at least one of said features.
Claim 6
Dependent Claim
30 words
The process of claim 1 wherein said compensation comprises diverting one of said features from a route of least meander to be in proximity with a second of said features.
Claim 7
Dependent Claim
10 words
The process of claim 1 wherein said substrate comprises silicon.
Claim 8
Dependent Claim
160 words
A process for fabricating a device comprising the steps of forming a resist mask on a substrate, etching said substrate to form a plurality of etch pits defining a plurality of features by inducing reaction of said substrate with energetic species, and completing said device, wherein redeposition of material on the sidewalls of said etch pit occurs during said etching and wherein said process includes a step comprising contacting, when said redeposited material presents a barrier to isotropic etching in said substrate, said etchant species with said resist mask so that the angle formed between a) a tangent to said resist mask at the point said resist mask intersects the substrate and b) a perpendicular to said substrate at said point is less than arctan ( y x ), where x is the horizontal rate of said redeposition at said point and y is the etch rate of said substrate whereby the linewidth defined by said mask is essentially maintained.
Claim 9
Dependent Claim
160 words
A process for fabricating a device comprising the steps of forming a resist mask on a substrate, etching said substrate to form a plurality of etch pits defining a plurality of features by inducing reaction of said substrate with energetic species, and completing said device, wherein redeposition of material on the sidewalls of said etch pit occurs during said etching and wherein said process includes a step comprising contacting, when said redeposited material presents a barrier to isotropic etching in said substrate, said etchant species with said resist mask so that the angle formed between a) a tangent to said resist mask at the point said resist mask intersects the substrate and b) a perpendicular to said substrate at said point is less than arctan ( y x ), where x is the horizontal rate of said redeposition at said point and y is the etch rate of said substrate whereby the linewidth defined by said mask is essentially maintained.
Claim 10
Dependent Claim
14 words
The process of claim 7 wherein said feature comprises a gate of a transistor.
Claim 11
Dependent Claim
10 words
The process of claim 7 wherein said substrate comprises silicon.
Claim 12
Dependent Claim
170 words
A process for fabricating a device comprising the steps of forming a resist mask on a substrate, etching said substrate to form a plurality of etch pits defining a plurality of features by inducing reaction of said substrate with energetic species, and completing said device, wherein redeposition of material on the sidewalls of said etch pit occurs during said etching and wherein said process includes a step comprising limiting, when said redeposited material presents a barrier to isotropic etching in said substrate, the contact angle between the momentum direction of said etchant species and a tangent to said redeposited material at all points on said resistant redeposited material serving to mask said sidewalls so that said contact angle is less than arctan ( z x ), where z is the etch rate of said resistant redeposited material in a direction parallel to said etchant species momentum direction and where x is the horizontal rate of deposition at said point whereby anisotropy is maintained without an excessive decrease in etch rate.
Claim 13
Dependent Claim
170 words
A process for fabricating a device comprising the steps of forming a resist mask on a substrate, etching said substrate to form a plurality of etch pits defining a plurality of features by inducing reaction of said substrate with energetic species, and completing said device, wherein redeposition of material on the sidewalls of said etch pit occurs during said etching and wherein said process includes a step comprising limiting, when said redeposited material presents a barrier to isotropic etching in said substrate, the contact angle between the momentum direction of said etchant species and a tangent to said redeposited material at all points on said resistant redeposited material serving to mask said sidewalls so that said contact angle is less than arctan ( z x ), where z is the etch rate of said resistant redeposited material in a direction parallel to said etchant species momentum direction and where x is the horizontal rate of deposition at said point whereby anisotropy is maintained without an excessive decrease in etch rate.
Claim 14
Dependent Claim
14 words
The process of claim 10 wherein said feature comprises a gate of a transistor.
Claim 15
Dependent Claim
10 words
The process of claim 10 wherein said substrate comprises silicon.
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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) | 1991-11-15 | 1992-05-16 | 1992-11-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-15 | 1996-05-16 | 1996-11-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-15 | 2000-05-16 | 2000-11-15 | $7700.00 | Window Closed / Lapsed |