US4552831A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fabrication method for controlled via hole process
Assignee: International Business Machines Corp
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Filing: 1984-02-06
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Granted: 1985-11-12
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Expires: 2004-02-06
Abstract
Abstract A method for forming via holes having a rounded sidewall profile includes exposing a layer or organic positive photoresist to a formic gas plasma while the surface of the photoresist layer is bombarded with ions and electrons in a high voltage biased environment in which the photoresist layer is capacitively coupled. The photoresist layer may be exposed to UV light either before or after the formic gas plasma step.
Inventors
- 👤 Cheng-Yih Liu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:02
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/26; G03F7/38; H; H05; H05K; H05K3/00; H05K3/0011; H05K3/0017
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
90 words
A method for forming via holes having a rounded sidewall profile comprising the steps of: providing a layer of organic positive photoresist on the insulation layer, exposing said photoresist layer to a formic gas plasma, bombarding the surface of said photoresist layer with ions and electrons in a high voltage biased environment in which said photoresist layer is capacitively coupled whereby the solubility of the upper portion of said photoresist layer in a developer solution is increased, imagewise exposing said photoresist layer to UV light, and developing said photoresist layer.
Claim 2
Independent Claim
90 words
A method for forming via holes having a rounded sidewall profile comprising the steps of: providing a layer of organic positive photoresist on the insulation layer, exposing said photoresist layer to a formic gas plasma, bombarding the surface of said photoresist layer with ions and electrons in a high voltage biased environment in which said photoresist layer is capacitively coupled whereby the solubility of the upper portion of said photoresist layer in a developer solution is increased, imagewise exposing said photoresist layer to UV light, and developing said photoresist layer.
Claim 3
Dependent Claim
28 words
A method as described in claim 1 whereby the step of imagewise exposing said photoresist layer to UV light is carried out before the formic gas plasma step.
Claim 4
Dependent Claim
16 words
A method as described in claim 1 whereby said organic positive photoresist is of the AZ-type.
Claim 5
Dependent Claim
24 words
A method as described in claim 1 whereby said photoresist layer is exposed for 10 to 60 seconds to the ion and electron bombardment.
Claim 6
Dependent Claim
24 words
A method as described in claim 1 whereby said photoresist layer is exposed for 15 to 25 seconds to the ion and electron bombardment.
Claim 7
Dependent Claim
15 words
A method as described in claim 1 whereby the voltage is 50 to 2000 volts.
Claim 8
Dependent Claim
15 words
A method as described in claim 1 whereby the voltage is 300 to 400 volts.
References Cited (Backward Citations)
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Cited
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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) | 1988-11-11 | 1989-05-13 | 1989-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-11-11 | 1993-05-13 | 1993-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-11-11 | 1997-05-13 | 1997-11-12 | $7700.00 | Window Closed / Lapsed |