Patent US5124216A successfully refreshed from Google Patents.
US5124216A
Expired / Lapsed
US
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Method for monitoring photoresist latent images
Assignee: Nokia Bell Labs
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Filing: 1990-07-31
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Granted: 1992-06-23
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Expires: 2010-07-31
Abstract
Abstract The formation of latent images in photoresist can be monitored during exposure without spurious images by directing a pulsed beam of monochromatic light onto a region of the layer being exposed and selectively detecting the diffracted light. Peak formation in the normalized diffracted intensity versus time curve indicates optimal exposure of the resist.
Inventors
- 👤 Konstantinos P. Giapis
- 👤 Richard A. Gottscho
- 👤 Christian A. Green
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 03:35
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70483; G03F7/7055; G03F7/70558; G03F7/20; G03F7/70605; G03F7/70653; G03F7/70675; G03F7/26; G03F7/30; G03F7/3021; G03F7/3028; Y; Y10; Y10S; Y10S430/00; Y10S430/146
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
99 words
A method for monitoring the formation of a latent image in a layer of photoresist comprising the steps of: providing a workpiece having a surface coated with photoresist; exposing said photoresist to form a latent image in a region thereof, during exposure directing onto said region of said photoresist a pulsed beam of monochromatic light having a duty cycle, beam cross section and beam intensity such that total exposure from said pulsed beam is less than would produce a developable image in the resist; and selectively detecting light from said pulsed beam diffracted from said region of said photoresist.
Claim 2
Independent Claim
99 words
A method for monitoring the formation of a latent image in a layer of photoresist comprising the steps of: providing a workpiece having a surface coated with photoresist; exposing said photoresist to form a latent image in a region thereof, during exposure directing onto said region of said photoresist a pulsed beam of monochromatic light having a duty cycle, beam cross section and beam intensity such that total exposure from said pulsed beam is less than would produce a developable image in the resist; and selectively detecting light from said pulsed beam diffracted from said region of said photoresist.
Claim 3
Dependent Claim
23 words
The method according to claim 1 wherein light from said pulsed beam is selectively detected only during periods when said beam is pulsing.
Claim 4
Dependent Claim
35 words
The method according to claim 1 wherein the energy per unit area of said pulsed beam of monochromatic light is less than 10% of the energy required to provide a developable image on said photoresist.
Claim 5
Dependent Claim
30 words
The method according to claim 1 wherein said latent image is formed by exposing said photoresist coated surface to a pattern of light by projecting ultraviolet light through a mask.
Claim 6
Dependent Claim
32 words
The method according to claim 1 wherein said latent image is formed by exposing said photoresist coated surface to a pattern of light by forming an interference pattern on said coated surface.
Claim 7
Dependent Claim
26 words
The method according to claim 5 further comprising the step of stopping formation of said latent image upon detection of said peak of diffracted light intensity.
Claim 8
Dependent Claim
26 words
The method according to claim 1 further comprising the step of detecting the occurrence of a peak of diffracted light intensity as a function of time.
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) | 1995-06-23 | 1995-12-23 | 1996-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-23 | 1999-12-23 | 2000-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-23 | 2003-12-23 | 2004-06-23 | $7700.00 | Window Closed / Lapsed |