US6063530A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control of critical dimensions through measurement of absorbed radiation
Assignee: Polaris Innovations Ltd
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Filing: 1997-06-23
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Granted: 2000-05-16
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Expires: 2017-06-23
Abstract
Abstract A lithographic system with improved control of critical dimensions (CD). The lithographic system includes a detector for determining the amount of energy absorbed by the photoresist. This enables the lithographic system to expose each field with the required exposure dose, thus reducing variations in CD.
Inventors
- 👤 Andreas Grassmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:32
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70483; G03F7/20
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
173 words
A method for transferring a mask pattern to a photoresist layer, comprising: illuminating a mask comprising the mask pattern with radiation from an exposure source to create an image of the mask pattern; projecting the image onto a photoresist layer; detecting an amount of radiation absorbed by the photoresist layer; terminating the radiation to the photoresist at a time T when the amount of energy absorbed by the photoresist layer exceeds a threshold level; and wherein the detecting the amount of radiation absorbed by the photoresist layer comprises: measuring the intensity, I intensity , of incident radiation from the exposure source on the photoresist layer and integrating such measured intensity, I intensity , in accordance with ##EQU2## where t is time; measuring the intensity, I reflected , of a portion of the incident radiation that is reflected radiation from the photoresist layer and integrating such measured intensity, I reflected , in accordance with; ##EQU3## taking the difference of; ##EQU4## and terminating the exposure at the time T in accordance with the determined difference.
Claim 2
Independent Claim
173 words
A method for transferring a mask pattern to a photoresist layer, comprising: illuminating a mask comprising the mask pattern with radiation from an exposure source to create an image of the mask pattern; projecting the image onto a photoresist layer; detecting an amount of radiation absorbed by the photoresist layer; terminating the radiation to the photoresist at a time T when the amount of energy absorbed by the photoresist layer exceeds a threshold level; and wherein the detecting the amount of radiation absorbed by the photoresist layer comprises: measuring the intensity, I intensity , of incident radiation from the exposure source on the photoresist layer and integrating such measured intensity, I intensity , in accordance with ##EQU2## where t is time; measuring the intensity, I reflected , of a portion of the incident radiation that is reflected radiation from the photoresist layer and integrating such measured intensity, I reflected , in accordance with; ##EQU3## taking the difference of; ##EQU4## and terminating the exposure at the time T in accordance with the determined difference.
References Cited (Backward Citations)
US5124216A
Cited
US5674652A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-05-16 | 2003-11-15 | 2004-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-05-16 | 2007-11-15 | 2008-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-05-16 | 2011-11-15 | 2012-05-16 | $7700.00 | Window Closed / Lapsed |