Patent US5164794A successfully refreshed from Google Patents.
US5164794A
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US
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Optical reticle inspection system and method
Assignee: Ultratech Inc
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Filing: 1991-07-15
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Granted: 1992-11-17
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Expires: 2011-07-15
Abstract
Abstract An optical reticle inspection system and method employing a photolithographic projection optical system. The present invention provides for imaging a reticle pattern to be inspected onto a complementary reticle pattern and directly viewing the obscured image pattern to provide a measure of the fidelity of the reticle patterns.
Inventors
- 👤 David A. Markle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:30
CPC Classifications
G; G01; G01B; G01B9/00; G01B9/08
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
80 words
A photolithographic projection optical system comprising: means for illuminating one-half of an optical field containing a first reticle pattern to be inspected, means for re-imaging light reflected from the entire reticle pattern onto the other half of said optical field containing a second complementary reticle pattern, and means for directly comparing or viewing the image of the first reticle pattern after being blocked by the second complementary pattern to provide a measure of the fidelity between said reticle patterns themselves.
Claim 2
Dependent Claim
80 words
A photolithographic projection optical system comprising: means for illuminating one-half of an optical field containing a first reticle pattern to be inspected, means for re-imaging light reflected from the entire reticle pattern onto the other half of said optical field containing a second complementary reticle pattern, and means for directly comparing or viewing the image of the first reticle pattern after being blocked by the second complementary pattern to provide a measure of the fidelity between said reticle patterns themselves.
Claim 3
Dependent Claim
19 words
A system as in claim 1 wherein photolithographic projection optical said system is a half field Dyson optical system.
Claim 4
Dependent Claim
15 words
A system as in claim 2 including detector array means for comparing said image patterns.
Claim 5
Dependent Claim
24 words
A system as in claim 1 where said means for illuminating is a dark field and comes from an annulus around a primary mirror.
Claim 6
Dependent Claim
81 words
In a photolithographic projection optical system, the method comprising the steps of: illuminating one-half of a projection system optical field containing a first reticle pattern to be inspected, re-imaging light reflected from the entire first reticle pattern onto the other half of said optical field containing a second complementary reticle pattern, and directly comparing or viewing the imagery patterns of said first pattern after superimposing on said complementary second pattern to provide a measure of the fidelity between said reticle patterns.
Claim 7
Dependent Claim
81 words
In a photolithographic projection optical system, the method comprising the steps of: illuminating one-half of a projection system optical field containing a first reticle pattern to be inspected, re-imaging light reflected from the entire first reticle pattern onto the other half of said optical field containing a second complementary reticle pattern, and directly comparing or viewing the imagery patterns of said first pattern after superimposing on said complementary second pattern to provide a measure of the fidelity between said reticle patterns.
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) | 1995-11-17 | 1996-05-18 | 1996-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-11-17 | 2000-05-18 | 2000-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-11-17 | 2004-05-18 | 2004-11-17 | $7700.00 | Window Closed / Lapsed |