US4880309A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dark field target design system for alignment of semiconductor wafers
Assignee: Ultratech Inc
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Filing: 1987-04-14
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Granted: 1989-11-14
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Expires: 2007-04-14
Abstract
Abstract A dark field target design system for alignment of semiconductor wafers is disclosed. The system utilizes improved target designs which provide for improvement in the alignment of semiconductor wafers.
Inventors
- 👤 Mark S. Wanta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 00:16
CPC Classifications
G; G03; G03F; G03F9/00; G03F9/70; G03F9/7069; G03F7/00; G03F7/70; G03F7/70216; G03F7/70358; G03F9/7073; G03F9/7076
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
99 words
A dark field wafer alignment system comprising means for exposing a plurality of reticle images in a step and repeat manner onto a semiconductor wafer, and means for aligning each reticle image to targets in the wafer scribe area wherein said means for aligning include alignment marks having a generally cross-shaped configuration of arms wherein each arm o said configuration is in the shape of a series of separate zigged shaped target structures so as to provide a sufficient edge length and surface area to reflect more light from the center of the target rather than the sides thereof.
Claim 2
Dependent Claim
99 words
A dark field wafer alignment system comprising means for exposing a plurality of reticle images in a step and repeat manner onto a semiconductor wafer, and means for aligning each reticle image to targets in the wafer scribe area wherein said means for aligning include alignment marks having a generally cross-shaped configuration of arms wherein each arm o said configuration is in the shape of a series of separate zigged shaped target structures so as to provide a sufficient edge length and surface area to reflect more light from the center of the target rather than the sides thereof.
Claim 3
Dependent Claim
16 words
The system as in claim 1 wherein the width of said target is approximately 5 microns.
Claim 4
Dependent Claim
98 words
In a dark field wafer alignment system for exposing a plurality of reticle images in a step and repeat manner onto a semiconductor wafer, the apparatus comprising means for aligning each reticle image to targets in the wafer scribe area wherein said means for aligning include alignment marks having a generally cross-shaped configuration of arms wherein each arm of said configuration is in the shape of a series of zigged shaped separate target structures to provide a sufficient edge length and surface area to reflect more light from the center of the target rather than the sides thereof.
Claim 5
Dependent Claim
98 words
In a dark field wafer alignment system for exposing a plurality of reticle images in a step and repeat manner onto a semiconductor wafer, the apparatus comprising means for aligning each reticle image to targets in the wafer scribe area wherein said means for aligning include alignment marks having a generally cross-shaped configuration of arms wherein each arm of said configuration is in the shape of a series of zigged shaped separate target structures to provide a sufficient edge length and surface area to reflect more light from the center of the target rather than the sides thereof.
Claim 6
Dependent Claim
16 words
The system as in claim 3 wherein the width of said targets is approximately five microns.
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) | 1992-11-13 | 1993-05-15 | 1993-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-13 | 1997-05-15 | 1997-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-13 | 2001-05-15 | 2001-11-14 | $7700.00 | Window Closed / Lapsed |