Process for observing overlay errors on lithographic masks
US6489068B1 · kind B1 · utility
63Cited by
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20Claims
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Assignee
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Key dates
| Filing date | Feb 21, 2001 |
| Grant date | Dec 3, 2002 |
| Priority date | — |
| Expiry date | Feb 21, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70633
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of observing overlay errors associated with two masks or reticles includes providing alignment marks to a substrate. The alignment marks can be observed to determine overlay errors. In one embodiment, the lightness or darkness of the alignment marks can indicate an overlay error. The technique can be utilized in any photolithographic system including an EUV, VUV, DUV or conventional patterning device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.