Method to determine the usefulness of alignment marks to correct overlay, and a combination of a lithographic apparatus and an overlay measurement system
US9454084B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 2013 |
| Grant date | Sep 27, 2016 |
| Priority date | — |
| Expiry date | Sep 15, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7046
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method to determine the usefulness of an alignment mark of a first pattern in transferring a second pattern to a substrate relative to the first pattern already present on the substrate includes measuring the position of the alignment mark, modeling the position of the alignment mark, determining the model error between measured and modeled position, measuring a corresponding overlay error between first and second pattern and comparing the model error with the overlay error to determine the usefulness of the alignment mark. Subsequently this information can be used when processing next substrates thereby improving the overlay for these substrates. A lithographic apparatus and/or overlay measurement system may be operated in accordance with the method.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.