Alignment mark deformation estimating method, substrate position predicting method, alignment system and lithographic apparatus
US8982347B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 2, 2012 |
| Grant date | Mar 17, 2015 |
| Priority date | — |
| Expiry date | Apr 18, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7049
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method is used to estimate a value representative for a level of alignment mark deformation on a processed substrate using an alignment system. The alignment sensor system is able to emit light at different measuring frequencies to reflect from an alignment mark on the substrate and to detect a diffraction pattern in the reflected light in order to measure an alignment position of the alignment mark. The two or more measuring frequencies are used to measure an alignment position deviation per alignment mark associated with each of the two or more measuring frequencies relative to an expected predetermined alignment position of the alignment mark. A value is determined representative for the spread in the determined alignment position deviations per alignment mark in order to estimate the level of alignment mark deformation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.