Lithographic apparatus, alignment system, and device manufacturing method
US7440079B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 22, 2005 |
| Grant date | Oct 21, 2008 |
| Priority date | — |
| Expiry date | Jan 12, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7092
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A lithographic apparatus according to one embodiment includes an alignment system for aligning a substrate. The alignment system comprises an illuminator system configured to illuminate an alignment mark on the substrate with an illumination spot, the alignment mark comprising a plurality of lines and spaces. The system also includes a combiner system configured to transfer two images of the illuminated alignment mark without spatial filtering of the images, rotate the images 180° relatively to each other, and combine the two images; and a detection system configured to detect an alignment signal from the combined images and to determine a unique alignment position by selecting a specific one of extreme values in the detected alignment signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.