Focus monitoring method, exposure apparatus, and exposure mask
US6701512B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 23, 2002 |
| Grant date | Mar 2, 2004 |
| Priority date | — |
| Expiry date | Aug 24, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70641
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
According to a focus monitoring method, an exposure mask on which a focus monitor pattern comprising at least two types of pattern groups is formed is prepared. A pattern group A of the at least two pattern groups is illuminated with illumination light while a barycenter of an illumination light source of illumination optics is in an off-axis state. At least a pattern group B of the at least two pattern groups is illuminated with illumination light while the barycenter of the illumination light source is in an on-axis state. A positional deviation between the pattern groups A and B transferred onto a substrate is measured. An effective focus position can be monitored from this positional deviation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.