Measurement method, inspection apparatus, patterning device, lithographic system and device manufacturing method
US10691030B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 16, 2018 |
| Grant date | Jun 23, 2020 |
| Priority date | — |
| Expiry date | Nov 16, 2038 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/95
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A focus metrology target includes one or more periodic arrays of features. A measurement of focus performance of a lithographic apparatus is based at least in part on diffraction signals obtained from the focus metrology target. Each periodic array of features includes a repeating arrangement of first zones interleaved with second zones, a feature density being different in the first zones and the second zones. Each first zone includes a repeating arrangement of first features. A minimum dimension of each first feature is close to but not less than a resolution limit of the printing by the lithographic apparatus, so as to comply with a design rule in a given a process environment. A region of high feature density may further include a repeating arrangement of larger features.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.