DIFFRACTION-BASED FOCUS METROLOGY

DIFFRACTION-BASED FOCUS METROLOGY

Diffraction-based focus target cells, targets and design and measurement methods are provided, which enable sensitive focus measurements to be carried out by overlay measurement tools. Cells comprise a periodic structure having a coarse pitch and multiple elements arranged at a fine pitch. The coars...

Ausführliche Beschreibung

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Bibliographische Detailangaben
1. Verfasser: LEVINSKI, Vladimir
Format: Patent
Sprache:eng ; fre ; ger
Schlagworte:
APPARATUS SPECIALLY ADAPTED THEREFOR
CINEMATOGRAPHY
ELECTROGRAPHY
HOLOGRAPHY
MATERIALS THEREFOR
ORIGINALS THEREFOR
PHOTOGRAPHY
PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES,e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTORDEVICES
PHYSICS
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Beschreibung
Zusammenfassung:Diffraction-based focus target cells, targets and design and measurement methods are provided, which enable sensitive focus measurements to be carried out by overlay measurement tools. Cells comprise a periodic structure having a coarse pitch and multiple elements arranged at a fine pitch. The coarse pitch is an integer multiple of the fine pitch, with the fine pitch being between one and two design rule pitches and smaller than a measurement resolution and the coarse pitch being larger than the measurement resolution. The elements are asymmetric to provide different amplitudes in +1st and −1st diffraction orders of scattered illumination, and a subset of the elements has a CD (critical dimension) larger than a printability threshold and the other elements have a CD smaller than the printability threshold.