Feed-forward lithographic overlay offset method and system

A method and system embodying the present invention for predicting systematic overlay affects in semiconductor lithography. This method is a feed-forward method, based on correlation of current and prior aligned levels, to predict optimum overlay offsets for a given lot. Instead of using population...

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Bibliographische Detailangaben
Hauptverfasser:	PARRISH CHARLES J, CONRAD EDWARD W, WHITING CHARLES A
Format:	Patent
Sprache:	eng
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:	A method and system embodying the present invention for predicting systematic overlay affects in semiconductor lithography. This method is a feed-forward method, based on correlation of current and prior aligned levels, to predict optimum overlay offsets for a given lot. Instead of using population averaging, which ignores process variability, it acknowledges the variability and uses prior measurements to advantage. The principle, backed by production data, is that "systematic" overlay errors are just that: Image placement errors which persist through processing and will be predictable through time and processing.