Patent ID: 6692878
Filing Date: 2004-02-17
Classification: G03F

Abstract:
An apparatus, comprising:a lithographic tool equipped with a mask in order to expose a wafer to patterned light, said mask comprising: a transparent layer that allows light to pass through said mask to said wafer; an opaque layer that thwarts the passing of light through said mask to said wafer; a range of metro cell edge slopes that help form a plurality of metro cells; an active device area, said active device area having a range of feature edge slopes, said plurality of metro cells used to help align said active device area within said photolithographic tool; and a region outside said active device area, said range of metro cell edge slopes at or within said range of feature edge slopes at least in part because said region sufficiently deterred etch rate reduction of a plasma etch used to form said metro cell edge slopes, said etch rate reduction caused by reactions between said plasma and a resist layer that existed on said mask outside said active device area during said plasma etch, said region exposing said opaque layer to said plasma during said plasma etch.