METHOD OF MAKING AN INTEGRATED CIRCUIT USING A PHOTOMASK HAVING A DUAL ANTIREFLECTIVE COATING

摘要

A wafer (18) is made using a mask (14) that has a quartz substrate (15) and a patterned stack (32) for providing a mask pattern. The patterned stack comprises an opaque layer (36) between two ARC layers (34, 38). The patterned stack reduces flare, which in turn improves critical dimension (CD) control. The stack reduces the reflections that come from the interface between the opaque layer (36) and quartz substrate (15). This stack also absorbs the reflections that come back from the direction of the wafer. The opaque layer (36) is silicon, which is opaque at wavelengths below 300 nanometers, and the ARC layers are non-stoichiometric silicon nitride.