Patent ID: 7361434
Filing Date: 2008-04-22
Classification: G03F

Abstract:
1. A phase shift mask for the projection of a pattern of structure elements formed on the mask onto a substrate, the phase shift mask comprising: a first portion of the pattern including a plurality of first structure elements formed as elevated ridges made from a semitransparent, phase-shifting material, which is arranged on a planar surface of a transparent mask substrate; and a second portion of the pattern being free of a phase shifting or semitransparent material, the second portion including a plurality of second structure elements formed by trenches with closely adjacent trench edges in the planar surface of the mask substrate with a depth, or formed by ridges with closely adjacent ridge edges within a surface etched with the depth into the surface of the mask substrate, such that a light beam transmitted through the mask substrate within the trenches or ridges experiences a phase shift of 180 +/−20 degrees with respect to a light beam transmitted through the mask substrate on the planar surface outside the trenches.