Patent ID: 6013397
Filing Date: 2000-01-11
Classification: G03F

Abstract:
A method using an original pattern for automatically forming a sub-resolution phase shifting mask (PSM), the method comprising:forming a shielding layer on a transparent substrate;forming a first photoresist layer with a pattern over the shielding layer;etching the shielding layer, using the first photoresist layer as an etching mask, to form the original pattern and an assist feature around the original pattern, wherein the assist feature is separated from the original pattern by a distance;removing the first photoresist layer;forming a second photoresist layer over the substrate so as to expose a phase shifting region, which comprises the original pattern, an exposed portion of the substrate between the original pattern and the assist feature, and a portion of the assist feature;etching the exposed portion of the substrate, using the second photoresist layer as an etching mask, so as to form a phase shifting layer in the substrate; andremoving the second photoresist layer so that the substrate comprises the phase shifting region and a normal region other than the phase shifting region.