Design verification for asymmetric phase shift mask layouts

摘要

A checking routine verifies a phase shifted mask (PSM) design based on fundamental principles of PSM and utilizing only basic shape manipulation functions and Boolean operations found in most computer aided design (CAD) systems. The design verification system checks complete chip designs for the two possible design errors that can cause defective masks by eliminating the phase transition; namely, placing a 180° phase region on both sides of a critical feature or completely omitting the phase region adjacent to certain critical features.