Patent ID: 6901576
Filing Date: 2005-05-31
Classification: G03F

Abstract:
1. A method for designing an alternating phase shifting mask (altPSM), the mask including a substrate, the method comprising: a) providing a circuit layout; b) identifying a plurality of critical elements of said circuit layout; c) providing a cutoff layout dimension; d) identifying critical segments of the circuit layout wherein each of the plurality of critical elements has a sub-cutoff dimension less than said cutoff dimension; e) creating basic phase shapes associated with the critical segments; f) removing layout violations from the phase shapes; g) performing a test to determine whether the widths of phase shapes associated with a critical segment have unequal narrower and wider widths and if the test result is YES, then widening each narrower phase shape to match the width of wider phase shape associated with the critical segment and repeating steps (f) through (g) until the test results in a NO answer; and h) if the test result is NO, then providing a layout pattern to an output.