Patent ID: 7175942
Filing Date: 2007-02-13
Classification: G03F

Abstract:
1. A method of designing a layout of an alternating phase shifting mask for projecting an image of an integrated circuit design comprising: providing a design of an integrated circuit layout having a plurality of features to be projected using alternating phase shifting segments, including a feature having a critical width along a length thereof that extends beyond another feature; providing alternating phase shift design rules based on alternating phase shift design parameters comprising minimum phase width, minimum phase-to-phase spacing, and minimum extension of critical width beyond another feature; identifying portions of the integrated circuit layout having a critical width feature that violate the alternating phase shift design rules; redesigning the critical width feature in the integrated circuit layout that violates the alternating phase shift design rules by reducing the length that the critical width feature extends beyond the other feature to the minimum extension; and generating an alternating phase shifting mask layout with the reduced length of the critical width feature in conformance with the alternating phase shift design rules.