Aggressive optical proximity correction method

摘要

A method of modifying a photo mask pattern by using computer aided design (CAD) is described. The photo mask pattern is used to manufacture a photo mask for transferal to a photoresist layer formed on a surface of a semiconductor wafer so as to form a predetermined original pattern. A first modification is first performed according to an optic proximity effect, and then a second modification is performed according to a line end shortening effect. The present invention prevents the line end shortening effect from occurring in a subsequent trim down etching process of the original pattern performed for reducing its critical dimension.