Lithographic method using double exposure techniques, mask position shifting and light phase shifting

摘要

A lithographic method using double exposures, physical mask shifting, and light phase shifting is used to form masking features on a substrate masking layer. A first phase shifting mask (11) is placed in a first position adjacent a substrate (10). The substrate (10) is covered by the masking layer. The masking layer is exposed to light, or an equivalent energy source, through the first mask (11) to form a first plurality of unexposed regions of the masking layer. Either a second mask or the first mask (11) is placed adjacent the substrate (10) in a second position which is displaced from the first position in an X direction, a Y direction, and/or a rotational direction. A second exposure is used to form a second plurality of unexposed regions of the masking layer. The first and second pluralities of unexposed regions have common unexposed regions which are used to form the masking features.