Lithography Method and Structure for Resolution Enhancement with a Two-State Mask

摘要

A lithography process in a lithography system includes loading a mask that includes two mask states defining an integrated circuit (IC) pattern. The IC pattern includes a plurality of main polygons, wherein adjacent main polygons are assigned to different mask states; and a background includes a field in one of the mask states and a plurality of sub-resolution polygons in another of the two mask states. The lithography process further includes configuring an illuminator to generate an illuminating pattern on an illumination pupil plane of the lithography system; configuring a pupil filter on a projection pupil plane of the lithography system with a filtering pattern determined according to the illumination pattern; and performing an exposure process to a target with the illuminator, the mask, and the pupil filter. The exposure process produces diffracted light and non-diffracted light behind the mask and the pupil filter removes most of the non-diffracted light.

主权项

1. A lithography process in a lithography system, comprising:
loading a mask that includes two mask states defining an integrated circuit (IC) pattern, wherein the IC pattern includes
a plurality of main polygons, wherein adjacent main polygons are assigned to different mask states; anda background includes a field in one of the mask states and a plurality of sub-resolution polygons in another of the two mask states; configuring an illuminator to generate an illuminating pattern on an illumination pupil plane of the lithography system; configuring a pupil filter on a projection pupil plane of the lithography system with a filtering pattern determined according to the illumination pattern; and performing an exposure process to a target with the illuminator, the mask, and the pupil filter, wherein the exposure process produces diffracted light and non-diffracted light behind the mask and the pupil filter removes most of the non-diffracted light.