Enhanced illuminator for use in photolithographic systems

摘要

Methods and apparatus for enabling both isolated and dense patterns to be accurately patterned onto a wafer are disclosed. According to one aspect of the present invention, an illumination system that is suitable for use as a part of a projection tool includes an illumination source and an illuminator aperture. The illuminator aperture has a center point and an outer edge, and also includes a first pole and a second pole. The first pole is defined substantially about the center point, and the second pole is defined substantially between the first pole and the outer edge of the first pole. The illumination source is arranged to provide a beam to the illuminator aperture.