US Patent 7531295 Method and apparatus for lithographic imaging using asymmetric illumination

According to one aspect of the present invention, a method and apparatus for processing a substrate may be provided. A reticle may be positioned relative to a substrate. The reticle may have a plurality of features with dimensions extending in a first and a second direction and being asymmetric in the first direction. Electromagnetic radiation may be directed onto the reticle. The electromagnetic radiation may have a first portion propagating onto the reticle in substantially the first direction and being incident on the reticle at a first angle and a second portion propagating onto the reticle in substantially the second direction and being incident on the reticle at a second angle. The second angle being greater than the first angle.