ASYMMETRIC RETICLE HEATING OF MULTILAYER RETICLES ELIMINATED BY DUMMY EXPOSURES AND RELATED METHODS

Asymmetric heating and/or thermal expansion of a reticle or an image field is reduced. Embodiments include exposing a wafer with an actual image field (including a pattern for a chip layer) on a multilayer reticle, and performing a dummy exposure with another image field of the reticle. Other embodiments include exposing a wafer with a reticle area including both the actual and one or more other image fields of a multilayer reticle, sacrificing any die on the wafer that is exposed with substantial illumination with an image field other than the actual image field. Further embodiments include dummy exposures or enlargement of the illuminated reticle area of a single layer reticle with variation in pattern density between regions of the image field. Further embodiments include changing the image field geometry of a multilayer or single layer reticle.