1. An apparatus for generating masks for printing a pattern comprising a plurality of features having varying critical dimensions, said apparatus comprising: means for obtaining data representing said pattern; means for defining a plurality of distinct zones based on the critical dimensions of said plurality of features; means for categorizing each of said features into one of said plurality of distinct zones; and means for modifying a mask having said pattern for each feature categorized into a predefined distinct zone of said plurality of distinct zones, wherein said plurality of distinct zones comprises: a first zone in which features having a critical dimension less than or equal to a first predetermined amount can be imaged utilizing chromeless phase lithography techniques; a second zone in which features having a critical dimension greater than said first predetermined amount and less than a second predetermined amount can be imaged utilizing a combination of chromeless phase lithography techniques and chrome; and a third zone in which features having a critical dimensions greater than said second predetermined amount can be imaged utilizing chrome.