Modifying Merged Sub-Resolution Assist Features of a Photolithographic Mask

Abstract

Modifying merged sub-resolution assist features includes receiving a mask pattern comprising the merged sub-resolution assist features, where a segmenting sub-resolution assist feature intersects a segmented sub-resolution assist feature at an intersection. Each sub-resolution assist feature is represented by an axis of the sub-resolution assist feature. The length of at least one axis is established, and an axis is modified in accordance with the length. Each axis is converted to a sub-resolution assist feature to yield the modified merged sub-resolution assist features.

1 - 18 . (canceled) 
   
   
       19 . A photolithographic mask, comprising:
 a substrate comprising a substantially transparent material; and   a layer disposed outwardly from the substrate, the layer patterned with a plurality of clear sub-resolution assist features comprising:
 a first sub-resolution assist feature comprising a first feature portion; and 
 a second sub-resolution assist feature comprising a second feature portion, the first feature portion substantially perpendicular to the second feature portion, a minimum distance between the first sub-resolution assist feature and the second sub-resolution assist feature approximately equal to a minimum spacing value. 
   
   
   
       20 . The photolithographic mask of  claim 19 , wherein the first sub-resolution assist feature has a substantially rectangular shape. 
   
   
       21 . The photolithographic mask of  claim 19 , wherein the first sub-resolution assist feature has a substantially L shape.