Impact Of Illumination On Model-Based SRAF Placement For Contact Patterning

Sub-Resolution Assist Features (SRAFs) have been used extensively to improve the process latitude for isolated and semi-isolated features in conjunction with off-axis illumination. These SRAFs have typically been inserted based upon rules which assign a global SRAF size and proximity to target shapes. Additional rules govern the relationship of assist features to one another, and for random log... » read more