Dyiann Cho, Mentor Graphics
Ken McAllister, Infineon Technologies

In this paper, several approaches related to OPC are studied on poly layer, in terms of line end bridging margin and line end shortening, to optimize line end performance. The OPC minimum external constraint is optimized to meet both line end bridging and shortening requirements. Serif type line end provides the OPC model with more flexibility to pull back the center segment between line end serifs and improves the bridging margin by 2%, with negligible sacrifice on line end length under overexposure conditions. No effect is seen on the bridging margin with different segment lengths of center pull back at the serif line end. Bridging margin can be improved dramatically (6%) by adding SRAF, due to the increase of aerial image intensity in the line end space. Finally, the OPC model fitting for line end shortening is briefly described and a post-correction rule-based OPC is introduced to improve the line end shortening. Handcrafted OPC is also used for this case study for few structures that need extra correction to achieve enough line end length.