Effects of 3D Profiles of Adjacent Trench Areas on Rule-Based Etch Bias Retargeting Accuracy for OPC

The shrinkage of critical lithographic feature size keeps introducing new challenges to the standard rule-based etch bias retargeting of Optical Proximity Corrections (OPC). This motivates the use of model-based instead of conventional rule-based etch bias retargeting. On the other hand, model-based retargeting comes with a substantial increase in run-time and complexity. Consequently, pushing the limits of rule-based retargeting can be an optimized solution to that problem [1]. Metrology data of OPC test patterns has always been the base for OPC etch bias rule-based retargeting tables. The accuracy and repeatability of that data is a key factor in the quality of OPC applied. In this work, a comprehensive study of the OPC test patterns is carried out for cross-sections of a substrate active layer for a 110nm node Shallow Trench Isolation (STI)/ Deep Trench Isolation (DTI) technology. We aim at a more reliable understanding of 3D profile effects on the active top of the silicon substrate. Coupled with the standard metrology data, our protocol would lead to a more accurate OPC etch bias rule-based retargeting.