Advanced New Opc Method to Improve Opc Accuracy for Sub-90nm Technology

OPC has become an indispensable tool used in deep sub-wavelength lithograph process enabling highly accurate CD (Critical Dimension) control as design rule shrinks. Rule based OPC was widely acceptable in the past, however it has recently turned toward model OPC according to the decreasing pattern size. Model based correction was first applied to the optical proximity phenomenon because the image of sub-wavelength pattern is distorted severely during the optical image transformation. In addition, more tight CD control required to compensate the process induced error effects from etch or other process as well optical image can be achieved.In this paper, we propose advanced OPC method to obtain better accuracy on the final target for sub-90nm technology. This advanced method converts measured CD data into final CD target by using an equation. We compared the results from the data converting method, suggested in this paper, with those from post-litho(DI), post-etch (FI) OPC model step by step. Finally we confirmed that advanced new OPC method gives better accuracy than that from conventional OPC model.