Fundamental study on the error factor for sub 90 nm OPC modeling

In low-k1 imaging lithography process it is difficult to make the accurate OPC model not only because of factors caused by unstable process such as large CD (Critical Dimension) variation, large MEEF (Mask Error Enhancement Factor) and very poor process window but also because of potential error factors induced during OPC model fitting. In order to minimize those issues it is important to reduce the errors during OPC modeling. In this study, we have investigated the most influencing error factors in OPC modeling. At first, through comparing influence of optical parameters and illumination systems on OPC runtime and model accuracy, we observe main error factor. Secondly, in the case of resist modeling, OPC runtime and model accuracy were also analyzed by various model forms.