Development of an accurate empirical model for ArF lithography

“Dose-MEF” was measured on ArF and KrF resists. The “dose-MEF” is very important factor for mask making spec. Conventional lithography simulation such as “Diffused aerial image simulation” does not predict the ArF experimental value precisely. In order to explain the dose-MEF of ArF resist, we introduce intensity biasing. The intensity biasing is caused by flare of exposure tool and another mechanism. The intensity biasing reduces the dose-MEF. Small dose-MEF leads to the relaxed mask spec.