Improved modeling of fogging and loading effect correction

The correction of fogging effect from an electron beam writer and loading effect from a dry etcher are known as the important factors of non-uniformity of mask CD. To achieve the improvement of CD uniformity, the fogging and loading effect are modeled as a function of pattern density. Taking into account the different behavior of fogging and loading effect on the pattern density, the amount of correction is able to be extracted using the promising modeling and dose modulation technique. In this work, we report the evaluation of correction method with improved model using the linear combination of fogging and loading effect. We compared the various cases and presented the best result of the improvement of CD uniformity.