Curvilinear mask is getting more widely used as a key technique for resolution enhancement with the progress of feature size shrinkage and multi-beam mask writers (MBMW) adoption. However, it is challenging to print curvilinear pattern accurately, which makes mask process correction (MPC) indispensable for curvilinear mask data preparation. It is known that pattern fidelity degrades at high curvature region by process blur. This degradation leads to various issues such as curvature loss and poor CD quality on printed curvilinear masks. Furthermore, due to anamorphic lithography systems, high-NA mask data is likely to contain patterns with higher curvatures compared to 0.33NA mask. Therefore, improving the accuracy of MPC on high curvature region is becoming more important. In this paper, we present a novel MPC method which deforms shape of high curvature region of any curvilinear pattern aggressively to achieve good fidelity. Using simulation and printed results of ellipse patterns with various curvatures, we will show that this MPC technique can improve pattern fidelity in regions of high curvature.
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