A hybrid PPC method based on the empirical etch model for the 0.14μm DRAM generation and beyond

The hybrid PPC (process proximity correction) has been one of the inevitable methods for the sub-wavelength lithography to satisfy the requirements of CD control and yield improvement. In this paper, an effective methodology for hybrid PPC is presented to reduce the data volume and the complexity of patterns and to enhance the accuracy of correction. The selective engine in the flow of hybrid PPC classifies the gate patterns into the areas of model-based and rule-based PPC considering a device performance, a model accuracy, and the extension of the contact overlap margin. Furthermore, the effective method of an empirical model is exploited to compensate the nonlinear etch proximity effect. The statistical method based on the real pattern geometry is also constructed to reflect the process issues in real manufacturing. From this work with the 1 nm correction grid, 22% of the additional reduction in the intra-die CD variation compared with the rule-based PPC has been achieved.