1. An optical proximity correction (OPC) method, comprising the steps of: providing original design patterns; grouping the original design patterns into a first group and a second group, wherein each pattern of the first group has a size larger than a size of any pattern of the second group; establishing a simple OPC model for patterns of the first group using a relatively small number of convolution kernels; establishing a complex OPC model for patterns of the second group using a relatively great number of convolution kernels; combining the simple and complex OPC models to generate a hybrid OPC model; and performing an OPC treatment on the original design patterns based on the hybrid OPC model.