Methods for fabricating integrated circuits are provided. In one example, a method for fabricating an integrated circuit includes generating a photomask for forming a DSA directing pattern on a semiconductor substrate. The DSA directing pattern is configured to guide a self-assembly material deposited thereon that undergoes directed self-assembly (DSA) to form a DSA pattern. Generating the photomask includes, using a computing system, inputting a DSA target pattern. Using the computing system, a DSA model, an OPC model, and a MPC model, cooperatively running a DSA PC algorithm, an OPC algorithm, and a MPC algorithm to produce an output MPCed pattern for a mask writer to write on the photomask.