A method for performing OPC and evaluating OPC solutions is disclosed. An exemplary method includes receiving a design database corresponding to an IC circuit mask. A first lithography simulation and evaluation is performed on the design database utilizing a first set of performance indexes. A modification is made to the design database based on a result of performing the first lithography simulation and evaluation. A second lithography simulation and evaluation is performed on the design database utilizing a second set of performance indexes to verify the modification. If necessary, the design database is modified again based on a result of the second lithography simulation and evaluation. The modified design database is provided to a mask manufacturer for manufacturing the mask corresponding to the modified design database.