1. A method, in a data processing system, for simultaneous optical proximity correction and decomposition, the method comprising: setting a first lithographic mask and a second lithographic mask equal to a target; performing simultaneous optical proximity correction and decomposition using the first lithographic mask and the second lithographic mask; and performing a first lithographic exposure with the first lithographic mask and performing a second lithographic exposure with the second lithographic mask to produce a final layout target closely resembling the original.