A method, program product and apparatus of simultaneous optimization for na-sigma exposure settings and scattering bars opc using a device layout

Disclosed is a method, program product and apparatus for optimizing numerical aperture ("NA") and sigma of a lithographic system based on the target layout. A pitch or interval analysis is performed to identify the distribution of critical pitch over the design. Based on the pitch or interval analysis, a critical dense pitch is identified. NA, sigma-in, sigma-out parameters are optimized such that the critical feature will print with or without bias adjustment. For features other than the critical dense features, adjustments are made in accordance with OPC, and lithographic apparatus settings are further mutually optimized. Accordingly, lithographic apparatus settings may be optimized for any pattern concurrently with OPC.