It was demonstrated that optical lithography simulations can be used very effectively for broadband application and they are not the forte of I-line lithography. PROLITH simulator was used to optimize the photo process on Ultratech 1500 broadband stepper. More than 40 process variables were required to customize the software for this process. To do a broadband simulation the optical parameters of photoresist should be measured accurately on multiple wavelengths. This information not always available from photoresist vendors and often tedious to obtain by means of UV spectroscopy. To do the final tune up the resist exposure rate C was scaled by the same factor N within the entire illumination range of 380-450 nm to match the experimental Dose-to-clear value E. Good agreement with experimental data was achieved on different device layers. Process window for the critical geometry was calculated based on the linewidth and sidewall angle specifications. Better understanding of the process allowed us to qualify new process into production in very short time frame and saved a lot of test wafers. Further process optimization is under way and efforts are being made to identify the optimum process for the future devices with smaller CDs.