Optimized optical parameters can enhance the performance of resist systems. Expanded process latitudes can be achieved through the manipulation of the optical levers on a variable parameter stepper, extending a resist system's capability over a wider range of applications. In this study, the parameters being examined are numerical aperture, partial coherence and annularity. A 33 experiment of the optical factors was performed to screen for interactions between factors and to establish a resist model which can characterize behavior over the design space. Responses include energy to clear (Eo), sizing energy (Es), sizing ratio (Es/Eo), Iso/Dense bias, masking linearity, resolution, exposure latitude, focus latitude, and feature profile. Equations are presented to predict resist performance of selected responses for dense lines/spaces, isolated lines, trenches and contact holes. Optical parameter combinations are cited to optimize performance of individual features.