This paper shows the capability of chromeless phase lithography (CPL) and is particularly focused on different strategies for optical proximity corrections (OPC). A chromeless phase database is easily obtained from the original layout by changing the chromium pattern into a phase pattern. However, a specific optical proximity correction has to be applied due to the phase effect and the high transmission of the mask. Mask Error Enhancement Factor (MEEF) and process window for CPL technology have been estimated through wafer exposures. Moreover, various optical proximity correction strategies have been explored through a comparison between phase and chromium features such as hammerhead, zebra and scattering bars 1,2. Indeed, depending on the density of the pattern, we can improve the contrast and the process window by changing the local transmission. The transmission can be controlled by the addition of sub resolution chromium feature such as zebra chromium transverse features on the line for dense pattern, or chromium scattering bars in the space for a sparse pattern, or chromium patches on the line end. From 65 nm node measurements and 45 nm node simulations, the authors will then present the most effective sub resolution pattern to implement.