Phase shift mask (PSM) with optical proximity effect correction (OPC) is the efficient tool of the resolution enhancement technology (RET). Particularly, it is commonly known that the attenuated PSM(att.PSM) has some merits in the memory device with a repeated cell patterns. But there are only a few results of what illumination systems affect the performance of the attPSM and how much the transmittance of the attPSM affects the lithography performance -- such as resolution and depth of focus. In this paper, we will present the optimized illumination systems for patterning with the attPSM, and the relationship between the transmittance of the attPSM and the lithography performance by using simulations and experiments. The resolution of KrF lithography with the Hi-T att.PSM can be extended to 130 nm through the simulation. We extend the resolution of KrF lithography with the Hi-T att.PSM to 150 nm through the experiment.