This paper proposes a best practice to produce the photomasks with the state-of-the-art quality, suitable for high resolution panel patterning. In order to extend the panel patterning process capability, high CD performance (Resolution, CD MTT and CD Uniformity) of photomask is essential and RET(Resolution Enhancement Technology) such as PSM, OPC and OAI will be prominent technology for mask business. PSM and OPC technology on RET will be new challenges for future high resolution panel. These challenges require new generation photomask writer, PSM manufacturing capability.