Improved baking of photomasks by a dynamically zone-controlled process approach

A new type of bake system for photomasks, APB5000, has been developed, using a dynamic and multiple zone approach, to enable more precise Post Exposure Bake (PEB) and Post Coat Bake (PCB) of conventional and chemically amplified resists (CAR). The principal equipment concept and the optimization strategies are presented. The baking performance of the APB5000 is demonstrated for several surface temperatures between 90 degree(s)C and 150 degree(s)C. The temperature uniformity ranges achieved at the resist plane are better than 0.25 degree(s)C after stabilization at the final temperature and better than 1.5 degree(s)C during the ramping period. The repeatability of the bake temperature is better than +/- 0.07 degree(s)C for the setpoint temperature.