AN OPTIMIZATION DESIGN METHOD FOR CHEMICALLY AMPLIFIED RESIST PROCESS-CONTROL

A novel optimization method called chemically-amplified resist process optimization design (CARPOD) applicable to the chemically amplified r esist (CAR) process development is described. The method finds the opt imal process conditions and the design center (maximum process toleran ce space) of a CAR process with minimum experimental runs. First a mod ified response surface method is used to form the numerical response s urface of a CAR, and its most sensitive point, which is the minimum re quirement of X-ray dose, is located as an optimal process condition by an optimization method called POSM under the constraint of the contra st of the photoresist. Second, the design center is found to maximize the process tolerance space around the optimal process condition. Thir d, verifications are made on the optimal design as well as the design center. The process optimization of AZ PF-514 has been used as an exam ple to show that the CARPOD method can identify the optimal process co ndition as well as the maximum tolerable parameter space with minimum experimental runs.