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 resist (CAR) process development is described. The method finds the optimal process conditions and the design center (maximum process tolerance space) of a CAR process with minimum experimental runs. First a modified response surface method is used to form the numerical response surface of a CAR, and its most sensitive point, which is the minimum requirement of X-ray dose, is located as an optimal process condition by an optimization method called POSM under the constraint of the contrast of the photoresist. Second, the design center is found to maximize the process tolerance space around the optimal process condition. Third, 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 example to show that the CARPOD method can identify the optimal process condition as well as the maximum tolerable parameter space with minimum experimental runs.