Evaluating films for high transmission attenuated phase shift masks

Three types of high transmission attenuated phase shift masks were evaluated. The attenuating materials were obtained from commercial and non-commercial sources. Various key performance metrics were investigated. Blanket film transmission and reflection was measured at various wavelengths. Laser durability and cleaning durability were measured. Standard dry etch processes were used for each film and the profile and surface properties were compared. Final mask transmission and phase were also measured. The summarized results show clear benefits of using some high transmission materials relative to others.