Photomask blank shelf-life study on e-beam chemically amplified resists

Fabrication of 130nm and below technology node photomasks favors EBeam chemically amplified resist (CAR) due to its higher sensitivity, contrast and resolution. However, chemically amplified resist is in general much more sensitive to the environment compared to conventional resists such as PBS and ZEP7000. Coated CAR blank shelf life will have a major impact on CD control of high-end photomask manufacturing especially for extended delay situations. This paper presents blank supplier packaging methods and rawstock storage conditions and their impact on CAR blank shelf life in the photomask fabrication facility. We selected one of the top chemically amplified e-beam resists for this study.