PELLICLE FILM AND EXPOSURE METHOD USING SAME

摘要

PROBLEM TO BE SOLVED: To obtain a pellicle film excellent in transmittance to F2 laser light (157 nm), less liable to its thickness reduction owing to photodegradation and having excellent light resistance and excellent transmittance in a pellicle used for protecting a photomask from dust in lithography using a very short- wavelength light source for exposure such as F2 laser (157 nm). SOLUTION: The pellicle film consists of an organic polymer having units (A) of tetrafluoroethylene and units (B) of cyclic perfluoro-ether and satisfying the relation of 0.7<=n/(m+n)<=1 between the number (m) of moles of the unit A and the number (n) of moles of the unit B and has >=90% transmittance at 157 nm wavelength.