With the introduction of ArF laser, its high photon energy affects the pellicle degradation in direct. The components
outgassed from the damaged pellicle have the effect on the CD variation of reticle. In order to resolve this new inevitable
problem, the method of dry gas purge has been proposed among the various solutions recently. Dry gas purge method is
generally applied to two applications. It can be applied to a storage environment such as reticle stocker, reticle SMIF pod
and reticle library in scanner and to the exposure chamber inside of a scanner during ArF laser exposure phase directly.
In this case, it is quite important technologically that which gas is determined as dry purge gas, pure nitrogen or CDA
(clean dry air). In this study, the effects of exposure environment on pellicle degradation according to dry purge gas and
their mechanism has been investigated to propose strategies and solutions of dry gas purge technology.
With the introduction of ArF laser, a binary mask is preferred because a PSM mask is still weak to the crystal defect
called as photomask haze although extensive studies trying to resolve the haze impact to a photomask have been
performed by various researchers in company and school. However, a new problem was happened after a binary mask
introduction that CD variation in an exposure shot is appeared and is gradually increased. And finally, CD variation
considerably causes defects in wafer level. It was proven that CD variation is closely related to the change of the reticle
transmittance by a lot of researches. In this study, the mechanism of ArF pellicle degradation is focused on because the
pellicle degradation affects a reticle transmittance in direct. The components outgassed from a pellicle by the high
photon energy of ArF laser, for example carbon or fluorine, are absorbed on the surface of the reticle, so that the
transmittance of the reticle is decreased. The phenomena of the pellicle degradation have been studied by the various
viewpoints, theoretical background, experiment and results tested in mass production line in this study. Therefore, this
study has the important meaning by providing the substantial clues to resolve CD variation problem in a near future.