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The amount of sulfate ion on mask surface will increase haze defect growing once exposed by an ArF
laser. And then the storage conditions influence amount of sulfate ion was investigated. Therefore, our
evaluations used extraction method and IC (Ion Chromatography) test to examine the amount of ions for
current mask pods and storage cabinet. The pods included the different material of ABS (Amber and Violet
Acrylonitrile Butadiene Styrene), PMMA (Polymethyl meth acrylate), PEEK (Polyether ether ketone),
Metal case, LCP (Liquid Crystal Plastic), PC+CF (Polycarbonate with carbon fiber) and PC+CNT
(Polycarbonate with Carbon nano-tubes). Moreover, PSM (Phase shift Mask) haze life time and dosage
was strongly interrelated with the amount of chemical contaminant aggregation for storage pods. The other
factor to impact haze generation of ArF PSM masks is the condition of storage environment; therefore, we're
comparing the different structure of cabinet from different vendors to extend mask life time. They included 3
types of storage system: cabinet with XCDA, purge cabinet and purge stocker. According to this point of
view, we used the impinger and Cr Blank IC test to verify the best storage system and remove some of the
polluted parts for cabinet to ensure haze free. Resulting from our investigations, we setup storage BKM
(Best Known Method) and monitor haze performance to record their results. Consequently, the optimization
components of storages will contribute the enormously economical benefit.
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