Ion exchange resin treatment is an effective way to remove impurities from chemicals including lithography chemicals. Among all, H-type strong acid cation resin (SA-IER) or materials with strong acid functional group show the relatively high metal removal performance due to its strong acidity. However, such strong acidity often causes hydrolysis of ester. For instance, hydrolysis reaction between propylene glycol monomethyl ether acetate (PGMEA) and strong acid functional group produces propylene glycol monomethyl ether (PGME) and acetic acid. On the other hand, H-type chelating resin (C-IER) can remove metal impurities to ppt level without causing hydrolysis. One issue was the Cr removal which was lower than other metals. As a solution, we optimized the mixed ratio of H-type C-IER and H-type SA-IER to increase the Cr removal performance without causing hydrolysis. The optimized volume of SA-IER in the mixture was 20 to 33 %. Another issue was the conditioning of ion exchange resin to remove water content from the resins and replace to target chemicals, particularly the solvents. Our new eco-friendly method for conditioning using MeOH significantly reduced the total amount of solvent needed for conditioning of ion exchange resins.
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