Boron and metal removal technology from PGMEA and NMP

Boron in organic solvent is one of the impurities which was difficult to remove by sub-boiling distillation as a result of our pre-evaluation. On the other hand, ion exchange reaction using Ion Exchange Resin (IER) treatment was effective to remove boron in comparison to the result of sub-boiling distillation. In this presentation, we evaluated the combination of three type of ion exchange resins; chelating (C-IER), strong acid (SA-IER), and strong base (SB-IER) to remove the metal impurities and boron from organic solvents. Propylene Glycol Monomethyl Ether Acetate (PGMEA) and N-Methyl-2-Pyrrolidone (NMP) were highlighted as target organic solvents. The target concentration level of each metal impurities was 1 ng/L. As a result, C-MB system consisted of two step treatment, C-IER followed by the mixture of SB-IER and SA-IER was effective for removing metal impurities from both PGMEA and NMP. In order to reduce the hydrolysis of PGMEA when contacting SB-IER, HCO₃ form SB-IER was adopted for the treatment.