Process of reducing trace levels of metal impurities from resist components

摘要

A process of reducing trace metal impurities from an impure resist component solution comprising the steps of: (1) forming an impure resist component solution containing trace amounts of dissolved metallic impurities, the resist component solvent selected from the group consisting of ethyl lactate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, propylene glycol methyl ethyl acetate, or mixtures thereof; (2) contacting said impure resist component solution with a mixture of cyclohexane and isopropyl acetate and with an aqueous acidic solution for a sufficient amount of time to form a first two-phase reaction mixture comprising a first aqueous phase containing metallic impurities extracted from said impure resist component solution and a first organic phase containing said resist component solution with a reduced amount of trace metal impurities; (3) separating said first aqueous phase from said first organic phase; (4) contacting said first organic phase with a mixture of water and resist component solvent for a sufficient amount of time to form a second two-phase reaction mixture comprising a second aqueous phase containing metallic impurities extracted from said first organic phase and a second organic phase containing said resist component solution with further reduced amount of trace metal impurities; (5) separating said second aqueous phase from said second organic phase; and (6) removing said cyclohexane and said isopropyl acetate from said second organic phase, thereby forming a pure resist component solution.