Membranes for acid-sensitive solvents
This disclosure provides certain strong cation-modified ion exchange resins and membranes useful for carrying out the removal of metal and metal ion contaminants in fluid compositions. Filtered liquid compositions with significantly reduced amounts of metals can be used in a microelectronic manufacturing process, such as liquids for removing photoresist. The cation-modified ion exchange resins and membranes of the disclosure can be configured for use in a microelectronic manufacturing system, which can be utilized in the system as a point of use metal-removal feature for liquids entering the system. Advantageously, the filter materials and methods of this disclosure showed considerable improvement in preventing degradation and the formation of color bodies and dimeric and oligomeric materials from ketones (e.g., cyclohexanone) in the liquid compositions while not compromising the filter material's ability to remove undesired metal ions.
1 . A method of removing one or more metals or metal ions from a liquid composition, the method comprising:
(i) contacting a filter material with the liquid composition, wherein the liquid composition comprises at least one ketone and the one or more metals or metal ions, wherein the filter material comprises at least one strong acid functional group having a cationic counterion, wherein the strong acid functional group is selected from the group consisting of sulfonic acid, phosphonic acid, and combinations thereof, and wherein the cationic counterion is selected from the group consisting of ammonium, C1-C6 alkylammonium, cyclohexylammonium, phosphonium, C 1 -C 6 alkyl phosphonium, imidazolium, pyridinium, guanidinium, sulfonium, pyrrolidinium, morpholinium, and pyrimidinium; and
(ii) reducing an amount of the one or more metals or metal ions in the liquid composition to provide a purified liquid composition.
2 . The method of claim 1 , wherein the filter material comprises a membrane.
3 . The method of claim 1 , wherein the filter material is in the form of a resin bead.
4 . The method of claim 1 , wherein said purified liquid composition maintains a water white appearance for up to 7 days upon storage in an inert atmosphere.
5 . The method of claim 1 , wherein contacting the membrane with a liquid composition comprising at least one ketone for seven days leads to the liquid composition having an increase in the sum of dimeric and oligomeric condensation species in the liquid composition in a range from greater than 0% to less than 100% as compared to the sum of dimeric and oligomeric condensation species in the liquid composition before it is contacted with the membrane.
6 . The method of claim 1 , wherein the liquid composition comprises a ketone selected from the group consisting of cyclohexanone and methyl isobutyl ketone.
7 . The method of claim 1 , wherein the liquid composition further comprises one or more of n-butyl acetate, isopropyl alcohol, 2-ethoxyethyl acetate, xylene, ethyl lactate, isopentyl ether, methyl-2-hydroxyisobutyrate, methyl isobutyl carbinol, isoamyl acetate, undecane, propylene glycol methyl ether, propylene glycol monomethyl ether acetate, and a mixed solution of propylene glycol monomethyl ether (PGME) and PGMEA having a (7:3) mixing ratio and surface tension of 27.7 mN/m.
8 . The method of claim 7 , wherein the liquid composition comprises isopropyl alcohol.
9 . The method of claim 1 , wherein the one or more metal or metal ions are selected from the group consisting of Li, B, Na, Mg, Al, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Cd, Sn, Ba, and Pb metals or metal ions, and combinations thereof.
10 . The method of claim 1 , wherein the metal ions are selected from the group consisting of iron, chromium, manganese, aluminum, and nickel cations.
11 . The method of claim 1 , wherein the strong acid functional group is sulfonic acid and wherein the cationic counterion is ammonium.