Refinement recovery manner null of hydroxide tetra- alkylammonium from development

摘要

PROBLEM TO BE SOLVED: To industrially advantageously purify and recover a high-purity tetraalkylammonium hydroxide reusable in the photolithography process from a waste liquor containing a tetraalkylammonium hydroxide used as a positive- type resist developer. ;SOLUTION: A waste liquor containing a tetraalkylammonium hydroxide is treated with activated carbon to adsorb the impurities in the waste liquor to the activated carbon and remove them. Alternatively, the waste liquor is neutralized to remove the resultant insolubilized deposits, and then treated with activated carbon to adsorb the impurities in the waste liquor to the activated carbon and remove them; the resultant waste liquor is subjected to electrodialysis in an electrolytic bath using a cation exchange membrane.;COPYRIGHT: (C)1998,JPO