PURIFICATION METHOD OF THINNER FOR RINSING PHOTORESIST

摘要

The present invention relates to a method for purifying a wasted thinner liquid for rinsing photoresist. More specifically, the method for purifying a wasted thinner liquid for rinsing photoresist comprises: a pretreating step including an alkali treating step of adding an alkali compound to a wasted thinner liquid including propylene glycol monomethyl ether acetate and alkyl lactate to dissolve the alkyl lactate; and a distilling step of distilling the wasted thinner liquid after the pretreating step, thereby effectively collecting a thinner component from the wasted thinner liquid.