Patent Number: 8,299,303

Title: Process for producing a concentrated solution for a photoresist-stripping liquid having low water content

Abstract: There is provided a process for producing a concentrated solution of quaternary ammonium hydroxide which is characterized in that quaternary ammonium hydroxide in a form of water-containing crystals or of an aqueous solution is mixed with a water-soluble organic solvent selected from the group consisting of glycol ether, glycol and triol and the resulting mixed solution is subjected to a thin-film distillation in vacuo so as to evaporate the low boiling material. In accordance with this process, a concentrated solution of quaternary ammonium hydroxide having low water content is able to be easily produced.

Inventors: Hirose; Katsutoshi (Hyogo, JP), Koyama; Hiroya (Hyogo, JP), Kamasaka; Kimihiro (Hyogo, JP), Sasabe; Taro (Hyogo, JP), Kai; Naoshi (Hyogo, JP)

Assignee: KNC Laboratories Co., Ltd.

International Classification: C07C 211/62 (20060101); C07C 211/63 (20060101); C07C 209/82 (20060101)

Expiration Date: 2020-10-30 0:00:00