Method for regenerating tetraalkylammonium hydroxide
US5405508A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 1994 |
| Grant date | Apr 11, 1995 |
| Priority date | — |
| Expiry date | Jul 29, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F2201/46115
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The present invention relates to a method for regenerating tetraalkylammonium hydroxide used as developer solution for positive type resist from waste developer solution. Waste solution from developer solution for positive type resist, which contains tetraalkylammonium hydroxide as principal component, is neutralized, and after depositing and removing alkali-soluble organic substances dissolved in it, it is electrolyzed in an anode chamber of an electrolytic cell partitioned by cation exchange membranes, and it is anodized in the anode chamber. Aqueous solution of tetraalkylammonium hydroxide obtained from the cathode chamber is further introduced to an anode chamber of the other electrolytic cell to perform multi-stage electrolysis or it is introduced into an anode chamber of an electrolytic cell partitioned into 3 chambers or more by two or more cation exchange membranes to perform multi-chamber electrolysis. The electrolytic solution of the intermediate chamber is circulated to an electrolytic cell for decomposing organic substances and electrolyzed, and tetraalkylammonium hydroxide, which can be re-used as developer solution, is obtained from the cathode chamber of the final st…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.