| 摘要 |
PROBLEM TO BE SOLVED: To improve the etching accuracy and enhance the safety by etching a halogen-containing cured epoxy resin while circulating and filtering an etching solution comprising an alkali metal compound, an amide solvent, and an alcohol solvent. SOLUTION: Etching is done while an etching solution comprising an alkali metal compound preferably in an amount of 0.5-40 wt.%, an amide solvent preferably in an amount of 50-99 wt.%, and an alcohol solvent preferably in an amount of 0.5-49.5 wt.% is being circulated through a channel having a filter pref. having an average porediametor of 0.5-100μm installed therein. The amide solvent is preferably N,N-dimethylformamide, N,N-dimethylacetamide, or N-methyl-2-pyrrolidone. The alcohol solvent is preferably methanol, ethanol, ethylene glycol (monomethyl or monoethyl ether), diethylene glycol (monomethyl ether), triethylene glycol, or the like. |
