Etching solution for etching multilayer thin film including copper layer and titanium layer, etching method using the same, and substrate obtained by using the etching method

摘要

The present invention relates to an etching liquid for etching a multilayer thin film comprising a copper layer substantially made of copper and a titanium layer substantially made of titanium, both of which are laminated on a substrate made using at least one selected among glass, silicon dioxide and silicon nitride. The etching liquid is an aqueous solution which contains: (A) from 4.5 to 7.5% by mass of hydrogen peroxide; (B) from 0.8 to 6% by mass of nitric acid; (C) from 0.2 to 0.5% by mass of a fluoride compound; (D) from 0.14 to 0.3% by mass of an azole; (E) from 0.4 to 10% by mass of an amine compound selected among (E1) an alkyl amine having at least one chain or branched alkyl group which has from 2 to 5 carbon atoms and can be substituted with a methoxy group, (E2) an alkanolamine having from one or two straight chain or branched hydroxyalkyl group having from 2 to 5 carbon atoms, and optionally having one or two straight chain or branched alkyl group having from 2 to 5 carbon atoms, (E3) a diamine having a straight chain or branched alkylene group having from 2 to 5 carbon atoms, and (E4) cyclohexylamine; and (F) from 0.005 to 0.1% by mass of a hydrogen peroxide stabilizer, and has a pH value of from 1.5 to 2.5.