Etching solution for multilayer film, etching concentrated solution, and etching method

摘要

When an etchant that alone can etch a multilayer film comprising a copper layer and a molybdenum layer is used during mass production, it is important for the cross-sectional shape of an edge after etching to satisfy the shape requirement of having a forward taper without an undercut, and that no precipitate be formed in the etchant. A multilayer-film etchant containing a copper layer and a molybdenum layer contains hydrogen peroxide, an inorganic acid, an acidic organic acid, a neutral organic acid, an amine compound, and a hydrogen peroxide decomposition inhibitor, but not an azole compound; therefore, no reaction products are generated from a reaction with the hydrogen peroxide, and no precipitates form in the etchant. Furthermore, the cross-sectional shape of the edge after etching can be formed into a desirable forward tapering shape. Containing no phosphorus compounds or fluorine compounds, the etchant will case minimal damage to the environment when disposed.