Etchant and etching process for oxides containing at least indium and gallium

摘要

The present invention relates to an etchant and an etching process, which are preferred for use in etching of oxides containing at least indium and gallium, such as an oxide consisting of indium, gallium and oxygen or an oxide consisting of indium, gallium, zinc and oxygen. According to preferred embodiments of the present invention, an etchant comprising sulfuric acid or a salt thereof and a carboxylic acid (except for oxalic acid) or a salt thereof ensures a preferred etching rate, a good residue removal property and low corrosiveness to wiring materials when used in etching of oxides containing at least indium and gallium. Moreover, this etchant not only causes no precipitate but also retains a preferred etching rate even when the concentration of oxides dissolved in the etchant is elevated.

主权项

1. An etchant for etching an oxide containing at least indium and gallium, which comprises:
sulfuric acid or a salt of sulfuric acid; a carboxylic acid or a salt of the carboxylic acid; and a polysulfonic acid compound, wherein the carboxylic acid is not oxalic acid, and the polysulfonic acid compound is one or more members selected from the group consisting of a naphthalenesulfonic acid formalin condensate and a salt of the naphthalenesulfonic acid formalin condensate, a polyoxyethylene alkyl ether sulfate salt, and a polyoxyethylene alkylphenyl ether sulfate salt.