| abstract |
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. |