To selectively etch a titanium-containing layer which is formed on a silicon substrate or a silicate glass substrate and mainly contains one or more substances selected from the group consisting of titanium, titanium oxides, titanium nitrides and titanium oxynitrides at a high etching rate without eroding the substrate.
The etching solution for etching a titanium-containing layer is formed on a silicon substrate or a silicate glass substrate and mainly contains one or more substances selected from the group consisting of titanium, titanium oxides, titanium nitrides and titanium oxynitrides. This etching solution contains silicofluoric acid. Also disclosed is a method for etching a titanium-containing layer formed on a silicon substrate or a silicate glass substrate using such an etching solution. The silicofluoric acid is a substance produced through a reaction between a hydrofluoric acid and silicon or a silicon oxide. While the silicofluoric acid is inactive against silicon or silicate glasses, it exhibits sufficient etching performance for titanium, titanium oxides, titanium nitrides and titanium oxynitrides. Consequently, the etching solution shows sufficient selectivity in etching of a titanium-containing layer formed on a silicon substrate or a silicate glass substrate.
KAWASE YASUHIRO
SAITO NORIYUKI
