| 摘要 |
PROBLEM TO BE SOLVED: To make relatively easy concentration control of an etching solution of zinc oxide (ZnO). SOLUTION: As the etching solution of a zinc oxide film there is used one where isopropyl alcohol (IPA) is added to an aqueous phosphoric acid solution. In a two dot chain line in the figure (dopant ratio of isopropyl alcohol is 0%, i.e. as the etching solution there is used only an aqueous phosphoric acid solution), although phosphoric acid concentration must be about 0.056% in order to make a preferable etching rate about 100 nm/min, it is actually very difficult because accuracy beyond two places of decimals is required as concentration control of phosphoric acid. Against this, in a solid line in the figure (dopant ratio of isopropyl alcohol is 50%), provided the phosphoric acid concentration is about 0.056%, then the etching rate is about 30 nm/min; and, if the phosphoric acid concentration is about 0.187%, then the etching rate is about 100nm/min; so that it is possible to make this range a phosphoric acid concentration error allowable range. COPYRIGHT: (C)2006,JPO&NCIPI
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