| 摘要 |
PROBLEM TO BE SOLVED: To pattern or remove effectively a Bi-based oxide ceramic by a method wherein the Bi-based oxide ceramic is etched with etching chemicals consisting of a fluoride or a nitric acid. SOLUTION: Chemicals consisting of a fluoride in an acid medium is used in a wet etching. The wet etching chemicals contains an F solution in the acid medium consisting of a nitric acid. Various F sources are combined with an NHO3 and can be turned into a nitrate fluoride solution. Such F sources contain HF, and NH4F or NH4HF2, for example. The pH value of a nitrate fluoride etching liquid is lower than about 7 and preferably the pH value is about 5 or lower. Other pH values, such as the pH value of about 3 or lower, the pH value lower than about 0 and the pH value of about 1 or lower, are also preferable. When the acidity of an etching liquid rises, an etching rate is increased. Of cource, the pH value is optimized and a desired etching rate can be achieved for an individual process.
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