| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for chemically removing a metal coating from an outer surface of a substrate without affecting its inner surface. SOLUTION: The treatment method comprises a step of depositing a thermally decomposable wax (20) having a melting point higher than 75°C onto an inner channel (18) to mask the inner surface of the substrate (10) and a step of treating the substrate (10) using an aqueous solution containing an acid of the formula: H<SB>X</SB>AF<SB>6</SB>(wherein A is silicon, germanium, titanium, zirconium, aluminum or gallium; and x is 1-6). The aqueous solution has a melting point lower than that of the wax (20) and substantially removes the metal coating from the outer surface of the substrate (10). The wax (20) does not react with the aqueous solution and prevents it from contacting the inner surface of the substrate (10). The substrate (10) is subsequently heated so that the wax (20) is thermally decomposed without producing any harmful byproduct. COPYRIGHT: (C)2007,JPO&INPIT
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