Selective etching method

An etching method, comprising:

• bringing a layer of a metal selected from the group consisting of titanium, niobium, tungsten, molybdenum, ruthenium, rhodium, arsenic, aluminum and gallium, an oxide of the metal, a nitride of the metal, silicon nitride, hafnium nitride, tantalum nitride, and an alloy of these metals, said layer being provided on an underlying base material selected from the group consisting of glass, silicon, copper and nickel, into contact with an etching solution which consists essentially of at least one complexing agent selected from Formulas (I) and (II) and wherein the pH of said etching solution is 11 or higher, thereby selectively etching said metal;
• wherein R1 to R3 may be identical to or different from one another, and are selected from the group consisting of −Ra, —ORb, —OORe, —COORd, —COOORe, —CH2COORf, —CH2COOORg, —CRhO and —CH2CHCH3, where Ra to Rh may be identical to or different from one another, and are selected from the group consisting of hydrogen, a C1 to C10 saturated aliphatic group, a C1 to C10 unsaturated aliphatic group, and an aryl group, and
• wherein R4 to R7 may be identical to or different from one another, and are selected from the group consisting of —Ri, —ORj, —OORk, —COORl, —COOORm, —CH2COORn, —CH2COOORo, —CRpO, —CH2CHCH3, —CN, —NC, —NO2, —F, —Cl, —Br, —I, and —SO2Rq where Ri to Rq may be identical to or different from one another, and are selected from the group consisting of hydrogen, a C1 to C10 saturated aliphatic group, a C1 to C10 unsaturated aliphatic group, and an aryl group, and X is —OH, —COOH or —COOOH.