Method for manufacturing transfer film including seed layer, method for manufacturing circuit board by selectively etching seed layer, and etching solution composite

A method of manufacturing a circuit board by selectively etching a seed layer, the method comprising:

• a transfer-film preparing step of preparing a transfer film in which a seed layer of silver and a carrier member are stacked on each side of an insulating resin layer;
• a carrier-member removing step of stripping the carrier member from the transfer film to expose the seed layer;
• a circuit-pattern forming step of forming a circuit pattern of copper on the seed layer;
• and
• a seed-layer etching step of removing the seed layer exposed through the circuit pattern,
• wherein a thermosetting resin layer is interposed between the insulating resin layer and the seed layer of silver,
• wherein the thermosetting resin layer is applied as uncured onto the seed layer without being cured, and then cured in the bonding step of pressing and bonding the seed layer and the insulating resin layer in a thickness direction,
• wherein the seed-layer etching step comprises using a selective etching solution capable of dissolving only the seed layer of silver to selectively remove the seed layer,
• wherein the selective etching solution comprises an oxidizing agent;
• amines compound;
• an additive;
• and water,
• wherein the amines compound comprises one or more selected from a group consisting of ethylamine, propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, diethylamine, piperidine, tyramine, N-methyltyramine, pyrroline, pyrrolidine, imidazole, indole, pyrimidine, monoethanol amine, 6-amino-2-methyl-2-heptanol, 1-amino-2-propanol, methanolamine, dimethylethanolamine, N-methyldiethnaolamine, 1-aminoethanol, 2-amino-2-methyl-1-propanol.