SOFT GOLD PLATING LIQUID AND SEMICONDUCTOR DEVICE UTILIZING SOFT GOLD PLATING

摘要

PROBLEM TO BE SOLVED: To obtain a gold plating liquid which is free from environmental problems by the toxicity of cyanide and is excellent in safety and the quality of a gold plating film by adopting a non-cyanide-based gold plating liquid prepd. by using a conductive salt mixture composed of sulfite and thiosulfate of specific concns. as the soft gold plating liquid. ;SOLUTION: NaAuCl₄ as a metal salt is used in the plating liquid for gold plating used with a semiconductor device, etc. The conductive salt mixture composed of the sulfite, such as Na₂SO₂, as a first conductive salt and the thiosulfate, such as Na₂S₂O₃, as a second conductive salt is incorporated as the conductive salt in the gold plating liquid in such a manner that the total concn. thereof attains 0.8 to 2.8mol/l. In addition, the concns. of the first and second conductive salts with each other are kept within a rang of 40 to 250% and the concn. of at least either of the conductive salts is set at 0.4 to 1.4mol/l. The gold plating film having excellent wettability with solder and wire bondability is obtd. by using the gold plating liquid into which T1 ions are incorporated at 1 to 30ppm and which is adjusted in pH to 6 to 8 by a pH buffer.;COPYRIGHT: (C)1998,JPO