チオ尿素-ヒドロキノン2元還元剤系を用いた極めて安定な非シアン無電解金めっき浴 [in Japanese] A Very Stable Non-cyanide Electroless Gold Plating Bath Using Thiourea and Hydroquinone as a Cooperating Double Reductant System [in Japanese]
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The paper reports a new autocatalytic electroless gold plating bath that achieves almost neutral, low temperature bath conditions and excellent process stability without cyanide. The bath contains a thiosulfatesulfite mixed complex of Au (<b>I</b>) as the gold source and two reducing agents, thiourea and hydroquinone. The thiourea acts as the primary reductant for the gold complex, while the hydroquinone recycles thiourea by reducing the intermediate thiyl radical derived from thiourea oxidation. Therefore hydroquinone functions as a thiourea regenerator. This unique cooperative reductant system offers superb bath stability. The bath has been applied not only to the most advanced mainframe MLC boards but also to a variety of very fine pitch organic PWBs manufacturing process.
- Jitsumu Hyomen Gijutsu
Jitsumu Hyomen Gijutsu 49(12), 1298-1304, 1998-12-01
The Surface Finishing Society of Japan