Recent Problem of Gold Plating and Its Patent Search

Article covers gold plating from Japanese patent search, subjects of gold plating in package technology, and formation of fine pattern for metal nano particles. Recent patents relate to electroless gold plating (reduction type and replacement type gold plating) and electrolytic gold plating solutions. The subjects concern solder jointing, analysis of plating films, and other problems. An electroless gold plating solution consists of (g/L) sodium gold sulfite 2.5 (as gold), anhydrous sodium sulfite 32, sodium thiosulfate pentahydrate 26, sodium borate tetrahydrate 25, benzotriazole 2.5, and hydroquinol 5 as well as thallium nitrate (as Tl) 1 ppm and 2-mercapto-benzooxazole 1 ppm, with pH of 9 and solution temperature of 65 DGC. The solution provides a high plating speed up to 1.79 mum/h. This article deals with gold.