Evaluation of substrate (Ni)-catalyzed electroless gold plating process

• Published in: Journal of the Electrochemical Society Vol. 147; no. 3; pp. 1059 - 1064
• Main Authors: OSAKA, T, MISATO, T, SATO, J, AKIYA, H, HOMMA, T, KATO, M, OKINAKA, Y, YOSHIOKA, O
• Format: Journal Article
• Language: English
• Published: Pennington, NJ Electrochemical Society 01.03.2000
• Subjects: Cross-disciplinary physics: materials science; rheology; Electrodeposition, electroplating; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Emission spectroscopy; Nickel borides; Pore structure; Electroless deposition; Transition elements Compounds; Composition effect; Experimental study; Nickel phosphides; Electrodeposition; SEM; Gold ions; Transition elements Ions; Catalyst activity; Depth profiles; Anodic polarization
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1.1393313

The substrate (Ni)-catalyzed electroless gold plating process invented by Iacovangelo and Zarnoch has been investigated for plating gold on electroless nickel substrates for application to bonding of electronic devices. The process was found to yield uniform and adherent gold films on Ni-B substrates, whereas on Ni-P substrates acceptable gold films were obtained only when the P content was low and a pretreatment procedure was introduced to prevent the formation of surface oxide or to remove it completely. Unlike the conventional galvanic displacement process, the substrate-catalyzed process does not attack the nickel substrates and yields gold films with a very low porosity. Compared with autocatalytic electroless gold plating baths, the substrate-catalyzed bath is inherently more stable, although the maximum gold thickness obtainable is naturally limited. Results of these evaluations are presented in detail.