Fine pattern formation（L/S＝less than 50 μm）using electroless nickel/gold plating, extraneous nickel deposition on the resin area of a fine pattern is often observed because of residual palladium catalyst on the patterns. Thinner nickel plating was applied to solve the problem. However, a tendency for local nickel corrosion caused by the immersion gold plating step increases. Also, the solder connection reliability decreases compared to conventional nickel/gold processing. Accordingly, this study investigated the influence of palladium catalyst deposition conditions on electroless nickel/gold plated film properties. We propose direct electroless nickel strike plating on copper patterns without the palladium catalyst. Generally, solder bonding strength with electroless thin nickel /gold plating decreased concomitantly with increased palladium catalyst treatment time. In contrast, the nickel strike plating time does not influence solder bonding strength. Uniform nickel deposition and good solder bonding strength were achieved by applying the electroless nickel strike plating method.
To produce bulk nanocrystalline Ni-Mo alloys with high plasticity, we developed Ni-Mo alloy electrodeposition processes showing high current efficiency and causing no micro-crack occurrence on electrodeposits. Electrodeposition was conducted using electrolytes consisting primarily of nickel sulfamate and sodium molybdate, with sodium gluconate. Using sodium gluconate and applying current density of 20-30 mA/cm2 improved the current efficiency to approximately 90%, efficiently producing a bulk 1mm thicksample. For Mo contents of 0.7-2.9 at%, the electrodeposited alloys have a nano-crystalline structure with 14-37 nm grain sizes, which are dependent on the Mo content. The Ni-2 at%Mo alloy with grain size of 16 nm exhibited high hardness of 5.2 GPa and tensile strength of 1.4 GPa. However, the electrodeposited bulk nanocrystalline Ni-Mo alloys showed fracture in the elastic region. Present results and discussion show that low deformability was related to the high microstrain values and high impurity contents of electrodeposited Ni-Mo alloys. This study, which developed a high efficiency Ni-Mo alloy electrodeposition system, is expected to direct future work in this field.
A PVD thick film forming technique has been developed to produce a channel-type microgroove exhibiting a lubricant retention effect. This technique uses hard Cr plating with a channel-type microgroove prepared by etching as a PVD film underlayer. Surface morphology of the hard Cr plating with a channel-type microgroove is inherited by the PVD film. This study clarified that this technique can form a channel-type microgroove that penetrates from the underlayer surface to the surface of a PVD thick film with thickness greater than 10 μm. In Scratch tests and Rockwell indentation tests, the CrN thick film with the channel-type microgroove showed a higher adhesion than the conventional CrN thick film. In Pin-on disks test under a liquid paraffin and MoS2 lubricant environment, the CrN thick film with the channel-type microgroove maintained a low friction coefficient without seizing in conditions where general CrN thick film seized to the pin. In Cupping tests, the CrN thick film with the channel-type microgroove showed a lower drawing force and a higher lubricant retention capability than the conventional CrN thick film.