What's happening at Nihon Superior in 2008?

For Nihon Superior the greatest opportunities seem likely to be in the migration of their SN100C technology from the wave soldering process where its credibility was first established to reflow soldering and to flip chip and area array package attach. The opportunity to use SN100C� as a drop-in replacement for SAC305 in reflow soldering has been created by the use of thermal profiles with peaks in the range 245�-255�C despite the nominal 217�C melting point of the tin-silver-copper alloy. It has been found that because of its high fluidity close to its melting point SN100C�, with a melting point of 227�C can in most cases be successfully reflowed with the same profile in the multizone forced convection reflow ovens that are now commonly used. This fact combined with the reliability advantages described later is resulting in a great increase in interest in using SN100C� in reflow soldering.

Interest in the use of SN100C� in flip chip and area array package attach has resulted from problems encountered with the failure of portable devices when dropped. It has been realized that although SAC305 is strong it tends to be brittle, particular at the high strain rates experienced in shock loading. By contrast SN100C� is a softer alloy that retains its high ductility even at high strain rates.

That same combination of adequate strength with high ductility has also been found to result in SN100C� outperforming SAC305 in situations where the solder joint has to accommodate substantial strain, e.g. in vibration.

The development of improved core fluxes has created new opportunities for the use of SN100C� solder wire in robotic soldering

Another development that is creating an opportunity for a substantial growth in sales of the SN100C� technology has been the renewed interest in the hot air solder leveling (HASL) process as a printed circuit board finish. The electronics industry had largely accepted the argument of proponents of alternative lead-free PCB finishes such as immersion silver and OSP that there would be no place for the HASL process in the lead-free era so these were the finishes most widely used in the first stage of lead-free implementation. However as problems have emerged of creep corrosion with immersion silver and dry joints with OSP there has been renewed interest in the finish that served the industry so well during the era of tin-lead solder. The high fluidity of the SN100C�, its low tendency to erode copper and the stability of the nickel-containing interfacial intermetallic has made it the preferred alloy for the lead-free HASL process.