Surface Mount Assembly Problems Elimination of PC Solder Resist

The successful formation of solder joints to attach surface mount devices to multilayer printed circuit boards requires the electroplated, reflowed tin‐lead surface of the connection land to be completely free from contamination prior to the application of solder cream. Solder resists and their application methods are seen as the most common source of contaminant and the elimination of this process, at least on expensive buried logic multilayers, has been seen as the only long term solution. The technology described cannot be applied to double‐sided or four‐layer multilayers using surface mount and therefore the pursual of the ideal solder resist system cannot stop.