Soldering method capable of providing a joint of reduced thermal resistance

摘要

A soldering method is disclosed as adapted for attaching semiconductor devices such as transistors to their lead mounts. A layer of a solder paste, premixed with rosin flux, is first printed or otherwise formed on each of a series of interconnected semiconductor mounts which may be in the form of a sheet metal punching. The semiconductor devices are placed on the respective solder layers. Then the solder layers are heated to a prescribed temperature higher than both the melting point of the solder and a flux activation temperature at which the flux starts bubbling within the solder. For thus heating the solder layers, the series of semiconductor mounts with the semiconductor devices placed thereon via the solder layers may be fed longitudinally over a suitably heated surface. Upon lapse of a preassigned length of time following the activation of the flux, a compressive is exerted on the successive solder layers, thereby driving of the gas bubbles generated by the flux for the provision of joints of reduced thermal resistance.