It is an accepted fact that copper-tin intermetallic formation is necessary to produce a solder wetted copper surface. It is also a fact that this same beneficial intermetallic formation could result in subsequent problems, such as brittle solder joints, tin depletion of solder and intermetallic cracking, if its formation is uncontrolled and excessive. Since its formation is a function of temperature, time, and the availability of reactants, these parameters must be controlled to some degree in order to minimise the chances of problem occurrence.