Optimization of SMT solder joint quality by variation of material and reflow parameters

It is the objective of all PCB manufacturers to assure that each and every PCB supplied to the customer meets the specified quality requirements. Quality can be subdivided into two essential factors: the actual function of the PCB, and its reliability. Whereas function can, as a rule, be tested, only indirect substantiation is possible for reliability. The descriptions included in the IPC 610 D [1] standard are especially helpful in this respect, which indicate, amongst other things, which peculiarities the respective characteristics must demonstrate relative to product classes 1 through 3 in order to assure high reliability. At the same time, the number of repairs should be minimized to the greatest extent possible.