Solderability of the Lead Free Surface Finishes

Paper deals with results of solderability testing. The importance of solderability testing grows up with implementing of lead free technology. Different properties of lead free solders, which replace SnPb solders, are first reason. Lead is also contained in surface finishes on component leads or printed circuit boards. Therefore the lead displacement in electronics assembly needs changes in surface finishes too. Lead has to be removed from surface layers of both component leads and printed circuit boards (PCB). In practice there are several types of lead free surface finishes. New surface finishes are second reason for solderability testing. This paper presents the comparison of individual lead-free possibilities. The solderability of several surface finish types was tested. Experiment was composed of resistor (1206) lead testing and of PCB coupon testing. The environment can affect the solderability of surface. That is why the solderability was measured before and after ageing. The results after aging were also presented