Radioengineering (Jun 2012)
Influence of Intermetallic Compounds on RF Resistance of Joints Soldered with Lead Free Alloys
Abstract
During soldering process intermetallic compounds as a reaction between solder and substrate are created. Physical properties of those compounds are different to properties of solder and substrate. The influence of intermetallic compounds (IMC) on radio frequency resistance of soldered joint has been identified. Tested solders were lead free Sn-1Cu, Sn-4Ag and Sn-3.8Ag-0.7Cu and lead containing Sn-37Pb (all in weight percent). Samples were annealed up to 3000 hours at 150 °C to accelerated growing of IMC. Radio frequency measuring method has been developed and is described. Influence of IMC on resistance of joint is growing with growing frequency because IMC with slightly different resistivity to base solder is creating barrier to current. Resistance of joints has been measured up to 3 GHz.
