Differences between solder bonds made with SnPbAg and SnAgCu solders

Due to legislation and market trends, every electronic appliance assembler has to change leaded solders to lead free. In recent years, a number of manufacturers were simply waiting, and they know little or nothing about the behavior of lead free solders. However, there is now a necessity for lead free solders because the RoHS and WEEE directives are coming into effect by July 2006. To bring to light the particular differences between widely used industrial SnPbAg and SnAgCu solders, a test PCB for conventional SMT devices was designed and experimental soldering was done by IR reflow technology with both alloys.