Influence of soldering condition on structure and reliability of solder joints made in Package-on-Package technology

As the miniaturization of the devices is progressing the chips have to have more functions and cover less space. One of the methods to achieve this goal is usage of Package-on-Package (PoP) technique. In this paper the influence of used soldering profiles on joints reliability will be presented. The boards had ENIG as final coating. The reliability was checked by the monitoring of resistance as the boards were tested in climatic chamber at -40°C to 105°C for 20 minutes at each chamber. IMC at the beginning of the test and after is presented.