Ball Grid Array Package with the Copper Core Solder Balls.

Abstract

and temperature cyclic frequencies on the fatigue life of copper core solder joints in the PBGA package was studied. This paper describes copper core solder balls and the primary factors affecting solder joint reliability in the PBGA. 2. Solder Fatigue Cracking The reliability of devices operating in customer environment is a key concern in electronic packaging design2)•`15). One aspect of reliability that is of particular importance to PBGA packages is the potential early fatigue failures that can occur in the solder joints. These fatigue failures are induced by the thermal expansion mismatch between the silicon chip and the PCB, which creates cyclic loads on the solder joints from temperature excursions in the user environment. The accelerated thermal cycling test is a commonly used technique for evaluating the reliability of an electronic package. Fig.1 shows an example of failed copper core solder joint after a thermal cycling test for the PBGA package. Copper core solder joint cracking appeared at the interface between the copper trace and the solder material on the PCB side, and propagated almost 10) Masazumi Amagai:•gCharacterization of Molding Compounds and Die Attach Materials for Package Warpage and Solder Joint Reliability in Chip Scale Package (CSP)•h, Proceedings of American Society of Mechanical Engineers (ASME) InterPack '99 EEP-Vol.26-2, Advances in Electronic