This paper discusses the results of several independent experiments designed to address the many aspects of successful PoP integration. Assembly through the use of in-line stacking and pre-stacking was evaluated. Top package soldering was performed by dipping in either flux or paste. The warpage behavior of each level, as well as the full module was characterized through simulated reflow using Shadow-Moire analysis. Warpage behavior was found to be a limiting factor in assembly yields. Reliability of PoP assemblies was evaluated using drop/shock, vibration and thermal cycling. The level at which failure occurred depended on the location of the module on the PCB. Underfill was found to greatly enhance mechanical reliability, however thermal cycling reliability was decreased.
展开▼
