Behaviors of QFN Packages on a Leadframe Strip

Abstract To lower the manufacturing cost of quad flat no-lead (QFN) packages, the number of QFN packages on a leadframe must be increased. However, the increased number of packages or changes to the layout of QFN packages on the leadframe can impact the mold compound flow behavior, which will, in turn, affect warpage, and the generation of voids inside the mold compound. In this paper, both simulation and experimental approaches were conducted to study the behaviors of QFN packages on a leadframe strip. For simulation, we will demonstrate and present an analysis methodology to account for the in-line processing parameters, especially the step of manufacturing and processing the mold compound material to form the QFN packages on a leadframe strip. The in-line manufacturing parameters, such as pressure, temperature, shrinkage, and processing timing, were all considered and modeled. A commercial finite element tool was used. For the experiment, we measured the warpages and the voids of QFN packages as a func...