Three-dimensional CAE of wire sweep and paddle shift in microchip encapsulation

In the packaging of plastic-encapsulated microelectronics (PEM), microchip encapsulation has been the dominant technique for encapsulation processes. During fabrication of microchip encapsulation, stress-induced problems such as wire sweep and paddle shift are the most common. The viscous drag force on wires exerted by the resin melt flow causes wire sweep problem, while non-uniform loading on paddle system applied by uneven melt flow within cavities results in paddle shift problem. With the tendency of encapsulation technologies continuously moving toward smaller scale and higher density, the existed defects problems during fabrication become more and more important. In this paper, an integrated CAE technology is developed to connect pre-process, filling and structure analyses and post-process, which gives a comprehensive solution for microchip encapsulation. By using this technology, wire sweep and paddle shift phenomenon inside the package can be examined easily. Furthermore, by comparing simulation results to experimental data, the prediction of wire sweep and paddle shift can be validated, which demonstrates the feasibility and usefulness of introducing CAE technology into mold design for microchip encapsulation.