Abstract
A major manufacturing defect encountered in plastic encapsulation of IC components by transfer molding is wire sweep, the permanent deformation of wirebonds under the hydrodynamic loads imposed by the viscous flow front. Optimization of design geometries and processing conditions to minimize defects still cannot be achieved without time-consuming and expensive experiments that frequently involve hardware modifications. Thus, a need for simulation and defect-prediction techniques to replace the costly experiments is much needed for true design-for-manufacturability and faster cycle time.
This paper will present the results of a DARPA-funded program to develop a self-contained methodology and software suite (called PLICE-CAD) for modeling the entire packaging process. Simulation of the reactive flow in the molding of a thin quad flat package (TQFP) will be presented and validated with operating parameters (e.g., pressure, temperature, flow front advancement, ...) measured with in-process sensors.
