Improving predictability of wire-sweep in cavity filling analysis

Microchip encapsulation processes involves complex tooling and molding intricacies that affect moldability and quality yield in transfer molding process of packages. Wire sweep during molding is a major concern to mold engineers as the wire deformation behaviour during encapsulation is difficult to realise and control. Hence, analyzing the effects of polymer flow around circuit wires can help to identify bonding regions that are susceptible to significant wire deformations and check for potential wire shorting. Currently commercially available molding process simulation programs are widely used for transfer molding simulation to determine the wire deformation; However, some correlation discrepancy issues with actual measurements have been observed. Correlations are also inconsistent and the accuracy is specific to package design, cavity position and runner/gate configuration in the melt feed layout. This paper presents an evaluation study on three-dimensional (3D) moldfilling analysis on a demonstrator package with alternative simulation programs to check the influence of meshing methodologies and on the accuracy of wire-sweep predictions compared with measured wire-sweep data.