Molding challenges of LOC packages with large devices

This paper presents the manufacturing challenges that were met for plastic encapsulation of lead on chip (LOG) products with large device-to-package area ratios. A new methodology for optimizing product and process performance has been used to eliminate the injection problems which were encountered with these packages. The influence of pellet preheat time and clamping force on the voids and on the knit-lines has been clearly demonstrated in a screening study. The injection speeds have been optimized to completely eliminate the emergence of the defects in a subsequent focusing study.