Recent progress in popcorn performance and cost reduction of QFP160 using Ni-Pd plated dambar less lead frames

Reliability performance and cost reduction are the two main issues at present in the semiconductor back end assembly industry. A major step in cost reduction could be the dambar-less molding process, which reduces the trimming and forming costs. Together with Ni-Pd plated lead frames, which eliminates the pretinning process, significant cost reduction could be achieved, but current molding technology does not allow flash and bleed-free dambar-less molding. In addition, the existing molding compounds suffer from a fatal drawback: limited reliability performance due to poor popcorn resistance, mostly induced by insufficient adhesion of the encapsulant to the Ni-Pd plated lead frame. Indeed, no high pin count devices using the Ni-Pd plating technology are available on the market. The use of Pre-Packed Processing (3P^R) technology and processes together with a recently developed high performance compound without mold-release agents but using special adhesion promoters has virtually eliminated these problems and successfully achieved dambar-less molded devices with JEDEC-level 1 popcorn resistance on Ni-Pd plated lead frames. These results are presented and discussed with emphasis on 3P^R technology and the newly developed molding compound