High-performance flip-chip BGA technology based on thin-core and coreless package substrate

A new organic build-up substrate packaging technology was developed in Fujitsu for high-end servers, where lower V-G impedance on substrate and thermal resistance are realized by applying metallic thermal injection materials. In the present paper, two important accomplishments in assembling process, eliminating voids with metallic thermal injection and controlling substrate flatness on mounting large LSIs, are investigated, and evaluated.