Next generation ALIVH substrate for bare chip direct attach for mobile communications

The next generation ALIVH substrates named ALIVH -B and ALIVH -FB substrate were developed. These substrates are for the bare chip direct attach. The ALIVH-B substrate is suitable for less 400pins-count bare chip mounting and the ALIVH-FB substrate is suitable for more 400pins LSI. The design rule of the ALIVH-B substrate is Line/Space(L/S)=50/50 μm and Via hole diameter/Land diameter(V/L)=120/250 μm. For bare chip direct attach, we developed the following technologies, (1) The materials of the insulator and conductive paste in order to attain the package level reliability, (2) New CO 2 laser system for micro via hole drilling, (3) Fine pattern processing technology. We developed the ALIVH-FB substrate as much finer design rule substrate. The ALIVH-FB substrate has a structure that fine layers were formed on the surface of the conventional ALIVH-B substrate. The design rule of the fine layer is L/S=25/25 μm, V/L=50/150 μm. Three technologies were developed (1) Film insulator, (2) YAG THG laser drilling process, (3) Fabrication process of the fine layers by the transfer process. The ALIVH-B and ALIVH-FB substrate are very suitable for the bare chip direct attach technology by the fine design rule, via on via structure and outstanding properties of the insulator.