A study of the insulator material for the interconnection in ALIVH/sup (R)/ substrate

Current demands in manufacturing of consumer electronics for smaller size, lighter weight and lower cost with high performance are most important. In order to meet these demands, high-density printed circuit boards (PCBs) are strongly required. Under this background, we have developed a new organic PCB called "ALIVH/sup (R)/" (any layer interstitial via hole). It realizes electric interconnections by interstitial via holes (IVHs) with cured conductive paste. Due to the ability to form the IVH in any layer and any position, the ALIVH substrate has an ideal IVH structure and is therefore excellent for high-density wiring. In the electric interconnections of ALIVH substrates, we found that it was the most important for the conductive paste to be compressed strongly in the laminating process. We examined one of the compression techniques, using nonwoven aramid paper as a reinforcing material. We studied the properties of nonwoven aramid-epoxy prepreg. As a result of our study, we found that the compression of the prepreg depended on the paper density and the resin content. Moreover, other PCB properties were also influenced by the paper density and the resin content. Therefore, the balance between the interconnection and the other properties is important to ALIVH substrates.