Effects of HDI material for laser via hole forming

Abstract

LVH (Laser Via Hole) forming is becoming the main current technology of micro-via forming in the process of build-up PWB. It was effected by the development of laser drilling technology. There are many kinds of HDI material for LVH forming: RCF (Resin Coated copper Foil), glass-epoxy, aramid, etc. The author studies the effective factors of HDI materials for LVH forming. The main conclusions are: the thermal decomposition temperature of HDI material is related to the bottom diameter of LVH; the reliability of LVH connection can be kept in any HDI materials, depending on good laser conditions for each material; and HDI material needs to be selected to meet the requirement for each product.