Abstract
In recent years, electronic devices have demanded higher density of interconnection and packaging, since many electronic equipments have become downsized and multifunctional. Generally, organic materials are used as the insulating element of Printed Circuit Boards (PCBs) and packaging components in electronic instruments. The formation of conductive layers for wiring on these insulators is a key technology. In particular, the formation of a metal conductive layer with excellent adhesion is demanded for the manufacturing of fine-pitch PCBs. In addition, the formation of smooth conductive layers will be required for fine-pitch PCBs in the near future. We studied the formation of conductive layers on smooth insulation resin without the need for roughening of the insulation resin surface by conventional oxidizing agents. Chemical modification on the insulation resin can be achieved by UV light irradiation in the presence of TiO2. Carbonyl groups are formed during the treatment. We confirmed that the modification of the insulation resin surface improves the adhesion between deposited copper and resin. Adhesion strength of 1.17 kgf/cm on plated copper films has been obtained, even on a smooth insulation resin surface, without roughening.
