Improvement of copper plating adhesion of PPE printed wiring board by plasma treatment

In this work we investigated the effects of plasma treatment on the surface of PPE printed wiring board (PWB) and on the adhesion of copper plating to that PWB. We used three kinds of processing gases: argon, oxygen, and a mixture of oxygen and carbon tetrafluoride for the plasma treatment. Plasma treatment was carried out for 10–180 s under a pressure 160 Pa, and a power of 1.5 kW. After the treatment, the surface morphology was observed by SEM in order to investigate the plasma etching, and the functional groups in the PPE surface were analyzed by XPS. The strength of the adhesion of the copper plating to the PPE PWB was measured by using a 90° peel tester. The peel strength of samples treated by any of the gases for 10 s reached a practical level, and the plasma treatment improved the adhesion of the copper plating adhesion without increasing the surface roughness of the PPE PWB.