Improvement of adhesion properties for Cu films on the polyimide by plasma source ion implantation

Plasma source ion implantation (PSII) technique was used for the ion implantation and deposition of copper film on the polyimide. In PSII–EIAMAD (energetic ion assisted mixing and deposition) process, a polyimide film was immersed in a plasma, and high negative voltage pulses were applied to accelerate ions into the substrate resulting in the mixing effect of copper atoms with polyimide layers. This method was used to improve the adhesion between Cu layer and polyimide film depending on ion species, ion energy, and treatment time. The adhesion strength was determined by the 90° peel test. The deposited-copper surface was investigated by SEM and AFM, and the interface between Cu film and polyimide was characterized by AES. Enhancement of adhesion for PSII–EIAMAD treated copper film was observed and its interface was very gradient in AES depth profile. The Cu-deposited layers are adherent and reasonably stable after heat treatment of 24 h at 100 °C.