Rapid Deposition of Flexible Copper Clad Laminate Used Cu Film by Continuous High Power Magnetron Sputtering

Flexible copper clad laminates(FCCL)are fundamental materials in electronic information field,especially the polyimide/Copper(PI/Cu)double layered FCCL is extensively required because of its low dielectric loss with the development in high integration,high density and high working frequency.However,the fabricating methods have shortages in film density,adhesion and environmental friendly.This article aims to develop a completely vacuum method to fabricate the Cu film on flexible PI by Continuous high power magnetron sputtering(C-HPMS)which is reported to has both high deposition and high ionization rate.The film qualities are sequentially studied depending on power density,substrate temperature and bias.The results show that C-HPMS can produce a high Cu deposition rate of 1.72 μm/min and a dense Cu film with a diameter of 13.6~ 22.2 nm by extra substrate cooling.By the optimization of bias,a high adhesion of 0.76~0.87 N/mm between Cu film and the PI substrate is obtained.Compared with the rolled and electroplating copper films,the Cu film prepared by C-HPMS has obvious advantages in film density.Therefore,a lower electrical resistivity of 4.3×10^-8 Ωm can be achieved from a much thinner Cu film(2 μm)than the rolled and electroplating copper films(about 8 μm).