In this study, the effect of sputtering power on the peel strength of the flexible copper clad laminate (FCCL) was evaluated before and after heat treatment using 180 degrees peel test. An increase in the sputtering powers from 200 W to 600 W increased film density and improved peel strength. To enhance peel strength much more, an inductively coupled plasma (ICP) was treated on the PI surface using N-2 gas with Ar as a function of RF power. A dramatic enhancement of the peel strength, 923 N/m was achieved, especially after heat treatment by changing ICP power from 200 W to 900 W. The reduction ratio of the peel strength for the 900 W plasma-treated FCCL was only 12%, whereas that for the 200 W plasma-treated FCCL was 43%. The root mean square (RMS) surface roughness with PIs exposed to both 200 W and 900 W plasma treatments was rarely changed, while X-ray photoelectron spectroscopy (XPS) showed the substantial increase of C-N functional groups. To obtain insight the film characteristics, the NiMoNb/PI interfaces were investigated by a high resolution transmission electron microscopy (HR-TEM). (C) 2015 Elsevier B.V. All rights reserved.