The detailed characterization of polyimide (PI) surfaces modified by sequential O-2 and N-2/H-2 inductively coupled plasma (ICP) treatments was performed, and the effects of the surface morphological roughening and chemical modification of the PI surface on the adhesion properties of electroless-plated Cu on the PI systems were investigated. The increase in the surface morphological roughness induced by increasing the substrate bias power in the O-2 ICPs was primarily responsible for the enhancement of the adhesion strength of the electroless-plated Cu on PI. The amine (-NH2) or amide (-NH) functional groups generated on the PI surface, due to the opening of the cyclized imide ring by the subsequent N-2/H-2 plasma treatment, also enhanced the adhesion of the electroless Cu/PI interface. The peel tests confirmed the improvement of the adhesion strength, with the best peel strengths of congruent to 96 gf/mm being obtained for the sample subjected to the combined treatment of the sequential O-2 and N-2/H-2 ICPs. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3231849] All rights reserved.