Direct surface in-situ activation for electroless deposition of robust conductive copper patterns on polyimide film

Abstract

Abstract In this work, selective surface activation by means of an alkaline reagent and silver-ion catalyst precursor is proposed for fabricating adhesion-enhanced and fatigue-resistant copper patterns on polyimide (PI) film through electroless deposition (ELD). Results from peel strength measurements and cyclical bending tests demonstrate that the deposited copper patterns are holding significantly enhanced adhesion strength over PI substrate. Meanwhile, a low resistivity of 2.82 × 10−6 Ω cm, i.e. 1.6 times of the value for the bulk copper is obtained by this approach combined with related parameters optimization. Analyses based on morphological and elemental characterizations indicate that the excellent conductive and mechanical features of the copper patterns are resulted from elevated crystallinity and highly densified metallic grains.