Adhesion properties of electroless-plated Cu layers on polyimide treated by inductively coupled Plasmas

This study investigated the improvements gained in the adhesion properties of electroless-plated Cu on a polyimide (PI) substrate by plasma surface treatments of PI using O-2 and N-2/H-2 inductively coupled plasma (ICP). The O-2 plasma treatment mainly induced physical changes which increased the surface roughness, whereas the N-2/H-2 plasma caused chemical changes to the PI surface via the creation of amine groups, thereby inducing effective adsorption of the Pd catalyst. The measured adhesion strength of the electroless-plated Cu to the PI surface was correlated with the plasma-induced, PI surface roughening. The present study results confirm the effectiveness of ICP surface treatments by O-2 followed by N-2/H-2 in increasing the adhesion strength of the electroless-plated Cu on the PI substrate.