Diffusion of Ag and Cu atoms in poly-ethylene-terephtalate (PET) and poly-imide (PI) was studied using Rutherford Backscattering Spectroscopy (RBS) and Elastic Recoil Detection Analysis (ERDA). The samples were prepared by deposition of Ag and Cu thin layers on polymer surface using CVD and diode sputtering techniques. Samples were annealed at temperatures up to 240°C. X-ray Photoelectron Spectroscopy (XPS) was used for determination of metal-polymer interaction and chemical state of atoms on metal- polymer interface. Faster diffusion of Ag atoms was observed from non-compact Ag layers prepared by diode sputtering than from those prepared by CVD technique. Ag atoms show higher mobility in PET in comparison with PI. XPS measurement gives an evidence of Ag clustering in Ag-PET samples prepared by cathode sputtering. In PI the Cu atoms exhibit higher diffusivity than Ag atoms due to their lower atomic radius.
  Metallization of polymers is essential for their application in microelectronic elements and photonics devices. We performed a study of the diffusion of Ag and Au atoms in polyethyleneterephtalate (PET). Thin metal layers were deposited using the diode-sputtering technique on polymer foils at room temperature. Simultaneous post-deposition annealing and plasma treatment was used to induce metal/polymer intermixing. Concentration profiles of diffused metals were determined by Rutherford backscattering spectrometry (RBS) and diffusion coefficients were extracted. The influence of the plasma treatment on the surface morphology was studied using atomic force microscopy (AFM). Ag atoms exhibit deeper penetration into polymer structures after Ar plasma treatment than after Ar + O2 plasma treatment. AFM measurements show more significant changes of surface roughness (increased roughness and porosity) of Ag on PET surfaces caused by the Ar + O2 plasma treatment compared to Au surfaces. In the case of very rough surfaces, a decrease of metal diffusivity is observed probably owing to a reduction of surface concentration. The metal mobility is strongly influenced by temperature, which is increased either by direct heating of the sample holder or indirectly by plasma discharge.