IMPROVED METAL-DIELECTRIC ADHESION FOR INTERCONNECT LINES OF MMICS AND ICS - AN EXPERIMENTAL-STUDY

Poor adhesion of the metal to the dielectric film may lead to loss of the device or circuit in the final stages of fabrication, for instance bonding. The present experimental study was carried out to improve me tal adhesion over polyimides and Si3Nx and SiOx grown by plasma-enhanc ed chemical vapour deposition. The metal lines were formed by depositi ng multilayer films by r.f. sputtering followed by electroplating of g old in some cases. The samples with poor metal-dielectric adhesion sho wed bubbling or blistering in the metal layer when subjected to temper ature cycles in the subsequent process steps. The experimental study p roved that in addition to the r.f. sputtering parameters and the preme tallization treatment, the thickness of the first metal layer in the m ultilayer metal scheme is critical to adhesion.