Abstract
Abstract We developed the electrochemical displacement method of Cu seed-layer formed by replacing the amorphous-Si on Ta/SiO2/Si structure. The thickness of amorphous-Si varing from 200 Å ~ 400Å and HF concentration changing from 6% ~ 8% were performed in order to find the best condition for Cu seed layer deposition. The deposition rate, resistivity and depth profile of atomic composition for the displaced Cu seed layer were studied from measurement of SEM,α-step, Four Probe Point, Auger and SIMS. In addition, it was owing to TaOx resulting in poor adhesion when we discuss Cu films peeling by GIA XRD. After the rapid thermal annealing at temperature 400℃ for 400sec in N2 ambient, the resistivity of Cu seed layer is 28.6μΩ-cm. After electroplating Cu films, the grains texture, thermal stability and adhesion were detected by XRD, SIMS and 3-M scotch type test or adhesion testing. Subsequently, the thick a-Si layer protects Ta from oxidation, it does increase Cu/Ta adhesion, and RTA at temperature 400℃ for 400sec in N2 ambient will also improve ability of adhesion. Finally, the ability of filling vias with high aspect ratio was investigated. the seed layers can fill 0.11μm with aspect ratio 1.8 for a-Si 300Å and aspect ratio 2 for a-Si 400 Å.