Characterization of additive systems for damascene Cu electroplating by the superfilling profile monitor

Gap-filling dynamics of several different species of additives for copper e lectrodeposition was investigated by monitoring the cross section of a part ially filled copper profile on the scanning electron microscopy photo. The filling ration Deltay/Deltax between "bottom-up" with "sidewall shift" was found to be proportional to the filing power of additives. The adsorption-d iffusion model combined with cathode polarization and cyclic voltammetric s tripping measurements was employed to explain the attribution of additives in superfilling phenomena. The superfilling dynamics was achieved under beh avior of additives providing selective inhibition gradient within the damas cene feature. By means of those analyses, we have optimized the appropriate amount of additives and achieved the superfilling performance for 0.15 mum vias with aspect ratio 6 by an acid-copper electrolyte with polyethylene g lycol, Cl-, and 2-mercaptopyridine (2-MP). Due to the additive of 2-MP, che late formed which enhanced adsorption ability on Cu-0 surface, and the conc entration gradient between side-wall shift and bottom-up in the damascene b ecame high enough to attend superfilling electroplating. (C) 2000 American Vacuum Society. [S0734-211X(00)13506-1].