This work relates to the electroless nickel (EN) metallization and bumping processes for flip chip packaging applications. Zincating of the aluminum bond pads is an essential process step, activating the pads for EN deposition and ensuring good adhesion between the pad and the bump. Different zinc layer morphologies in terms of grain size or smoothness are reproducibly prepared by varying the zincating process parameters and chemical conditions. Quantitative correlations between the zinc layer morphology and the bump characteristics have been established.