Direct Observation of Nodule Growth on Electroless Ni-P Deposition in Supercritical CO2 Emulsion

Abstract

We have proposed a novel electroless plating using supercritical carbon dioxide emulsion (ELP-SCE) to obtain uniform and void-free Ni-P films. This reaction was conducted in emulsion of carbon dioxide (CO2) in Ni-P electroless plating solution with surfactant, and it showed an effect of nodules growth suppression. In this paper, we examine a direct observation of selected nodule growth in electroless plating reaction using atomic force microscope (AFM) on a square sample substrate of 50×50 μm fabricated by focused ion beam (FIB). The Ni-P film was plated by ELP-SCE again on the Ni-P plated film with nodule, which was formed by the conventional method. Changes in fine nodules and other areas at a specific position in the surface morphology were compared before and after the re-plating. In conventional method, nodules grew dominantly, while the growth was suppressed in ELP-SCE and the nucleation dominantly occurred in the surrounding regions of the nodules.