Localized Ni deposition improved by saccharin sodium in the intermittent MAGE process

Localized Ni deposition improved by saccharin sodium (SS) in the intermittent microanode guided electroplating (intermittent MAGE) process has been investigated. This effect is more complicated than conventional planar electroplating. If there was an insignificant amount of SS in the bath (i.e. less than 1.0 mM), then the radius of the fabricated nodular columns would range from 37.5 to 42.5 νm cyclically along the axis and the surface would be covered with a homogeneous layer of 3-8 νm Ni particles. In the presence of an optimal amount of SS (i.e. around 1.0-3.0 mM), columns with uniform radius (around 42.5 νm) were fabricated and the surface was covered by a homogeneous layer of fine Ni particles (i.e. diameter 1 νm). With higher SS (4.0-6.0 mM in the bath), columns were constructed with uniform radius but the surface was covered by alternating zones of coarse and fine Ni particles. For SS beyond critical concentrations (8.0 mM at 4.0 V and 10.0 mM at 4.5 and 5.0 V), no microcolumn could be constructed and a universal planar Ni deposition on the substrate was formed instead. SS is an absorbent and it leads to cathodic polarization in the electroplating process. The influence of SS on the asymmetrical electric field distributed in the local area and formed by localized electrochemical deposition (LECD) has been studied by the use of the proposed model in this work and commercial finite element software.