Effect of the Variable Profile of Substrate Conductivity on the Dynamics of Metal Deposition on Resistive Disk

Abstract

A narrow profile of coating conductivity κd(r, t) formed at the initial stage ofmetal deposition, sharply increasing to the current feeder, notably improves current distribution over the resistive disk. However, with an increase in the average thickness of the coating and a decrease in the profile steepness, its leveling power gradually weakens until it reaches zero. All the factors that promote enhancement of the terminal effect (a decrease in the conductivity of the seed layer, an increase in disk radius) at the same time enhance the leveling role of the κd(r, t) profile. Under comparable conditions, the terminal effect on the resistive disk with external current feeder is exhibited much weaker than on resistive tape. This is connected with an increase in the cross section area, proportional to the radius, for current in the solid phase which is characteristic for disk. The transfer of the contact to the center of the disk into the zone with conductivity increasing from the current feeder causes a sharp enhancement of the terminal effect, in comparison with the resistive tape, too. © 2014 The Electrochemical Society.