Application of a Test Structure for Minimising Seed Layer Thickness of Electroplated Ferromagnetic Films

Abstract

This paper presents a previously documented full wafer test structure, designed to quantify the effect of seed layer thickness and conductivity on the plating uniformity of patterned electroplated structures. With magnetic films, non-magnetic seed layers need to be as thin as possible to minimise unwanted eddy currents. This paper uses the test structure to quantify the IR drop on the electroplated film and demonstrates how current distribution structures can be simply used to significantly improve wafer plating uniformity when using seed layer thicknesses of a few nanometers.