Effect of Current Density and Electrolyte Concentration on Hillock Growth from Pure Sn Electrodeposits
Kil-Won Moon, S. -. Kim, Maureen E. Williams, William J. Boettinger, Gery R. Stafford
The effect of current density and Sn methane sulfonate concentration on hillock density, columnar grain size, crystallographic texture, and residual stress of bright Sn electrodeposits is measured. Correlation was found between hillock density and the ratio of the applied current density to transport limited current density. When the ratio exceeds unity no hillocks are observed. As the transport limited current is approached and exceeded, the columnar grain size decreases from 1.4 um to 0.7 um and the preferred orientation (fiber texture) rotates toward the  direction. Possible explanations are presented for how these factors reduce hillock growth. Because hillock and whisker growth are related phenomena, electrodeposition beyond the limiting current may be a possible whisker mitigation strategy.
Journal of Applied Electrochemistry
Sn whisker, Pb-free solder, electrodeposition, texture, preferred orientation, stress
, Kim, S.
, Williams, M.
, Boettinger, W.
and Stafford, G.
Effect of Current Density and Electrolyte Concentration on Hillock Growth from Pure Sn Electrodeposits, Journal of Applied Electrochemistry
(Accessed December 3, 2023)