The Formation of Whiskers on Electroplated Tin

Published

December 1, 2001

Author(s)

Kil-Won Moon, Maureen E. Williams, C E. Johnson, Gery R. Stafford, C A. Handwerker, William J. Boettinger

Abstract

ta is presented on the probability of whisker growth on as-grown tin (Sn) electrodeposits as a function of Cu concentration in the electrolye. A commercial bright methanesulfonate electrolyte was employed at 25 degreesC with copper (Cu) concentrations from 0 to 35 x 10(super-3) mole. To provide reproducible plating conditions and to approximate flow conditions in commercial strip plating, a rotating disk electrode assembly was used. Substrates for plating were pyrophosphate Cu and silicon (Si) single crystal (100) wafer coated with 40 nm of fine grain Cu by evaporation. The choice of Si(100) minimized externally applied deformation to the electrodeposits and provided single textured Cu(100). The composition of Cu in the Sn film increased depending on Cu concentration in the electrolyte. The effects of Cu on the deposit microstructures were finer grain size and a fibrous arrangement of Cu rich particles. For pyrophosphate Cu substrates, Cu in the Sn deposit caused Sn whisker growth after two days, and its frowth was exponentially proportional as a function of Cu content. However, Sn whiskers were not seen on the Cu coated Si(100) substrates during two months of observation. Thus, from the comparison of the prominent Sn whisker growth on the pyrophosphate Cu substrate to no whiskers on Cu coated Si(100) substrates, the effect of the preferred orientation the on Sn whisker growth was stronger than that of the grain size and shape.

Proceedings Title

Advanced Materials and Processing |4th |Pacific Rim International Conference | Japan Institute of Metals

Conference Dates

December 11-15, 2001

Conference Title

Pacific Rim International Conference On Advanced Materials and Processing

Pub Type

Conferences

Keywords

electroplated Sn, Pb-free solder, Sn whisker

Citation

Moon, K. , Williams, M. , Johnson, C. , Stafford, G. , Handwerker, C. and Boettinger, W. (2001), The Formation of Whiskers on Electroplated Tin, Advanced Materials and Processing |4th |Pacific Rim International Conference | Japan Institute of Metals (Accessed September 7, 2024)