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Interfacial Reactions and Microstructures of Sn-0.7Cu- xZn Solders with Ni-P UBM During Thermal Aging.
- Source :
- Journal of Electronic Materials; Nov2009, Vol. 38 Issue 11, p2242-2250, 9p, 4 Black and White Photographs, 1 Diagram, 2 Charts, 5 Graphs
- Publication Year :
- 2009
-
Abstract
- The effects of the addition of Zn to Sn-0.7Cu solders are investigated. The study is focused on the interfacial reactions, microstructures, and mechanical properties after reaction with Ni-P under bump metallurgies (UBMs). The Zn contents in Sn-0.7Cu- xZn are varied as 0.2, 0.4, and 0.8 (in wt.% unless otherwise specified). In the reaction with Ni-P UBM during thermal aging at 150°C for 1000 h, (Cu,Ni)<subscript>6</subscript>Sn<subscript>5</subscript> intermetallic compounds (IMCs) are formed at the Sn-0.7Cu/UBM interface, whereas Zn is incorporated into IMCs to form (Cu,Ni,Zn)<subscript>6</subscript>Sn<subscript>5</subscript> in the Zn-doped solders. As the Zn content increases, the interfacial IMC thickness is reduced. A total reduction of about 40% in IMC thickness was observed for the 0.8% Zn-doped Sn-Cu. The same IMC particles are also observed in the matrix of each solder. In Sn-0.7Cu, (Cu,Ni)<subscript>6</subscript>Sn<subscript>5</subscript> particles are coarsened during aging, while (Cu,Ni,Zn)<subscript>6</subscript>Sn<subscript>5</subscript> particles in the Zn-added solders are less coarsened and remain much smaller than (Cu,Ni)<subscript>6</subscript>Sn<subscript>5</subscript>. The growth rate of (Cu,Ni)<subscript>6</subscript>Sn<subscript>5</subscript> during thermal aging is significantly suppressed by the addition of Zn. Consequently, after reaction with Ni-P UBM, the Zn-doped solders exhibit a thermally stable microstructure as measured by hardness and shear strength. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 03615235
- Volume :
- 38
- Issue :
- 11
- Database :
- Complementary Index
- Journal :
- Journal of Electronic Materials
- Publication Type :
- Academic Journal
- Accession number :
- 44513705
- Full Text :
- https://doi.org/10.1007/s11664-009-0867-3