Abstract
Sn-9Zn with various additions of Sn-3.5Ag-0.5Cu powder was prepared by mechanically dispersing different weight percentages (1, 3, 5 and 7) of Sn-Ag-Cu powder into Sn-9Zn solder paste. In the Sn-Zn solder, scallop-shaped AuZn3intermetallic compound was found at the interfaces. On the other hand, in the Sn-3.5Ag-0.5Cu content solders, an additional ε-AgZn3intermetallic compound layer was found to be well adhered on the top surface of the AuZn3layer and the ε-AgZn3layer thickness increased with the number of reflow cycles. In addition, fine spherical-shaped ε-AgZn3intermetallic compound particles as well as an acicular-shaped Zn-rich phase was clearly observed in the β-Sn matrix. On increasing the Sn-Ag-Cu content, the shear load was increased from 1.80 to 2.03 kg after one reflow cycle. In the Sn-3.5Ag-0.5Cu content solders, the fracture surfaces exhibited typical ductile behavior with very rough dimpled surfaces while the fracture surface in the Sn-Zn solder gave fractures with a brittle appearance. In the fracture surface of the Sn-3.5Ag-0.5Cu content solders, some dimples were clearly observed associated with the formation of spherical-shaped ε-AgZn3intermetallic compound particles.
Original language | English |
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Pages (from-to) | 2347-2353 |
Number of pages | 7 |
Journal | Microelectronic Engineering |
Volume | 86 |
Issue number | 11 |
DOIs | |
Publication status | Published - 1 Nov 2009 |
Keywords
- Ball grid array solder joints
- Microstructure
- Shearing force
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics