Abstract
Nano-sized, nonreacting, noncoarsening SrTiO3particles have been incorporated into Sn-3.0 wt% Ag-0.5 wt% Cu solder alloys and the interfacial microstructure and the shear strength on Au/Ni metallized Cu pads ball grid array substrates investigated as a function of the number of reflow cycles and aging time. At their interfaces, a scallop-shaped ternary Sn-Ni-Cu intermetallic compound layer was found in both plain Sn-Ag-Cu solder joints and solder joints containing SrTiO3nano-particles, and the intermetallic compound layer thickness increased with the number of reflow cycles and aging time. After the addition of SrTiO3nano-particles, in the solder ball region, a fine microstructure of AuSn4, Ag3Sn, Cu6Sn5intermetallic compounds appeared in the β-Sn matrix. In addition, the shear strength of solder joints containing SrTiO3nano-particles exhibited a consistently higher value than that of plain Sn-Ag-Cu solder joints due to a second phase dispersion strengthening mechanism as well as a refinement of the intermetallic compounds. The fracture surface of plain Sn-Ag-Cu solder joints exhibited a brittle fracture mode with a smooth surface while Sn-Ag-Cu solder joints containing SrTiO3nano-particles showed ductile failure characteristics with rough dimpled surfaces.
| Original language | English |
|---|---|
| Pages (from-to) | 1885-1892 |
| Number of pages | 8 |
| Journal | Journal of Alloys and Compounds |
| Volume | 509 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 3 Feb 2011 |
Keywords
- Ball grid array solder joints
- Microstructure
- Nano doping
- Shearing force
ASJC Scopus subject areas
- Mechanical Engineering
- Mechanics of Materials
- Materials Chemistry
- Metals and Alloys