Localized recrystallization and cracking of lead-free solder interconnections under thermal cycling
| Autor: | Xuwen Liu, Maik Mueller, Hongtao Chen, Klaus-Juergen Wolter, Jue Li, Tonu Tuomas Mattila, Mervi Paulasto-Kröckel |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
polarized light microscopy
Materials science Mechanical Engineering recrystallization Metallurgy ta221 Recrystallization (metallurgy) orientation imaging microscopy Temperature cycling Nanoindentation Condensed Matter Physics Microstructure Mechanics of Materials electron back scatter difraction Soldering Ball grid array General Materials Science Grain boundary ta216 Electron backscatter diffraction solder interconnection |
| Zdroj: | JOURNAL OF MATERIALS RESEARCH. 26(16):2103-2116 |
| ISSN: | 0884-2914 |
| Popis: | The failure mechanism of lead-free solder interconnections of chip scale package–sized Ball Grid Array (BGA) component boards under thermal cycling was studied by employing cross-polarized light microscopy, scanning electronic microscopy, electron backscatter diffraction, and nanoindentation. It was determined that the critical solder interconnections were located underneath the chip corners, instead of the corner most interconnections of the package, and the highest strains and stresses were concentrated at the outer neck regions on the component side of the interconnections. Observations of the failure modes were in good agreement with the finite element results. The failure of the interconnections was associated with changes of microstructures by recrystallization in the strain concentration regions of the solder interconnections. Coarsening of intermetallic particles and the disappearance of the boundaries between the primary Sn cells were observed in both cases. The nanoindentation results showed lower hardness of the recrystallized grains compared with the non-recrystallized regions of the same interconnection. The results show that failure modes are dependent on the localized microstructural changes in the strain concentration regions of the interconnections and the crack paths follow the networks of grain boundaries produced by recrystallization. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink