| About this Abstract |
| Meeting |
2010 TMS Annual Meeting & Exhibition
|
| Symposium
|
Pb-Free Solders and Emerging Interconnect and Packaging Technologies
|
| Presentation Title |
A Quantitative Assessment of Microstructural Coarsening of SnAgCu Solders: Effect of Metallization and Thermo-mechanical History |
| Author(s) |
Praveen Kumar, Zhe Huang, Indranath Dutta, Ganesh Subbarayan, Vikas Gupta |
| On-Site Speaker (Planned) |
Praveen Kumar |
| Abstract Scope |
Microstructural coarsening in small Sn-3.8%Ag-0.7%Cu joints attached to Ni bond-pads and bulk solder samples, subjected to various thermo-mechanical histories, was quantitatively characterized. The Ag<SUB>3</SUB>Sn precipitates coarsened significantly faster in smaller joints as compared to the bulk samples, and the coarsening was more rapid nearer the bond-pads than farther away. This accelerated aging was attributed to the depletion of Cu from the joint samples due to solution/reaction with Ni pads. In addition to precipitate coarsening, the volume fraction of the eutectic-microconstituent also increased due to aging, leading to an accelerated increase in the inter-particle spacing. Based on these observations, we define a thermo-mechanical history dependent effective diffusion distance, on which precipitate spacing within the eutectic depends linearly. This proffers a single length parameter which may be used to describe in situ evolution of constitutive behavior due to precipitate coarsening during any thermo-mechanical history. |
| Proceedings Inclusion? |
Planned: Journal of Electronic Materials |