Abstract
Sn-3Ag-8Bi-5In solder (melting point, 461-477 K) was investigated as a lead(Pb)-free solder. In order to evaluate the solderability of the Sn-Ag-Bi-In alloy, the shear strength of soldered joint and inter-metallic compound (IMC) were investigated. As an experimental procedure, a 0.5 mm diameter solder was set on the Ni/Cu/Cr-pad of a Si-substrate. The solder ball on the pad was reflowed with Rosin Mildly Activated (RMA)-flux in air, and the reflow temperature was controlled between 483 K and 533 K. The shear strength and microstructure of the solder ball were evaluated with and without aging. The results show that the shear strength of the Sn-3Ag-8Bi-5In solder ball had the highest value of 1.69N by reflowing at 513 K for 10 s. The shear strength decreased from 1.69N to 0.95N as the IMC thickness was increased from 1.75 μm to 1.9 μm. Needle-shaped Ni3Sn4 and plate-like (Ni, Cu)3Sn4 formed on the interface between the solder and the Under Bump Metallization (UBM) that was bonded for 10 s at 513 K.
Original language | English |
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Pages (from-to) | 1791-1796 |
Number of pages | 6 |
Journal | Materials Transactions |
Volume | 43 |
Issue number | 8 |
DOIs | |
State | Published - Aug 2002 |
Keywords
- Inter-metallic compound
- Joint strength
- Microstructure
- Pb-free solder
- Sn-3Ag-8Bi-5In