Intermetallic Compound Formation in Sn-Co-Cu, Sn-Ag-Cu and Eutectic Sn-Cu Solder Joints on Electroless Ni(P) Immersion Au Surface Finish After Reflow Soldering
Journal article, 2006

The interfacial reactions between Sn-0.4Co-0.7Cu eutectic alloy and immersion Au/electroless Ni(P)/Cu substrate were investigated after reflow soldering at 260 °C for 2 min. Common Sn-4.0Ag-0.5Cu and eutectic Sn-0.7Cu solders were used as reference. Two types of intermetallic compounds (IMC) were found in the solder matrix of the Sn-0.4Co-0.7Cu alloy, namely coarser CoSn 2 and finer Cu 6 Sn 5 particles, while only one ternary (Cu, Ni) 6 Sn 5 interfacial compound was detected between the solder alloy and the electroless nickel and immersion gold (ENIG) coated substrate. The same trend was also observed for the Sn-Ag-Cu and Sn-Cu solder joints. Compared with the CoSn 2 particles found in the Sn-Co-Cu solder and the Ag 3 Sn particles found in the Sn-Ag-Cu solder, the Cu 6 Sn 5 particles found in both solder systems exhibited finer structure and more uniform distribution. It was noted that the thickness of the interfacial IMCs for the Sn-Co-Cu, Sn-Ag-Cu and Sn-Cu alloys was 3.5 μm, 4.3 μm and 4.1 μm, respectively, as a result of longer reflow time above the alloy's melting temperature since the Sn-Ag-Cu solder alloy has the lowest melting point. © 2006 Elsevier B.V. All rights reserved.


Peng Sun

Chalmers, Microtechnology and Nanoscience (MC2)

Cristina Andersson

Chalmers, Microtechnology and Nanoscience (MC2)

Xicheng Wei

Shanghai University

Zhaonian Cheng

Chalmers, Microtechnology and Nanoscience (MC2)

Dongkai Shangguan

Flextronics International

Johan Liu

Chalmers, Microtechnology and Nanoscience (MC2)

Materials Science & Engineering B: Solid-State Materials for Advanced Technology

0921-5107 (ISSN)

Vol. 135 2 134-140

Subject Categories

Electrical Engineering, Electronic Engineering, Information Engineering



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