A study on mechanical behaviour of lead-free solder using nanoindentation test
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Date
2018-05
Authors
Ong, Mei Kiem
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Abstract
As the usage of lead components has been limited by Europe Union, replacement
Sn-Ag-Cu is investigated and practiced in the electronic manufacturing field. Due to
constant push for miniaturization in the electronic package, the strength of solder joint of
the electronic component on circuit board is reduced due to the decrease in the contact area.
Therefore, enhanced mechanical properties of solder joint by embedding nanoparticles are
introduced to support changes in technology. The aim of the study is to investigate the
effect of nanoparticles reinforcement into nanocomposite solder on a) microstructure and
thickness of intermetallic compound layer b) hardness and elastic modulus of the
intermetallic compound layer and nanocomposite solder. In this study, 0.05wt% of TiO2,
Fe2O3 and NiO nanoparticle is mixed in solder paste respectively. By using surface
mounting technology, miniaturized capacitors are placed on printed solder paste on printed
circuit board before reflow soldering. Then, samples are prepared in cold mounted
sectioned printed circuit board. The mechanical characteristic is measured by using
nanoindentation experiment and observation on the sample surface is recorded. The
reinforcement of nanoparticles has caused the changes of morphology of IMC layer and
23% - 28% of thickness reduction of the IMC layer. The hardness and elastic modulus of
nanocomposite solder are increased by 1 % - 11% and 8% - 31% respectively. In the
conclusion, reinforcement of nanoparticles into composite solder has improved the
mechanical characteristic of nanocomposite solder and thus strengthen the solder joint.