• Journal of the Microelectronics and Packaging Society
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• v.27 no.3
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• pp.29-34
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• 2020

The behavior of brittle fracture of electroless nickel immersion gold (ENIG) /Sn-3.0wt.%Ag-0.5wt.%Cu (SAC305) solder joints was evaluated. The pH of the electroless nickel plating solution for ENIG surface treatment was changed from 4.0 to 5.5. As the pH of the Ni plating solution increased, pin hole in the Ni-P layer increased. The thickness of the interfacial intermetallic compound (IMC) of the solder joint increased with pH of Ni plating solution. The high speed shear strength of the SAC305 solder joint on ENIG surface finish decreased with the pH of the Ni plating solution. In addition, the brittle fracture rate of the solder joint was the highest when the pH of the Ni plating solution was 5.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.1
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• pp.86-91
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• 2007

Contact material is widely used as electrical parts. Ag-CdO has a good wear resistance and stable contact resistance. But the disadvantages of Ag-Cd alloy are coarse Cd oxides and harmful metal, Cd. Then Ag-Sn alloy that has stable and fine Sn oxide at high temperature has been developed. In order to investigate the effect of Te additional that affects the formation of the oxide layer on the surface and the formation of oxide in matrix Ag, we studied the microstructures and properties of Ag-Sn-In(-Te) material fabricated by rapid solidification process. The experimental procedure were melting using high frequency induction, melt spinning, and internal oxidation. Specimens were examined and analyzed by Transmission electron microscopy(TEM), energy dispersive X-ray spectroscopy(EDS) and Vickers hardness. As a result, internal oxidation was completed even at $600^{\circ}C$. Te forms coarse $In_{2}TeO_{6}$ phase and makes fine and well dispersed $SnO_{2}$ Phase. 0.3 wt% Te shows favorable properties.

• Proceedings of the KWS Conference
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• 2006.10a
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• pp.202-204
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• 2006

The reliability of insert mounted components has been considered as their life time was getting increased. The spread of crack and the growth of IMC(intermetallic compound) were observed by SEM(scanning electron microscope) and EDS(energy dispersive spectroscope). The cracks in Sn-37wt%Pb under thermal shock test were found earlier than other solders(Sn-3.0wt%Ag-0.5wt%Cu and Sn-0.7wt%Cu-0.01wt%P). The IMC thickness was increased with increasing number of thermal shock cycles in the following order : Sn-0.7Cu-0.01P; Sn-3.0Ag-0.5Cu; Sn-37Pb

• Proceedings of the KWS Conference
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• v.43
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• pp.31-32
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• 2004

• Journal of the Microelectronics and Packaging Society
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• v.30 no.1
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• pp.55-62
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• 2023

In this study, Sn-3.0Ag-0.5Cu (wt.%, SAC305) solder dipping process was performed between Ni-foam skeleton with different pore per inch (PPI) to fabricate Ni-foam/SAC305 composite solder, and then applied to the transient liquid phase (TLP) bonding process to evaluate the microstructure and mechanical properties of the bonded joint. The Ni-foam/SAC305 composite solder preform consisted of Ni-foam and SAC305, and an intermetallic compound (IMC) having a (Ni,Cu)₃Sn₄ composition was formed at the Ni-foam interface. During TLP bonding process, the IMC at the Ni-foam interface was converted to (Ni,Cu)₃Sn₄+Au, and as the bonding time increased, the Ni-foam and SAC305 continuously reacted, and the bonded joint was converted into an IMC. And it was confirmed that the 130 PPI Ni-foam/SAC305 composite solder joint was converted into an IMC at the fastest rate. As a result of performing a shear test to confirm the effect of Ni-foam on mechanical properties, solder joints under all conditions exhibited excellent mechanical properties of 50 MPa or more in the early stages of the TLP bonding process, and the shear strength tends to increase as the bonding time increases.

• Journal of Welding and Joining
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• v.35 no.3
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• pp.1-6
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• 2017

The effect of metal turnover (MTO) of electroless Ni plating bath on the brittle fracture behavior of electroless nickel electroless palladium immersion gold (ENEPIG)/Sn-3.0wt%Ag-0.5wt%Cu(SAC305) solder joint was evaluated in this study. The MTOs of the electroless Ni for the ENEPIG surface finish were 0 and 3. As the MTO increased, the interfacial IMC thickness increased. The brittle fracture behavior of the ENEPIG/SAC305 solder joint was evaluated with high speed shear (HSS) test. The HSS strength decreased with increasing the MTO of the electroless Ni bath. The brittle fracture increased with increasing the shear speed of the HSS test. The percentage of the brittle fracture for the 3 MTO sample was much higher than that for the 0 MTO sample.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.4
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• pp.61-68
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• 2023

In this study, Sn-3.5Ag-15.0Fe composite solder was manufactured and applied to TLP bonding to change the entire joint into a Sn-Fe IMC(intermetallic compound), thereby applying it as a high-temperature solder. The FeSn₂ IMC formed during the bonding process has a high melting point of 513℃, so it can be stably applied to power modules for power semiconductors where the temperature rises up to 280℃ during use. As a result of applying ENIG surface treatment to both the chip and substrate, a multi-layer IMC structure of Ni₃Sn₄/FeSn₂/Ni₃Sn₄ was formed at the joint. During the shear test, the fracture path showed that cracks developed at the Ni₃Sn₄/FeSn₂ interface and then propagated into FeSn₂. After 2hours of the TLP joining process, a shear strength of over 30 MPa was obtained, and in particular, there was no decrease in strength at all even in a shear test at 200℃. The results of this study can be expected to lead to materials and processes that can be applied to power modules for electric vehicles, which are being actively researched recently.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.333-337
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• 2008

This study investigates crack propagation behavior of Sn-3.0Ag-0.5Cu solder under pull-push loading conditions. Fatigue Crack Growth (FCG) tests were conducted on Center Cracked Plate (CCP) specimens in fast-fast (pp) strain waveform. The fast-slow (pc), slow-fast (cp) and slow-slow (cc) strain waveforms were also used to study the effect of strain rates. The crack propagation rates for the four strain waveforms were correlated with J-integral range and a scatter band of factor 4 was found. The crack growth rates for the pc waveform was highest, followed by cp, cc and then pp waveforms.

• Journal of the Korean institute of surface engineering
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• v.35 no.1
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• pp.47-52
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• 2002

Intermetallic compound on the soldered interface plays important role on the bondability and mechanical properties of soldered joint. The formation of intermetallic compounds are influenced by many factors such as temperature, holding time, base metals and so on. On this study the effect of number of reflow times on the intermetallic growth was investigated. For the experimental materials, Sn-3.5Ag-0.7Cu solder ball of 0.3mm diameter and RMA-type flux were used. Thickness of intermetallic compound of solder ball by 2nd reflow showed nearly 60% higher than that of 1st reflow, and shear strength showed 10% higher value. Thickness and shear strength according to the position of interface such as upper side or lower side between two substrates were also investigated.

• Proceedings of the KWS Conference
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• 2003.11a
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• pp.86-88
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• 2003

The characteristic of induction heating solder bump(solder ball: Sn-37Pb, Sn-3.5Ag, Sn-3.0Ag-0.5Cu) has analyzed in this paper. The initial condition of induction heating depends on the time and current. The shape of lead-free solder bump is better than lead solder. The shear strength of lead solder bump has decreased with aging time. The average of shear strength of solder bump is about 10N, 11N, and 11N respectively. The lead-free solder bump's shear strength is better than lead solder and varies irregularly with aging time.