• Proceedings of the Materials Research Society of Korea Conference
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• 1999.11a
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• pp.110-110
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• 1999

• Proceedings of the KWS Conference
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• 2002.05a
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• pp.263-265
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• 2002

• Proceedings of the KWS Conference
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• 2002.05a
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• pp.260-262
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• 2002

• Proceedings of the Materials Research Society of Korea Conference
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• 2000.11a
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• pp.164-164
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• 2000

• Proceedings of the Materials Research Society of Korea Conference
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• 1999.05a
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• pp.123-123
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• 1999

• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.72-72
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• 2005

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.5
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• pp.467-471
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• 2015

Thus far, solders used in electronics remain lead-based. Pb-free solutions in electronic components and systems are receiving increased attention in the semiconductor and electronics industries. Pb-free materials currently in used are Sn-37Pb, Sn-4Ag and Sn-4Ag-0.5Cu/Ni plate joints. In this study, solder alloys were used at high temperatures for artificial aging processing that was performed at $150^{\circ}C$ for 0hr, 100hr, 200hr, 400hr, 600hr and 1000hr. The SP test was conducted at $30^{\circ}C$ and $50^{\circ}C$. As a result, the maximum shear strength of all the specimens decreased with the increase in artificial aging time and temperature of the SP test. In addition, Pb-free solders showed higher total fracture energy compared with Sn-37Pb at high temperatures. The mechanical properties of Sn-4Ag-0.5Cu solder/Ni plate joints remained in excellent conditions in electronic parking systems at high temperatures.

• Transactions on Electrical and Electronic Materials
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• v.16 no.3
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• pp.112-116
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• 2015

This work studied the thickness and contact angle of solder joints between SAC 305 lead-free solder alloy and a Copper (Cu) substrate. Intermetallic compound (IMC) thickness and contact angle of 3Sn-Ag-0.5Cu (SAC 305) leadfree solder were measured using varying aging times, at a fixed temperature at 30℃. The thickness of IMC and contact angle depend on the aging time. IMC thickness increases as the aging increases. The contact angle gradually decreased from 39.49° to 27.59° as aging time increased from zero to 24 hours for big solder sample. Meanwhile, for small solder sample, the contact angle increased from 32.00° to 40.53° from zero to 24 hours. The IMC thickness sharply increased from 0.007 mm to 0.011 mm from zero to 24 hours aging time for big solder. In spite of that, for small solder the IMC thickness gradually increased from 0.009 mm to 0.017 mm. XRD analysis was used to confirm the intermetallic formation inside the sample. Cu₆Sn₅, Cu₃Sn, Ni₃Sn and Ni₃Sn₂ IMC layers were formed between the solder and the copper substrate. As the aging time increased, the strength of the solder joint mproved due to reduced contact angle.

• Korean Journal of Materials Research
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• v.24 no.3
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• pp.166-173
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• 2014

The effects of printed circuit board electroless nickel immersion gold (ENIG) and organic solderability preservative (OSP) surface finishes on the electromigration reliability and shear strength of Sn-3.5Ag Pb-free solder bump were systematically investigated. In-situ annealing tests were performed in a scanning electron microscope chamber at 130, 150, and $170^{\circ}C$ in order to investigate the growth kinetics of intermetallic compound (IMC). Electromigration lifetime and failure modes were investigated at $150^{\circ}C$ and $1.5{\times}10^5A/cm^2$, while ball shear tests and failure mode analysis were conducted under the high-speed conditions from 10 mm/s to 3000 mm/s. The activation energy of ENIG and OSP surface finishes during annealing were evaluated as 0.84 eV and 0.94 eV, respectively. The solder bumps with ENIG surface finish showed longer electromigration lifetime than OSP surface finish. Shear strengths between ENIG and OSP were similar, and the shear energies decreased with increasing shear speed. Failure analysis showed that electrical and mechanical reliabilities were very closely related to the interfacial IMC stabilities.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.3
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• pp.81-88
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• 2019

In this study, the effects of graphene oxide (GO) addition on electromigration (EM) lifetime of Sn-3.0Ag-0.5Cu Pb-free solder joint between a ball grid array (BGA) package and printed circuit board (PCB) were investigated. After as-bonded, $(Cu,Ni)_6Sn_5$ intermetallic compound (IMC) was formed at the interface of package side finished with electroplated Ni/Au, while $Cu_6Sn_5$ IMC was formed at the interface of OSP-treated PCB side. Mean time to failure of solder joint without GO solder joint under $130^{\circ}C$ with a current density of $1.0{\times}10^3A/cm^2$ was 189.9 hrs and that with GO was 367.1 hrs. EM open failure was occurred at the interface of PCB side with smaller pad diameter than that of package side due to Cu consumption by electrons flow. Meanwhile, we observed that the added GO was distributed at the interface between $Cu_6Sn_5$ IMC and solder. Therefore, we assumed that EM reliability of solder joint with GO was superior to that of without GO by suppressing the Cu diffusion at current crowding regions.