• 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.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.3
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• pp.64-72
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• 2023

In this study, after transferring graphene on a Cu substrate and printing a Sn-3.0Ag-0.5Cu Pb-free solder paste on the Cu substrate, effects of the transferred graphene on formations and growths of intermetallic compound (IMC) at the interface between the Cu substrate and the solder were reported during processes of reflow soldering and isothermal aging for 1000 h with various temperatures (125, 150, and 175 ℃). Thicknesses of Cu₆Sn₅ and Cu₃Sn IMCs at the interfaces with graphene were decreased during the reflow soldering and isothermal aging processes compared to those without graphene. The transferred graphene layers also showed that the growth rate constant and square of growth rate constant which related to the growth mechanisms of Cu₆Sn₅ and Cu₃Sn IMCs with t he t emperature a nd t ime of t he i sothermal aging c ould dramatically decreased.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.2
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• pp.91-97
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• 2014

With Pb-free solder joints containing Sn-Ag-Cu-based ternary alloys (Sn-1.0 wt.%Ag-0.5Cu and Sn-4.0Ag-0.5Cu) and Sn-Ag-Cu-In-based quaternary alloys (Sn-1.0Ag-0.5Cu-1.0In, Sn-1.2Ag-0.5Cu-0.4In, Sn-1.2Ag-0.5Cu-0.6In, and Sn-1.2Ag-0.7Cu-0.4In), fracture-mode change, shear strengths, and fracture energies were observed and measured under a high-speed shear test of 500 mm/s. The samples in each composition were prepared with as-reflowed ones or solid-aged ones at $125^{\circ}C$ to 500 h. As a result, it was observed that ductile or quasi-ductile fracture modes occurs in the most of Sn-Ag-Cu-In samples. The happening frequency of a quasi-ductile fracture mode showed that the Sn-Ag-Cu-In joints possessed ductile fracture properties more than that of Sn-3.0Ag-0.5Cu in the high-speed shear condition. Moreover, the Sn-Ag-Cu-In joints presented averagely fracture energies similar to those of Sn-Ag-Cu joints. While maximum values in the fracture energies were measured after the solid aging for 100 h, clear decreases in the fracture energies were observed after the solid aging for 500 h. This result indicated that reliability degradation of the Sn-Ag-Cu-In solder joints might accelerate from about that time.

• Proceedings of the KWS Conference
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• 1995.10a
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• pp.110-112
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• 1995

Initial solder joint strengths of various solder pastes, such as Sn-Pb(63-37wt%), Sn-In(52-48wt%), Sn-In-Ag(77.5-20-2.5wt%), and Sn-Ag(96.5-3.5wt%) has been studied. A system that can control the solder joint interface temperature during bonding process was also desined and implemented to improve solder joint integrity.

• Journal of the Korean Ceramic Society
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• v.48 no.1
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• pp.63-68
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• 2011

The investigation is directed to lead free (Pb-free) frits that can be used for organic light emitting diode, plasma display screen devices and other sealing materials. $P_2O_5$-SnO system glasses have been prepared for Pb-free low temperature glass frit. Structure and properties of the glasses with the composition SnO-$xB_2O_3-(60-x)P_2O_5$ (x=0, 5, 10, 15, 20, 25, 30, 35, 40 mol%) were characterized by infrared spectra (IR), X-ray diffraction(XRD), Density, Molar volume, Thermo mechanical analysis(TMA) and weight loss after immersion test. Glass transition temperature($T_g$), dilatometric softening temperature($T_d$) and chemical durability increased, and coefficient of thermal expansion($\alpha$) decrease with the substitution of $B_2O_3$ for $P_2O_5$ in the range of 0~25 mol%.

• Korean Journal of Materials Research
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• v.17 no.3
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• pp.152-159
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• 2007

When the electronics are tested with thermal shock for Pb-free solder joint reliability, there are temperature conditions with use environment but number of cycles for test don't clearly exist. To obtain the long term reliability data, electronic companies have spent the cost and times. Therefore this studies show the test method and number of thermal shock cycles for evaluating the solder joint reliability of electronic components and also research bonding strength variation with formation and growth of intermetallic compounds (IMC). SMD (surface mount device) 3216 chip resistor and 44 pin QFP (quad flat package) was utilized for experiments and each components were soldered with Sn-40Pb and Sn-3.0 Ag-0.5 Cu solder on the FR-4 PCB(printed circuit board) using by reflow soldering process. To reliability evaluation, thermal shock test was conducted between $-40^{\circ}C\;and\;+125^{\circ}C$ for 2,000 cycles, 10 minute dwell time, respectively. Also we analyzed the IMCs of solder joint using by SEM and EDX. To compare with bonding strength, resistor and QFP were tested shear strength and $45^{\circ}$ lead pull strength, respectively. From these results, optimized number of cycles was proposed with variation of bonding strength under thermal shock.

• Korean Journal of Food Science and Technology
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• v.7 no.1
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• pp.1-6
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• 1975

The changes of heavy metal amounts (Sn, Pb and Fe) in the Commercial white peach can between lacquered and plain can were investigated according to storage period which indicated as follows. 1. Lacquered and plain can, both of can got on increasing on all of heavy metal with expanding storage period. 2. Lacquered can showed that the heavy metal were on the decreased than plain can, while amounts of tin was considerably decreased. 3. Amounts of iron was proportionally increased with the increasing of detinning amounts. 4. Amounts of hazardous metal in all of the 6 commercial products were not reached at harmfull level of Korean food sanitation law.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.276-276
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• 2007

기존에 전자부품들에 사용되어 온 봉착용, 결합용, 코팅용 유리들은 타유리와 비교하여 낮은 융점을 가지고 있으면서도 열처리 전후에 물리, 화학적으로 매우 안정한 특성을 가지고 있는 PbO를 50~85% 이상 함유한 유리들이 대부분을 차지해왔다. 그러나 PbO 성분은 산성비 등의 산에 용해되어 Pb이온이 생성되면서 환경오염의 원인이 되기 때문에 유해성분으로 규정하고 있다. 최근 유해물질의 규제가 강화됨에 따라 PbO를 대체할 수 있는 $B_2O_3,\;Bi_2O_3,\;V_2O_5,\;P_2O_5$ 등의 새로운 조성의 유리에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 봉착용으로 사용되는 인산계 유리에서 RO계 첨가에 따른 TMA와 고온현미경, 필테스트를 통하여 접합성 및 열적특성 등의 변화에 대하여 조사하였다.

• Journal of the Microelectronics and Packaging Society
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• v.7 no.2
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• pp.63-68
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• 2000

This paper introduces the partial melting process for solder application and characterization of its possibility using off-eutectic Pb-Sn alloy. In order to show that the liquid phase in the semi-liquid state maintains the wettability as the single-phase liquid, the wetting balance test are conducted with varying temperatures and compositions. The results are then compared with the surface tension of liquid, both measured and calculated, to examine the correlation. The results from this investigation indicate that the partial melting can yield satisfactory solder joints as long as the liquid phase acquires sufficient chemical activity. At a condition where the partial melting is effective, a direct correlation between the wettability and the surface tension is found to exist. All alloys are found to show a reasonable wettability in semi-liquid state.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.140-143
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• 2001

A study has been made on the recovery of nitric acid and valuable metals such as Cu, Sn, Pb from the spent nitric etching solutions. The nitric acid was extracted effectively by TBP but the heavy metals such as Fe, Cu, Sn, Pb were not extracted by TBP from the spent nitric etching solutions. From the experimental results, 95% of nitric acid in spent etching solution was extracted at O:A ratio of 3:1 with five stage by 60% TBP and 98% of nitric acid was stripped from the loaded organic phase at O:A ratio of 1:1 with four stages by distilled water. After extracting nitric acid, Cu was recovered as a metal by electrowinning effectively and Sn was successfully removed by precipitation method by adjusting the pH of raffinate solution. Finally, Pb was recovered by cementation with iron scrap at $65^{\circ}C$. Parameters controlling the cementation process, such as temperature, pH and the effect of the additives were investigated.