• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2004년도 추계 기술심포지움 초록집
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• pp.49-49
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• 2004

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2003년도 추계학술발표대회 개요집
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• pp.80-82
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• 2003

• Transactions on Electrical and Electronic Materials
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• 제16권3호
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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.

• 한국전기전자재료학회논문지
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• 제23권8호
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• pp.611-616
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• 2010

This study investigated the characteristics of fracture behavior and mode on solder joints before and after thermal shock test for automotive application component using Sn-3.0Ag-0.5Cu solder, which has a outstanding property as lead-free solder. The shear strength was decreased with thermal cycle number, after 432 cycles of thermal shock test. In addition, fracture mode was verified to ductile, brittle fracture and base materials fracture such as different kind fractured mode using SEM and EDS. Before the thermal shock, the fractured mode was found to typical ductile fracture in solder layer. After thermal shock test, especially, Ag was found on fractured portion as roughest surface. Moreover, it occurred delamination between a PCB and a Cu land. Before thermal shock test, most of fractured mode in solder layer has dimples by ductile fracture. However, after thermal shock test, the fractured mode became a combination of ductile and brittle fracture, and it also could find that the fracture behavior varied including delamination between substrate and Cu land.

• 한국재료학회지
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• 제8권9호
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• pp.807-812
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• 1998

Sn-Bi-X(X:2Cu, 2Sb, 5In) 계 땜납과 Cu 기판과의 계면반응 및 기계적성질에 대하여 고찰하였다. Cu판과 땜납의 접합부는 $100^{\circ}C$에서 60일까지 열처리하여 광학현미경, SEM, EDS,분석을 통하여 시효처리에 따른 미세조직과 계면반응을 분석하였으며, 인장강도 및 연신율은 제조된 시편을 30일까지 열처리 한 후 0.3mm $\textrm{min}^{-1}$로 인장하여 시험하였다. 미세조직 분석결과 Cu의 첨가로 미세조직이 미세화 됨을 알 수 있으며, 계면에 형성된 화합물은 첨가원소에 따라 다르게 나타났다. 인장시험 결과 열처리 초기에는 땜납쪽에서의 파괴가 발생하였으나 열처리 시간이 증가하면서 계면반응층고 땜납의 계면에서 파괴가 발생하였다. 열처리에 따른 인장강도는 Cu를 첨가한 경우에 가장 높은 값을 나타냈다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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• pp.81-83
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• 2004

최근 대두되고 있는 환경오염문제로 인해 전자산업에서는 전 세계적으로 Pb 솔더에 관한 규제가 진행중에 있다. 이에 Pb free 솔더에 관한 연구가 활발히 진행 중에 있으며 그 중 Sn-Ag계 solder는 유력한 대체 solder로 대두되고 있다. (중략)

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.630-633
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• 2004

Generally, component and FR-4 board are connected by solder joint. Because material properties of components and FR-4 board are different, component and FR-4 board show different coefficients of thermal expansion (CTE) and thus strains in component and board are different when they are heated. That is, the differences in CTE of component and FR-4 board cause the dissimilarity in shear strain and BGA solder joint s failure. The first order Taylor series expansion of the limit state function incorporating with thermal fatigue models is used in order to estimate the failure probability of solder joints under heated condition. A model based on plastic-strain rate such as the Coffin-Manson Fatigue Model is utilized in this study. The effects of random variables such as frequency, maximum temperature, and temperature variations on the failure probability of the BGA solder joint are systematically investigated by using a failure probability model with the first order reliability method(FORM).

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2002년도 International Symposium
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• pp.203-215
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• 2002

Using eutectic In-Ag and Bi-Sn solder materials, we developed the COG technique having a minimum pitch of 50 ${\mu}{\textrm}{m}$. The maximum temperature in this process is $160^{\circ}C$. We fabricated spherical and uniform solder bumps by controlling the microstructure of Bi-Sn solder bumps. The contact resistances of Bi-Sn solder joints were 19 m$\Omega$ at $80{\mu}{\textrm}{m}$ pitch and 60 m$\Omega$ at $80{\mu}{\textrm}{m}$ pitch, respectively. These values are much lower than the contact resistance of the conventional ACF bonding. The contact resistances of the solder joint are almost the same before and after the underfill process. The contact resistance of the underfilled Bi-Sn solder joint did not change even after reliability test.

• Journal of Welding and Joining
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• 제14권3호
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• pp.86-92
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• 1996

This paper presents the investigations on the initial strength and its variation of Sn-Pb solder joint using different lead frames, such as are 42 alloy lead and Cu alloy lead. As the result of the lack of initial strength at solder joints, whose pitch is from 0.3 to 0.4mm, short circuit often occured at the solder joint by thermal shock or external impact. Therefore, in this paper investigations were performed on the initial strength and its variation of Sn-Pb solder joint as well as fractured mode with using different lead frames.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.978-983
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• 2014

This research proposes a method to estimate the fatigue life of solid-state drive(SSD) due to the effect of dummy solder ball under forced vibration. Mechanical jig is developed to describe the SSD in laptop computer. The jig with SSD is mounted on a shaker, and excited by a sinusoidal sweep vibration within the narrow frequency band around the first resonant frequency until the SSD fails. A finite element model of SSD is also developed to simulate the forced vibration. It shows that the solder joints at the corners of controller package are most vulnerable components and that placing dummy solder balls at those area is effective method to increase fatigue life of SSD.