• Korean Journal of Materials Research
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• v.17 no.8
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• pp.402-407
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• 2007

In electronics manufacturing processes, soldering process has generally been used in surface mounting technology. Because of environmental restriction, lead free solders as like a SnAgCu ternary system are being used widely. After soldering process, the formation and growth of intermetalic compounds(IMCs) are formed in the interface between solder and Cu substrate as follows isothermal temperature and time. In this studies, therefore, we investigated the effects of the Cu substrate thickness on the IMC formation and growth of Sn-40Pb/Cu and Sn-3.0Ag-0.5Cu/Cu solder joints, respectively. The effect of the Cu thickness in PCB Cu pad and pure Cu plate was analyzed as measuring of thickness of each IMC. After solder was soldered on PCB and Cu plate which have different Cu thickness, we measured the IMC thickness in solder joints respectively. Also we compared with the effectiveness of Cu thickness on the IMC growth. From these results, we calculated the activation energy.

• Journal of the Korean Ceramic Society
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• v.38 no.7
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• pp.628-633
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• 2001

전자 패키징에 적용 가능한 저융점 유리 중에서 납성분이 포함되어 있지 않는 Bi계 유리의 연구를 행하였다. 기판과의 일체화를 위한 유리의 응용으로, 소자와의 반응 억제와 열응력 완화를 위해 유리의 저융점화 및 열팽창계수를 제어하였다. 본 연구에서 제조된 Bi계 유리는 DTA와 TMA의 열분석을 통해 5$50^{\circ}C$ 부근에서 연화점이 있고, 열팽창계수는 7.52~12.09$\times$$10^{-6}$/$^{\circ}C$의 범위였으며, 비유전율은 9~13이었다. 본 연구의 납성분을 포함되어 있지 않는 유리조성은 우수한 내산성을 나타내었다.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.74-74
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• 2009

카본나노튜브(CNT) 복합체는 우수한 기계적 성질을 가지고 있어 다양한 분야에서 연구되고 있다. 본 연구에서는 카본나노튜브(CNT)를 간단한 볼밀공정을 사용하여 Sn3.5Ag solder ball과 SAC305 powder 표면에 혼합하고 이를 통해 접합부 특성을 관찰하였다. 볼밀을 실시하기 전 카본나노튜브(CNT)는 초음파을 이용하여 분산을 실시하였다. Sn3.5Ag solder ball의 직경은 450um이고 SAC305 powder의 직경은 약 30um이었으며 이때 사용한 볼밀볼의 직경은 각각 3mm, 1mm이다. 볼밀 회전속도는 약 300rpm이고 6, 12, 18, 24시간동안 볼밀을 실시하였다. 24시간 볼밀 후에도 solder ball과 solder powder의 모양은 크게 변하지 않았다. SEM을 통해 표면을 관찰한 결과 분산된 카본나노튜브(CNT)는 solder ball과 solder powder의 표면에서 관찰되었다. 카본나노튜브(CNT)가 삽입된 solder ball은 BGA coupon 위에 놓고 Reflow를 실시하여 접합하였고 solder powder은 flux를 첨가하여 paste로 제조하여 2012 chip에 대한 접합특성을 관찰하였다. 카본나노튜브(CNT)는 solder ball 내부의 표면근처에서 관찰되었으며 카본나노튜브(CNT)가 혼합된 solder ball은 Aging 실시 후에 IMC 두께가 카본나노튜브(CNT)가 혼합되지 않은 solder ball에 비해 두께가 작고 접합강도는 약 10% 증가하였다. 또한 카본나노튜브(CNT)가 혼합된 solder paste와 카본나노튜브(CNT)가 혼합되지 않은 solder paste를 비교한 결과 인쇄성은 모두 양호하였으며 카본나노튜브(CNT)가 혼합된 paste를 사용한 chip의 전단강도가 높게 나타났다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.1
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• pp.6-12
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• 2019

Bonding properties of epoxy-containing solder joints were investigated by a high temperature aging test. Specimens were prepared by bonding an R3216 standard chip resistor to an OSP-finished PCB by a reflow process with two basic types of solder (SAC305 & Sn58Bi) pastes and two epoxy-solder (SAC305+epoxy & Sn58Bi+epoxy) pastes. In all epoxy solder joints, an epoxy fillet was formed in the hardened epoxy, lying around the outer edge of the solder joint, between the chip and the Cu pad. In order to analyze the bonding characteristics of solder joints at high temperatures, a high-temperature aging test at $150^{\circ}C$ was carried out for 14 days (336 h). After aging, the intermetallic compound $Cu_6Sn_5$ was found to have formed in the solder joint on the Cu pad, and the shear stress on the conventional solder joint was reduced by a significant amount. The reason that the shear force did not decrease much, even though in epoxy solder, was thatbecause epoxy hardened at the outer edge of the supported solder joints. Using epoxy solder, strong bonding behavior can be ensured due to this resistance to shear force, even in metallurgical changes such as those where intermetallic compounds form at solder joints.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.09a
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• pp.147-163
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• 2003

European Union bans the usage of Pb in electronics from July 1 st, 2006. The Near-eutectic Sn-Ag-Cu alloys are the leading candidate Pb-free solders (for SMT card assembly). .The microstructure of Sn-Ag-Cu alloys is discussed in terms of solidification, composition and cooling rate. Methods of controlling Ag3Sn plates are discussed. .Thermo-mechanical fatigue behaviors of Sn-Ag-Cu solder joints are reviewed. Tin pest, whisker growth, electromigration of Pb-free solders are discussed.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.4
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• pp.87-92
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• 2008

The interface microstructure of Sn-3.5Ag/Cu joint was modified by electroplating varying amount of Zn on Cu UBM. As the amount of Zn dissolved in Sn-3.5Ag solder increased with the electroplating Zn thickness, Cu-Sn IMCs such as $Cu_6Sn_5$ and $Cu_3Sn$ were replaced by Zn-containing IMCs such as $Cu_5Zn_8$ and $Ag_5Zn_8$, which increased the drop reliability of solder joints significantly. When the amount of Zn dissolved in solder was about 3.8wt%, drop resistance was best due to the effective suppression of Cu-Sn IMC and voids at the interface.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.4
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• pp.525-530
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• 2006

Recently companies which do not use the heavy metals such as lead, chrome, mercury to the electronic goods and alternate the materials environment-friendly are increasing. In advanced country, lead-free solder without lead is developed and soldering process almost disappeared. The lead-free solder is environment-friendly but is expensive and lack of tack and durability than lead, the improvement is necessary. To solve this problem, the welding process that uses TIG welding and the welding technology between different kind metals for lead-in wire of room lamp and base department was developed. To do this, previous room lamp manufacturing process was analysed and which process can be alternate was proposed. And the test for selection of optimal value of TIG welding parameter was done. Finally the lamp aging test and earthquake resistant test was done to check the reliability of welded room lamp.

• Journal of Welding and Joining
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• v.25 no.2
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• pp.37-42
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• 2007

• Proceedings of the KWS Conference
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• 2000.04a
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• pp.170-173
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• 2000

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.71-72
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• 2004

솔더접합부의 신뢰성을 평가하기위해서는 접합부에 대한 기본적인 기계적 특성 평가 및 온도, 수분, 진동, 응력 및 전압 둥 각종 환경하에서의 접합부에 대한 장단기 신뢰성시험이 요구된다. (중략)