• Title/Summary/Keyword: solder joint reliability

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Lifetime Estimation of a Bluetooth Module using Accelerated Life Testing (가속수명시험을 이용한 블루투스 모듈의 수명 예측)

  • Son, Young-Kap;Chang, Seog-Weon;Kim, Jae-Jung
    • Journal of the Microelectronics and Packaging Society
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    • v.15 no.2
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    • pp.55-61
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    • 2008
  • This paper shows quantitative reliability evaluations of a Bluetooth module through extending previous qualitative methods limited to structure reliability tests and solder joint reliability tests for Bluetooth modules. Accelerated Life Testing (ALT) of the modules using temperature difference in temperature cycling as an accelerated stress was conducted for quantitative reliability evaluation under field environment conditions. Lifetime distribution parameters were estimated using the failure times obtained through the ALT, and then Coffin-Manson model was implemented. Results of the ALT showed that the failure mode of the modules was open and the failure mechanisms are both crack and delamination. The ALT reproduced the failure mode and mechanisms of failed Bluetooth modules collected from the field. Further, a quantitative reliability evaluation method with respect to various temperature differences in temperature cycling was proposed in this paper. $B_{10}$ lifetime of the module for the temperature difference $70^{\circ}C$ using the proposed method would be estimated as about 4 years.

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Studies on Copper Pillar Bump with Trapezoidal Cross Section on the Top Surface for Reliability Improvement (사다리꼴 상부 단면을 갖는 구리기둥 범프의 신뢰성 향상에 대한 연구)

  • Cho, Il-Hwan
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.7
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    • pp.496-499
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    • 2012
  • Modified structure of copper pillar bump which has trapezoidal cross section on the top region is suggested with simulation results and concept of fabrication process. Due to the large surface area of joint region between bump and solder in suggested structure, electro-migration effect can be reduced. Reduction of electro-migration is related with current density and joule heating in bump and investigated with finite element methods with variation of dimensional parameters. Mechanical characteristics are also investigated with comparing modified copper pillar bump and conventional copper pillar bump.

Evaluation of Property and Reliability of Sn3.5Ag and Sn0.7Cu Pb-free Solder Joint by Complex Vibration for Application of Automobile Electric Module (자동차 전장모듈대응을 위한 Sn3.5Ag와 Sn0.7Cu 솔더 접합부의 물리적 특성 및 복합진동을 통한 신뢰성 평가 - 자동차 전장모듈의 접합 신뢰성 연구 (II)-)

A Study on Optimal Design of Underfill for Flip Chip Package Assemblies (플립칩 어셈블리의 언더필 최적설계에 관한 연구)

  • Lee, Seon-Byeong;Kim, Jong-Min;Lee, Seong-Hyeok;Sin, Yeong-Ui
    • Proceedings of the KWS Conference
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    • 2007.11a
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    • pp.150-152
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    • 2007
  • It has been known that the underfilling technique is effective in reducing thermal and environmental stress concentration at solder joint in FC asscemblies. In this paper, the effect of thermomechanical properties of underfill such as coefficient of thermal expansion(CTE) and Young's modulus on reliability of FC assembly under thermal cycling was investigated. For parametric study for optimal design of underfill, finite element analyses(FEA) were performed for seven different CTEs and five different Young's modulus. The results show that the concentrated maximum stress decreases as Young's modulus of underfill increases and the CTE of underfill decreases.

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Laser Micro-Joining and Soldering (레이저 마이크로 접합 및 솔더링)

  • Hwang, Seung Jun;Kang, Hye Jun;Kim, Jeng O;Jung, Jae Pil
    • Journal of the Microelectronics and Packaging Society
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    • v.26 no.3
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    • pp.7-13
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    • 2019
  • In this paper, the principles, types and characteristics of the laser and laser soldering are introduced. Laser soldering methods for electronics, metals, semiconductors are also presented. Laser soldering is a non-contact process that transfers energy to solder joint by a precisely controlled beam. Demands for laser soldering are increasing due to bonding for complex circuits and local heating in micro joint. Laser absorption ratio depends on materials, and each material has different absorption or reflectivity of the laser beam, which requires fine adjustment of the laser beam. Laser types and operating conditions are also important factors for laser soldering performance. In this paper, the performance of Nd:YAG laser soldering is compared to the hot blast reflow. Meanwhile, a diode laser gives different wavelength and smaller parts with high performance, but it has various reliability issues such as heat loss, high power, and cooling technology. These issues need to be improved in the future, and further studies for laser micro-joining and soldering are required.

Evaluation of Mechanical Properties and FEM Analysis on Thin Foils of Copper (구리 박막의 기계적 물성 평가 및 유한요소 해석)

  • Kim Yun-Jae;An Joong-Hyok;Park Jun-Hyub;Kim Sang-Joo;Kim Young-Jin;Lee Young-Ze
    • Tribology and Lubricants
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    • v.21 no.2
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    • pp.71-76
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    • 2005
  • This paper compares of mechanical tensile properties of 6 kinds of copper foil. The beam lead made with copper foil. Different from other package type such as plastic package, Chip Size Package has a reliability problem in beam lead rather than solder joint in board level. A new tensile loading system was developed using voice-coil actuator. The new tensile loading system has a load cell with maximum capacity of 20 N and a non-contact position measuring system based on the principle of capacitance micrometry with 0.1nm resolution for displacement measurement. Strain was calculated from the measured displacement using FE analysis. The comparison of mechanical properties helps designer of package to choose copper for ensuring reliability of beam lead in early stage of semiconductor development.

Comparative Study of Interfacial Reaction and Drop Reliability of the Sn-3.0Ag-0.5Cu Solder Joints on Electroless Nickel Autocatalytic Gold (ENAG) (Electroless Nickel Autocatalytic Gold (ENAG) 표면처리와 Sn-Ag-Cu솔더 간 접합부의 계면반응 및 취성파괴 신뢰성 비교 연구)

  • Jun, So-Yeon;Kwon, Sang-Hyun;Lee, Tae-Young;Han, Deog-Gon;Kim, Min-Su;Bang, Jung-Hwan;Yoo, Sehoon
    • Journal of the Microelectronics and Packaging Society
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    • v.29 no.3
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    • pp.63-71
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    • 2022
  • In this study, the interfacial reaction and drop impact reliability of Sn-Ag-Cu (SAC) solder and electroless nickel autocatalytic gold (ENAG) were studied. In addition, the solder joint properties with the ENAG surface finish was compared with electroless nickel immersion gold (ENIG) and electroless nickel electroless palladium immersion gold (ENEPIG). The IMC thickness of SAC/ENAG and SAC/ENEPIG were 1.15 and 1.12 ㎛, respectively, which were similar each other. The IMC thickness of the SAC/ENIG was 2.99 ㎛, which was about two times higher than that of SAC/ENAG. Moreover, it was found that the IMC thickness of the solder joint was affected by the metal turnover (MTO) condition of the electroless Ni(P) plating solution, and it was found that the IMC thickness increased when the MTO increased from 0 to 3. The shear strength of SAC/ENEPIG was the highest, followed by SAC/ENAG and SAC/ENIG. It was found that when the MTO increased, the shear strength was lowered. In terms of brittle fracture, SAC/ENEPIG was the lowest among the three joints, followed by SAC/ENAG and SAC/ENIG. Likewise, it was found that as MTO increased, brittle fracture increased. In the drop impact test, it was confirmed that the 0 MTO condition had a higher average number of failures than the 3 MTO condition, and the average number of failures was also higher in the order of SAC/ENEIG, SAC/ENAG, and SAC/ENIG. As a result of observing the fracture surface after the drop impact, it was found that the fracture was between the IMC and the Ni(P) layer.

A Study on Growth of Intermetallic Compounds Layer of Photovoltaic Module Interconnected by Multi-wires under Damp-heat Conditions (고온고습시험에 의한 멀티 와이어 PV 모듈의 금속 간 화합물 층의 성장에 관한 연구)

  • Moon, Ji Yeon;Cho, Seong Hyeon;Son, Hyoung Jin;Jun, Da Yeong;Kim, Sung Hyun
    • Current Photovoltaic Research
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    • v.8 no.4
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    • pp.124-128
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    • 2020
  • Output power of photovoltaic (PV) modules installed outdoors decreases every year due to environmental conditions such as temperature, humidity, and ultraviolet irradiations. In order to promote the installation of PV modules, the reliability must be guaranteed. One of the important factors affecting reliability is intermetallic compounds (IMC) layer formed in ribbon solder joint. For this reason, various studies on soldering properties between the ribbon and cell have been performed to solve the reliability deterioration caused by excessive growth of the IMC layer. However, the IMC layer of the PV module interconnected by multi-wires has been studied less than using the ribbon. It is necessary to study soldering characteristics of the multi-wire module for improvement of its reliability. In this study, we analyzed the growth of IMC layer of the PV module with multi-wire and the degradation of output power through damp-heat test. The fabricated modules were exposed to damp-heat conditions (85 ºC and 85 % relative humidity) for 1000 hours and the output powers of the modules before and after the damp-heat test were measured. Then, the process of dissolving ethylene vinyl acetate (EVA) as an encapsulant of the modules was performed to observe the IMC layer. The growth of IMC layer was evaluated using OM and FE-SEM for cross-sectional analysis and EDS for elemental mapping. Based on these results, we investigated the correlation between the IMC layer and output power of modules.

High-Speed Shear Test Characterization of Sn-Ag-Cu-In Quaternary Solder Joint (Sn-Ag-Cu-In 4원계 무연솔더 조인트의 고속 전단 특성)

  • Kim, Ju-Hyung;Hyun, Chang-Yong
    • 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.

Properties of Cu Pillar Bump Joints during Isothermal Aging (등온 시효 처리에 따른 Cu Pillar Bump 접합부 특성)

  • Eun-Su Jang;Eun-Chae Noh;So-Jeong Na;Jeong-Won Yoon
    • Journal of the Microelectronics and Packaging Society
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    • v.31 no.1
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    • pp.35-42
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    • 2024
  • Recently, with the miniaturization and high integration of semiconductor chips, the bump bridge phenomenon caused by fine pitches is drawing attention as a problem. Accordingly, Cu pillar bump, which can minimize the bump bridge phenomenon, is widely applied in the semiconductor package industry for fine pitch applications. When exposed to a high-temperature environment, the thickness of the intermetallic compound (IMC) formed at the joint interface increases, and at the same time, Kirkendall void is formed and grown inside some IMC/Cu and IMC interfaces. Therefore, it is important to control the excessive growth of IMC and the formation and growth of Kirkendall voids because they weaken the mechanical reliability of the joints. Therefore, in this study, isothermal aging evaluation of Cu pillar bump joints with a CS (Cu+ Sn-1.8Ag Solder) structure was performed and the corresponding results was reported.