• 제목/요약/키워드: solder joints

검색결과 239건 처리시간 0.021초

Pb-free 솔더 조인트의 인공시효 처리시간과 실험온도에 따른 강도평가 (Strength Evaluation of Pb-free Solder Joints with Artificial Aging Time and Test Temperature)

  • 박소영;양성모;유효선
    • 한국자동차공학회논문집
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    • 제22권3호
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    • pp.90-96
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    • 2014
  • The conventional SnPb solders were widely used for several decades in the electronic packing system due to the superior mechanical properties such as low melting point, better wettavility and good mechanical fatigue. However, in recent years, owing to adverse effect on the human health and environment, conventional SnPb solders have been replaced by Lead-free solders. In this research, the shear punch(SP) test of Sn-4Ag-(Cu)/Ni pad was performed. Pb-free solder alloys which are the environmentally friendly of the electronic components were performed at $150^{\circ}C$ for 100hr~1000hr to artificial aging processing. In order to evaluate the mechanical properties of solder joints, the SP test was conducted at $30^{\circ}C$ and $50^{\circ}C$. As a result, the maximum shear strength of almost the whole specimens was decreased with the increase in aging time and temperature of SP test. The mechanical properties of Sn-4Ag-0.5Cu solder were most excellent in all Pb-free solder which were produced by the SP test at $30^{\circ}C$.

하이브리드 신경회로망을 이용한 디지털 단층 영상의 BGA 검사 (Hybrid Neural Network Based BGA Solder Joint Inspection Using Digital Tomosynthesis)

  • 고국원;조형석;김종형;김형철
    • 제어로봇시스템학회논문지
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    • 제7권3호
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    • pp.246-254
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    • 2001
  • In this paper, we described an approach to the automation of visual inspection of BGA solder joint defects of surface mounted components on printed circuit board by using neural network. Inherently, the BGA solder joints are located underneath its own package body, and this induces a difficulty of taking good image of the solder joints by using conventional imaging systems. To acquire the cross-sectional image of BGA sol-der joint, X-ray cross-sectional imaging method such as laminography and digital tomosynthesis has been cur-rently utilized. However, the cross-sectional image obtained by using laminography or DT methods, has inher-ent blurring effect and artifact. This problem has been a major obstacle to extract suitable features for classifi-cation. To solve this problem, a neural network based classification method is proposed int his paper. The per-formance of the proposed approach is tested on numerous samples of printed circuit boards and compared with that of human inspector. Experimental results reveal that the method provides satisfactory perform-ance and practical usefulness in BGA solder joint inspection.

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Effect of under-bump-metallization structure on electromigration of Sn-Ag solder joints

  • Chen, Hsiao-Yun;Ku, Min-Feng;Chen, Chih
    • Advances in materials Research
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    • 제1권1호
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    • pp.83-92
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    • 2012
  • The effect of under-bump-metallization (UBM) on electromigration was investigated at temperatures ranging from $135^{\circ}C$ to $165^{\circ}C$. The UBM structures were examined: 5-${\mu}m$-Cu/3-${\mu}m$-Ni and $5{\mu}m$ Cu. Experimental results show that the solder joint with the Cu/Ni UBM has a longer electromigration lifetime than the solder joint with the Cu UBM. Three important parameters were analyzed to explain the difference in failure time, including maximum current density, hot-spot temperature, and electromigration activation energy. The simulation and experimental results illustrate that the addition 3-${\mu}m$-Ni layer is able to reduce the maximum current density and hot-spot temperature in solder, resulting in a longer electromigration lifetime. In addition, the Ni layer changes the electromigration failure mode. With the $5{\mu}m$ Cu UBM, dissolution of Cu layer and formation of $Cu_6Sn_5$ intermetallic compounds are responsible for the electromigration failure in the joint. Yet, the failure mode changes to void formation in the interface of $Ni_3Sn_4$ and the solder for the joint with the Cu/Ni UBM. The measured activation energy is 0.85 eV and 1.06 eV for the joint with the Cu/Ni and the Cu UBM, respectively.

전기도금법을 이용하여 형성한 Au-Sn 플립칩 접속부의 미세구조 및 접속저항 (Microstructure and Contact Resistance of the Au-Sn Flip-Chip Joints Processed by Electrodeposition)

  • 김성규;오태성
    • 마이크로전자및패키징학회지
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    • 제15권4호
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    • pp.9-15
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    • 2008
  • Au와 Sn을 순차적으로 도금한 Au/Sn 범프를 플립칩 본딩하여 Au-Sn 솔더 접속부를 형성 후, 미세구조와 접속저항을 분석하였다. $285^{\circ}C$에서 30초간 플립칩 본딩한 Au-Sn 솔더 접속부는 $Au_5Sn$+AuSn lamellar 구조로 이루어져 있으며, 이 시편을 $310^{\circ}C$에서 3분간 유지하여 2차 리플로우시 $Au_5Sn$+AuSn interlamellar spacing이 증가하였다. $285^{\circ}C$에서 30초간 플립칩 본딩한 Au-Sn 접속부는 15.6 $m{\Omega}$/bump의 평균 접속저항을 나타내었으며, 이 시편을 다시 $310^{\circ}C$에서 3분간 유지하여 2차 리플로우 한 Au-Sn 접속부는 15.0 $m{\Omega}$/bump의 평균 접속저항을 나타내었다.

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Sn-3.0wt.%Ag-0.5wt.%Cu 솔더 볼 접합부의 고속전단 특성 (Characteristics of the High Speed Shear Test for Sn-3.0wt.%Ag-0.5wt.%Cu Solder Ball Joints)

  • 이영곤;이희열;문정탁;박재현;한신식;정재필
    • 대한금속재료학회지
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    • 제47권9호
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    • pp.580-585
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    • 2009
  • The effects of shear speed and tip height on the high speed shear test of Sn-3.0wt.%Ag-0.5wt.%Cu ball joints were investigated. Solder balls of $450{\mu}m$ in diameter were reflowed at $245^{\circ}C$ on a FR4 PCB (Printed Circuit Board) in order to obtain a sample for the high-speed shear test. The UBM was comprised of Cu/Ni/Au, and the shear speed and tip height varied from 0.5 to 3.0 m/s, and from 10 to $135{\mu}m$, respectively. According to the experimental results, faster shear speed enhanced the shear strength of the solder joints, regardless of the tip height. The fraction of ductile (solder) fracture decreased when the shearing speed was raised from 0.5 to 3.0 m/s. With an increasing tip height from 10 to 50 and $135{\mu}m$, the fracture mode changed from pad lift to mixed (ductile and brittle) and ductile fracture, respectively, while the shearing energy also increased in the same order. The shear energy had a proportional relationship with the fraction of the solder fracture.

$\mu$BGA 솔더접합부의 형상과 수명평가 (Optimal Shape of $\mu$BGA Solder Joints and Thermal Fatigue Life)

  • 신영의;황성진;김종민
    • 한국마이크로전자및패키징학회:학술대회논문집
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    • 한국마이크로전자및패키징학회 2002년도 춘계 기술심포지움 논문집
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    • pp.117-120
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    • 2002
  • In this paper, several methods to predict the solder joint shape are studied. Although there are various methods to predict the solder joint shape, such as truncated sphere method, force-bal tranced analytical solution, and energy-based methods like surface evolver developed by Ken Brakke, we calculate solder joint shape of $\mu$BGA by two solder joint shape prediction methods(truncated sphere method and surface evolver) and then compare results of each method. The results in dicate that two methods can accurately predict the solder joint shape in an accurate range. After that, we calculate reliability solder joint shape under thermal cycle test by FEA program ANSYS. As a result, it could be found that optimal solder joint shape calculated by solder joint prediction method has best reliability in thermal cycle test.

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