Journal of the Korean Society of Safety (한국안전학회지)

The Korean Society of Safety (한국안전학회)
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Evaluation of the Impact Shear Strength of Thermal Aged Lead-Free Solder Ball Joints

열시효 처리된 무연 솔더 볼 연결부의 충격 전단강도 평가

  • Chung, Chin Sung (R & D Center, Flow Master Co.) ;
  • Kim, Ho Kyung (Department of Mechanical & Automotive Engineering, Seoul National University of Science & Technology)
  • 정진성 ((주)플로마스터 기술연구소) ;
  • 김호경 (서울과학기술대학교 기계.자동차공학과)
  • Received : 2015.07.04
  • Accepted : 2015.10.26
  • Published : 2015.12.31
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Abstract

The present study investigates the impact shear strength of thermal aged Sn-3Ag-0.5Cu lead-free solder joints at impact speeds ranging from 0.5 m/s to 2.5 m/s. The specimens were thermal aged for 24, 100, 250 and 1000 hours at $100^{\circ}C$. The experimental results demonstrate that the shear strength of the solder joint decreases with an increase in the load speed and aging time. The shear strength of the solder joint aged averagely decreased by 43% with an increase in the strain rate. For the as-reflowed specimens, the mode II stress intensity factor ($K_{II}$) of interfacial IMC between Sn-3.0Ag-0.5Cu and a copper substrate also was found to decrease from $1.63MPa.m^{0.5}$ to $0.97MPa.m^{0.5}$ in the speed range tested here. The degradations in the shear strength and fracture toughness of the aged solder joints are mainly caused by the growth of IMC layers at the solder/substrate interface.

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References

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