Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

The Korean Microelectronics and Packaging Society (한국마이크로전자및패키징학회)
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Effects of Bonding Conditions on Mechanical Strength of Sn-58Bi Lead-Free Solder Joint using Thermo-compression Bonding Method

열압착 접합 조건에 따른 경·연성 인쇄회로기판 간 Sn-58Bi 무연솔더 접합부의 기계적 특성

  • Choi, Ji-Na (School of Advanced Materials Science and Engineering, Sungkyunkwan University) ;
  • Ko, Min-Kwan (School of Advanced Materials Science and Engineering, Sungkyunkwan University) ;
  • Lee, Sang-Min (SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University) ;
  • Jung, Seung-Boo (School of Advanced Materials Science and Engineering, Sungkyunkwan University)
  • 최지나 (성균관대학교 신소재공학부) ;
  • 고민관 (성균관대학교 신소재공학부) ;
  • 이상민 (성균나노과학기술원) ;
  • 정승부 (성균관대학교 신소재공학부)
  • Received : 2013.03.18
  • Accepted : 2013.06.14
  • Published : 2013.06.30
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Abstract

We investigated the optimum bonding conditions for thermo-compression bonding of electrodes between flexible printed circuit board(FPCB) and rigid printed circuit board(RPCB) with Sn-58Bi solder as interlayer. In order to figure out the optimum bonding conditions, peel test of FPCB/RPCB joint was conducted. The peel strength was affected by the bonding conditions, such as temperature and time. The fracture energies were calculated through F-x (Force-displacement) curve during peel test and the relationships between bonding conditions and fracture behaviors were investigated. The optimum condition for the thermo-compression bonding with Sn-58Bi solder was found to be temperature of $195^{\circ}C$ and time of 7 s.

본 연구에서는 Sn-58Bi 솔더를 이용한 경성 인쇄 회로 기판 (Rigid printed circuit board, RPCB)과 연성 인쇄회로 기판 (Flexible printed circuit board, FPCB) 간의 열압착 접합 시, 접합 조건에 따른 기계적 특성에 대하여 연구하였다. 접합 온도와 접합 시간을 변수로 열압착 접합을 실시하여 $90^{\circ}$ 필 테스트(Peel test)를 통해 접합 강도를 측정하고, 단면과 파단면을 관찰하였다. 접합 온도가 증가할수록 접합 강도가 증가하였으며, 접합 시간에 따른 접합 강도의 변화 또한 관찰할 수 있었다. 접합 시간이 증가하면서 접합부의 파괴에 영향을 미치는 요인이 솔더 층에서 금속간 화합물(Intermetallic compound, IMC) 층으로 변화하는 것을 관찰할 수 있었다. 필 테스트 과정의 F-x(Force-distance) curve를 통해 파괴 에너지를 계산하여 금속간 화합물이 접합 강도에 미치는 영향을 평가하였으며, 본 연구에서 $195^{\circ}C$, 7초 조건이 접합 강도와 파괴 에너지가 가장 높게 나타나는 최적 접합 조건으로 도출되었다.

Keywords

References

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  1. Effect of Aging treatment and Epoxy on Bonding Strength of Sn-58Bi solder and OSP-finished PCB vol.21, pp.4, 2014, https://doi.org/10.6117/kmeps.2014.21.4.097