Transactions of the Korean Society of Automotive Engineers (한국자동차공학회논문집)

The Korean Society of Automotive Engineers (한국자동차공학회)
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Evaluation of Shear Strength for Pb-free Solder/Ni and Cu Plate Joints due to Reflow Time

리플로우 시간에 따른 Pb-free 솔더/Ni 및 Cu 기판 접합부의 전단강도 평가

  • Ha, Byeori (Advanced Technology Research Team, Jeonbuk Institute of Automotive Technology) ;
  • Yu, Hyosun (Mechanical System Engineering, Chonbuk National University) ;
  • Yang, Sungmo (Mechanical System Engineering, Chonbuk National University) ;
  • Ro, Younsik (Advanced Technology Research Team, Jeonbuk Institute of Automotive Technology)
  • 하벼리 (전북자동차기술원 융복합기술연구실) ;
  • 유효선 (전북대학교 기계시스템공학부) ;
  • 양성모 (전북대학교 기계시스템공학부) ;
  • 노윤식 (전북자동차기술원 융복합기술연구실)
  • Received : 2012.09.10
  • Accepted : 2012.10.18
  • Published : 2013.05.01
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Abstract

Reflow soldering process is essential in electronic package. Reflow process for a long time results from the decrease of reliability because IMC is formed excessively. Solder alloys of Sn-37Pb and Sn-Ag with different kinds of Cu contents (0, 0.5 and 1 wt.%) as compared with Ni and Cu plate joints are investigated according to varying reflow time. The interfaces of solder joints are observed to analyze IMC (intermetallic compound) growth rate by scanning electron microscope (SEM). Shear test is also performed by using SP (Share-Punch) tester. The test results are compared with the solder joints of two different plates (Ni and Cu plate). $Cu_6Sn_5$ IMCs are formed on Cu plate interfaces after reflows in all samples. Ni3Sn4 and $(Cu,Ni)_6Sn_5$ IMCs are also formed on Ni plate interfaces. The IMC layer forms are affected by reflow time and contents of solder alloy. These results show that mechanical strength of solder joints strongly depends on thickness and shape of IMC.

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References

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