Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

The Korean Microelectronics and Packaging Society (한국마이크로전자및패키징학회)
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The Effects of UBM and SnAgCu Solder on Drop Impact Reliability of Wafer Level Package

  • Kim, Hyun-Ho (Nano-Information Technology University & Seoul Technopark) ;
  • Kim, Do-Hyung (Nano-Information Technology University & Seoul Technopark) ;
  • Kim, Jong-Bin (Nano-Information Technology University & Seoul Technopark) ;
  • Kim, Hee-Jin (Nano-Information Technology University & Seoul Technopark) ;
  • Ahn, Jae-Ung (Nano-Information Technology University & Seoul Technopark) ;
  • Kang, In-Soo (NEPES Corporation) ;
  • Lee, Jun-Kyu (NEPES Corporation) ;
  • Ahn, Hyo-Sok (Seoul National University of Science and Technology) ;
  • Kim, Sung-Dong (Seoul National University of Science and Technology)
  • Received : 2009.11.25
  • Accepted : 2010.09.24
  • Published : 2010.09.30
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Abstract

In this study, we investigated the effects of UBM(Under Bump Metallization) and solder composition on the drop impact reliability of wafer level packaging. Fan-in type WLP chips were prepared with different solder ball composition (Sn3.0Ag0.5Cu, and Sn1.0Ag0.5Cu) and UBM (Cu 10 ${\mu}m$, Cu 5 ${\mu}m$\Ni 3 ${\mu}m$). Drop test was performed up to 200 cycles with 1500G acceleration according to JESD22-B111. Cu\Ni UBM showed better drop performance than Cu UBM, which could be attributed to suppression of IMC formation by Ni diffusion barrier. SAC105 was slightly better than SAC305 in terms of MTTF. Drop failure occurred at board side for Cu UBM and chip side for Cu\Ni UBM, independent of solder composition. Corner and center chip position on the board were found to have the shortest drop lifetime due to stress waves generated from impact.

Keywords

References

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