Journal of Welding and Joining

  • 제23권3호
  • /
  • Pages.61-67
  • /
  • 2005
  • /
  • 2466-2232(pISSN)
  • /
  • 2466-2100(eISSN)
대한용접접합학회 (The Korean Welding and Joining Society)
권호 표지

Sn-Bi도금 $Sn-3.5\%Ag$ 솔더를 이용한 Capacitor의 저온 솔더링

Lower Temperature Soldering of Capacitor Using Sn-Bi Coated $Sn-3.5\%Ag$ Solder

  • 김미진 (서울시립대학교 신소재공학과) ;
  • 조선연 (서울시립대학교 신소재공학과) ;
  • 김숙환 (포항산업과학연구원 용접센터) ;
  • 정재필 (서울시립대학교 신소재공학과)
  • Kim Mi-Jin (Dept. of Materials Science and Engineering, University of Seoul) ;
  • Cho Sun-Yun (Dept. of Materials Science and Engineering, University of Seoul) ;
  • Kim Sook-Hwan (Welding Centre, RIST) ;
  • Jung Jae-Pil (Dept. of Materials Science and Engineering, University of Seoul)
  • 발행 : 2005.06.01
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

Since lead (Pb)-free solders for electronics have higher melting points than that of eutectic Sn-Pb solder, they need higher soldering temperatures. In order to decrease the soldering temperature we tried to coat Sn-Bi layer on $Sn-3.5\%Ag$ solder by electroplating, which applies the mechanism of transient liquid phase bonding to soldering. During heating Bi will diffuse into the $Sn-3.5\%Ag$ solder and this results in decreasing soldering temperature. As bonding samples, the 1608 capacitor electroplated with Sn, and PCB, its surface was finished with electroless-plated Ni/Au, were selected. The $Sn-95.7\%Bi$ coated Sn-3.5Ag was supplied as a solder between the capacitor and PCB land. The samples were reflowed at $220^{\circ}C$, which was lower than that of normal reflow temperature, $240\~250^{\circ}C$, for the Pb-free. As experimental result, the joint of $Sn-95.7\%Bi$ coated Sn-3.5Ag showed high shear strength. In the as-reflowed state, the shear strength of the coated solder showed 58.8N, whereas those of commercial ones were 37.2N (Sn-37Pb), 31.4N (Sn-3Ag-0.5Cu), and 40.2N (Sn-8Zn-3Bi). After thermal shock of 1000 cycles between $-40^{\circ}C$ and $+125^{\circ}C$, shear strength of the coated solder showed 56.8N, whereas the previous commercial solders were in the range of 32.3N and 45.1N. As the microstructures, in the solder $Ag_3Sn$ intermetallic compound (IMC), and along the bonded interface $Ni_3Sn_4$ IMC were observed.

키워드

참고문헌

  1. J. Glazer. J. Elec. Mater.. 23-8 (1994), 673
  2. W.J. Plumbirdge et al.. J. Elec. Mater.. 30. (2001) 1178 https://doi.org/10.1007/s11664-001-0147-3
  3. C.H. Reader et al.. J. Elec. Mater.. 28 (1999). 1045 https://doi.org/10.1007/s11664-999-0182-z
  4. X.Qiao et al., Mater. Sci. Eng A283. 2000. 38 https://doi.org/10.1016/S0921-5093(00)00621-3
  5. T.M. Korhonen et al.. IEEE Trans. on Adv. Pack. 24-4. (2001) 515 https://doi.org/10.1109/6040.982838
  6. J.S. Lee et al.. Material transactions,45. (2004). 783 https://doi.org/10.2320/matertrans.45.783
  7. S. Kou: Welding Metallurgy. Wiley-Interscience. N.J.. 2003
  8. I.T. Poku et al., Metall. Trans. A19A. 675 (1988)
  9. E. Lugscheider et al.. Surf. Coat. Tech. 704 (2003). 174
  10. Min-Suk Suh et al., J. Kor. Inst. Met. & Mater, 40 (2002), 74
  11. Akio Hirose et al., Material transaction, 42-5 (2001), 794 https://doi.org/10.2320/matertrans.42.794
  12. Thaddeus B. Massalski : Binary alloy phase diagrams American society for metals. Ohio. 1986
  13. J. S. Hwang : environment-frendliy electronics: Lead-free technology Electrochemical publications ltd. 2001
  14. A.C.Tan : Tin and Solder Plating in the semiconductor Industry, Chapman & Hall. London. 1993, 23
  15. W.J. Tomlinson et al .. J. Mater. Sci. 22 (1987). 1835 https://doi.org/10.1007/BF01132413
  16. T. Reinikainen et al.. Metallug, Trans. A, 30A (1999). 123
  17. L. Xiao et al.. IEEE International Symposium on Advanced Packaging Materials. 2000. 145 https://doi.org/10.1109/ISAPM.2000.869259