• Title/Summary/Keyword: Au-embrittlement

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Reaction Characteristics between In-l5Pb-5Ag Solder and Au/Ni Surface Finish and Reliability Evaluation of Solder Joint (In-l5Pb-5Ag 솔더와 Au/Ni Surface Finish와의 반응 특성 및 접합 신뢰성 평가)

  • 이종현;엄용성;최광성;최병석;윤호경;박흥우;문종태
    • Journal of the Microelectronics and Packaging Society
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    • v.9 no.4
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    • pp.1-9
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    • 2002
  • The metallurgical reaction properties between the pad consisted of 0.5 $\mu\textrm{m}$Au/5 $\mu\textrm{m}$Ni/Cu layers on a conventional ball grid array (BGA) substrate and In-15 (wt.%)Pb-5Ag solder ball were characterized during the reflow process and solid aging. During the reflow process of 1 to 5 minutes, it was observed that thin $AuIn_2$ or Ni-In intermetallic layer was formed at the interface of solder/pad. The dissolution rate of the Au layer into the molten solder was about $2\times 10^{-3}$ $\mu\textrm{m}$/sec which is remarkably low in comparison with a eutectic Sn-37Pb solder. After solid aging treatment for 500 hrs at $130^{\circ}C$, the thickness of $Ni_{28}In_{72}$ intermetallic layer was increased to about 3 $\mu\textrm{m}$ in all the conditions nevertheless the initial reflow time was different. These result show that In atoms in the solder alloy were diffused through the $AuIn_2$ phase to react with underlaying Ni layer during solid aging treatment. From the microstructural observation and shear tests, the reaction properties between In-15Pb-5Ag alloy and Au/Ni surface finish were analyzed not to trigger Au-embrittlement in the solder joints unlike Sn-37Pb composition.

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Metallurgical Reaction Properties between In-15Pb-5Ag Solder and Zu-Ni Surface Finish (In-l5Pb-5Ag 솔더와 Au/Ni 층과의 반응 특성)

  • 이종현;엄용성;최광성;최병석;윤호경;박흥우;문종태
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2002.05a
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    • pp.183-188
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    • 2002
  • With the contact pad consisted of $0.5{\mu}{\textrm}{m}$ $Au/5{\mu}{\textrm}{m}$ Ni/Cu layers on a conventional ball grid array(BGA) substrate, metallurgical reaction properties between the pad and In-15(wt.%)Pb-5Ag solder alloy were studied after reflow and solid aging. In as-reflow condition, thin AuIn$_2$or Ni$_{28}$In$_{72}$ intermetallic layer was formed at the solder/pad interface according to reflow time. Dissolution of the Au layer into the molten solder was remarkably limited in comparison with eutectic Sn-37Pb alloy. After solid aging of 300 hrs, thickness of In-Ni layer increased to about $2{\mu}{\textrm}{m}$ in the both as-reflow case. It was observed that In atoms diffuse through the AuIn$_2$phase to react with underlaying Ni layer. The metallurgical reaction properties between In-l5Pb-7Ag alloy and Au/Ni surface finish were analysed to result in suppression of Au-embrittlement in the solder joints.

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