(哈爾濱工業(yè)大學 材料科學與工程學院, 哈爾濱 150001)
摘 要: 采用熔滴直接凸點制作方法， 對共晶SnPb及SnAgCu釬料熔滴與Au/Ni/Cu焊盤所形成的凸點／焊盤界面組織進行了研究，并與激光重熔條件下獲得的凸點／焊盤界面組織進行了比較， 考察了凸點／焊盤界面組織在隨后的再重熔過程中的演變。 結(jié)果表明： 釬料熔滴與焊盤在接觸過程中形成了Au-Sn化合物， Au層并未完全反應。 在隨后的再重熔過程中， Au層被完全消耗， 全部溶入釬料基體中， Ni層與釬料發(fā)生反應。 無鉛釬料（SnAgCu）和SnPb釬料所形成的界面組織明顯不同； 再重熔后SnPb釬料／焊盤的界面組織為Ni3Sn4， SnAgCu釬料／焊盤界面組織為（CuxNi1-x）6Sn5。
關(guān)鍵字: 釬料熔滴； 凸點； 無鉛釬料； 重熔； 金屬間化合物
（School of Materials Science and Engineering,
Harbin Institute of Technology, Harbin 150001, China）
Abstract: The interface structures of solder droplet for SnPb and SnAgCu Al/Ni/Cu pad were investigated by droplet direct laser fabrication method, which is compared with the interface structures for bump and pad under laser reflow bumping. The intermetallics evolution at solder bump/pad interface during subsequent reflow soldering is conducted. The results show that, during the contact reaction between molten solder droplet and pad, Au is dissolved into molten solder droplet and Au-Sn intermetallic compounds are precipitated, while Au doesn-t react with solder droplet fully. During the subsequent reflow soldering, Au layer disappears from the interface, Au-Sn compounds are distributed into solder matrix, and Ni layer is exposed to solder and reacts with solder directly. Distinctive difference exists between the intermetallics formed at Pb-free solder/pad interface and SnPb solder/pad interface during reflow soldering process. For the SnPb solder/pad system, the Ni3Sn4 layer is formed at the solder/pad interface during reflow. For the SnAgCu solder/pad system, the （CuxNi1-x）6Sn5 layer is formed at the solder/pad interface during reflow.
Key words: solder droplet; bump; lead-free solder; reflow; intermetallic compound
