Interfacial Reactions of Pb-free Solders/Au/Pd/Ni/Cu and /Au/Pd/Ni/Brass.

• Main Authors: Yang-Kai Fang, 方揚凱
• Other Authors: Yee-Wen Yen
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/69974715218726640513

碩士 === 國立臺灣科技大學 === 化學工程系 === 96 === Pb-free solders have attracted much attention to replace the conventional Sn-Pb solders owing to an environmental issue. Popular lead-free solders are Sn, Sn-3.0Ag-0.5Cu, Sn-0.7Cu, Sn-58Bi and Sn-9Zn (in wt %). Multilayer structures of Au/Pd/Ni/Cu and Au/Pd/Ni/Brass are commonly used in printed circuit boards. This study investigates the interfacial reaction between Pb-free solders and two different kinds of substrates (Au/Pd/Ni/Cu and Au/Pd/Ni/Brass). The reflow temperature was at 240, 255 and 270℃, while the reflow time was varied between 20 minutes and 20 hours. The surface morphology and IMC formation are examined as well. According to experimental results, the IMCs changed from (Ni,Cu)3Sn4 to (Cu,Ni)6Sn5 and Cu3Sn at the interface of Sn/Au/Pd/Ni/Cu couple. In the Sn-3.0Ag-0.5Cu/Au/Pd/Ni/Cu and Sn-0.7Cu/Au/Pd/Ni/Cu couples, there were two IMCs such as (Cu,Ni)6Sn5 and Cu3Sn at the interface. In the Sn-58Bi/Au/Pd/Ni/Cu couple, only a Ni3Sn4 IMC was observed between the solder and Ni layer. In the Sn-9Zn/Au/Pd/Ni/Cu couple, the Pd2Zn9 and NiZn phases were formed at the interface. After reflow for 4 hours, the Pd2Zn9, NiZn, and Ni5Zn21 phases were formed at the interface. On the other hand, there were two IMCs such as (Cu,Ni)6Sn5 and CuZn at the interface which are in the Sn/Au/Pd/Ni/Brass, Sn-3.0Ag-0.5Cu/Au/Pd/Ni/Brass, and Sn-0.7Cu/Au/Pd/Ni/Brass couples respectively. In the Sn-58Bi/Au/Pd/Ni/Brass couple, only a Ni3Sn4 IMC was observed between the solder and Ni layer. Until the reaction time of 8 hours, the (Ni,Cu)3Sn4, (Cu,Ni)6Sn5, and CuZn phases were formed at the interface. In the Sn-9Zn/Au/Pd/Ni/Brass couple, the Pd2Zn9 and Ni5Zn21 phases were formed at the interface. After reflow for 20 hours, the CuZn5, Pd2Zn9, Ni5Zn21, and Cu5Zn8 phases were formed at the interface.