Zn Concentration Effet on the Interfacial Reaction between Lead-Free Solders and Cu.

• Main Authors: Su-Chun Yang, 楊素純
• Other Authors: 鄭紹良, 高振宏
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/43889647669543677714

碩士 === 國立中央大學 === 化學工程與材料工程研究所 === 95 === The acute Zn concentration sensitivity of the reaction between Sn-based solders and Cu substrate is reported and explained in this paper. Three Sn-xZn solders (x = 0.5, 0.7, and 2 wt. %) were reacted with Cu substrates at 250oC for 2-10 mins. A slight variation in the Zn concentration changed the reaction product formed at the interface. When the Zn concentration was low (x = 0.5 wt. %), the reaction product was Cu6Sn5. When the Zn concentration was slightly increased to 2 wt. %, the reaction product became Cu5Zn8. When Zn concentration was in-between (x = 0.7 wt. %), Cu6Sn5 and CuZn co-existed. The above findings are explained using the Cu–Sn–Zn phase diagram. The implication is that the type of compound forms at the interface can be controlled by adjusting the Zn concentration of the Sn-based solders.