Interfacial Reactions in the Ni/Sn-xZn/Cu Sandwich Couples

• Published in: Journal of electronic materials Vol. 45; no. 1; pp. 203 - 211
• Main Authors: Yen, Yee-Wen, Lin, Chung-Yung, Lai, Mei-Ting, Chen, Wan-Ching
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.01.2016; Springer Nature B.V
• Subjects: Alloys; Characterization and Evaluation of Materials; Chemical reactions; Chemistry and Materials Science; Electronics and Microelectronics; Instrumentation; Interfacial bonding; Materials Science; Optical and Electronic Materials; Phase transitions; Solid State Physics; Zn/Cu sandwich couples; Ni/Sn; intermetallic compound; Interfacial reactions
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-015-4220-8

The interfacial reactions in Ni/Sn- x Zn/Cu sandwich couples which were reflowed at 270°C for 1 h and then aged at 160°C for 1–1000 h were investigated. When the 1000- μ m-thick Sn-Zn alloy reacted with Ni and Cu in this couple, the results indicated that the (Ni, Cu) 3 Sn 4 , (Ni, Cu) 5 Zn 21 , and Ni 5 Zn 21 phases were formed at Sn-1Zn/Ni, Sn-5Zn/Ni, and Sn-9Zn/Ni interfaces for 1 h reflowing, respectively. After 1000 h aging, each intermetallic compound (IMC) was converted to (Cu, Ni, Zn) 6 Sn 5 , (Ni, Cu, Sn) 5 Zn 21 /Ni 5 Zn 21 , and Ni 5 Zn 21 (two layers) phases in the related couples. On the Cu side, the Cu 6 Sn 5 phase in the Sn-1Zn/Cu interface and the Cu 5 Zn 8 phase in the Sn-5Zn/Cu and Sn-9Zn/Cu interfaces were observed when the couple was reflowed at 270°C for 1 h. After 100 h aging, the (Cu, Ni, Zn) 6 Sn 5 , Cu 5 Zn 8 /(Cu, Zn) 6 Sn 5 , and Cu 5 Zn 8 phases were formed at the Sn-1Zn/Cu, Sn-5Zn/Cu and Sn-9Zn/Cu interfaces. When the Sn-Zn alloy thickness was decreased to 500  μ m, the (Cu, Ni, Zn) 6 Sn 5 phase at the Sn-1Zn/Ni interface and the (Ni, Cu, Sn) 5 Zn 21 phase at the Sn-5Zn/Ni and Sn-9Zn/Ni interfaces were observed after 1 h reflowing. When the couple was aged at 160°C for 1000 h, each IMC was converted to (Cu, Ni, Zn) 6 Sn 5 and Cu 5 Zn 8 /(Cu, Ni, Sn)Zn/Ni 5 Zn 21 phases at the Sn-1Zn/Ni and Sn-(5, 9)Zn/Ni interfaces. (Cu, Ni, Zn) 6 Sn 5 and Cu 5 Zn 8 were, respectively, formed at the Sn-1Zn/Cu and Sn-(5, 9)Zn/Cu interfaces for 1 h reflowing. After 100 h aging, the IMCs were converted to (Cu, Ni, Zn) 6 Sn 5 and Cu 5 Zn 8 /(Cu, Zn) 6 Sn 5 phases. This current study reveals that the IMC formation in Ni/(Sn- x Zn)/Cu sandwich couples are very sensitive to the Zn concentration and thickness in Sn- x Zn alloys.