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pISSN : 1598-706X / eISSN : 2288-8381


(논문)연구논문

한국주조공학회지 (22권2호 89-96)

The Microstructure and Interfacial Reaction between Sn-3.5wt.%Ag-1wt.%Zn and Cu Substrate

Sn-3.5wt.%Ag-1wt.%Zn 땜납과 Cu기판간의 미세조직 및 계면반응

Dae-Hwa Baek, Youn-Jong Seo, Kyung-Ku Lee*, Doh-Jae Lee**

Kwangju Chonnam Regional Small and Medium Business Ofice, *PROMEDI, co., **Chonnam National Univ.

Abstract

This study examined the effects of adding Zn to Sn-3.5Ag solder on the microstructure changes and behavior of interface reaction of the solder joint with Cu substrate. The solder/Cu joints were examined with microscope to observe the characteristics of microstructure changes and interfacial reaction layer with aging treatment for up to 120 days at 15oC. Results ofthe microstructure changes showed that the microstructures were coarsened with aging treatment, while adding 1%Zn suppresses coarsening micro- structures. The Sn-3.5Ag/Cu had a fast growth rate of the reaction layer in comparison with the Sn-3.5Ag-lZn at the aging temperature of 150°C. Through the SEM/EDS analysis of solder joint, it was proved that intennetallic layer was C13Sn5 phase and aged specimens showed that intermetallic layer grew in proportion to V2, and the precipitate of Ag3Sn occur to both inner layer and interface of layer and solder. In case of Zn-containing composite solder, CgSn5 phase formed at the side of substrate and Cu-Zn-Sn phase formed at the other side in double layer. It seems that Cu-Zn-Sn phase formed at solder side did a roll ofba- rier to suppress the growth ofthe CU6SI'15 layer during the aging treatment.

Keywords

Sn-3.5Ag-1Zn, Pb-free Solder, Cu Substrate, Interfacial Reaction