錫與鈷銅合金基材之界面反應

Interfacial Reactions between Sn and Co-Cu Substrates

郭俊毅(Chun-Yi Kuo) ； 王朝弘(Chao-Hong Wang)

《興大工程學刊》 21卷2期 (2010/07) Pp. 55-64

https://doi.org/10.6287/JENCHU.2010.2102.01

摘要

本研究探討純Sn銲料與Co-30wt%Cu、Co-50wt%Cu及Co-70wt%Cu合金之固／固及液／固界面反應，基材爲富Co相與富Cu相之混合基材。固／固界面反應中，Sn與富Co、富Cu相反應分別生成CoSn3相及(Cu,Co)6Sn5相。由於富Cu相消耗速率較富Co相快，因此界面呈現不規則。當基材Cu量較低時，反應層以CoSn3相爲主，其中夾雜少許(Cu, Co)6Sn5，隨著Cu含量逐漸提高，轉而生成以(Cu, Co)6Sn5相爲主。另一方面，在液／固界面反應中，液態銲料與富Cu相反應，使得Cu快速溶入銲料中。在反應初期，僅生成層狀CoSn3相，並無(Cu, Co)6Sn5相。長時間反應後，Sn/Co-70wt%Cu明顯生成(Cu,C o)6Sn5，可能是銲料中Cu達至飽和。文章中將更詳盡地探討反應之界面演變。

關鍵字

無鉛銲料 ； 界面反應 ； 錫 ； 鈷銅合金

並列摘要

The interfacial reactions of Sn and Co-Cu alloy substrate were investigated. Three different Co-Cu alloys, Co-30wt%Cu, Co-50wt%Cu and Co-70wt%Cu, were prepared. The Co-Cu alloys are a mixture of Cu-rich and Co-rich phases. The solid-solid reactions were performed first at 200℃. One uniform reaction phase layer composed of a two-phase mixture was observed. The major diffusion element, Sn, reacts with either the Co-rich or Cu-rich phase and then produces CoSn3 and (Cu, Co) 6Sn5, respectively. After the reaction, the substrate boundary appears to be irregular. This is because Cu has a faster consumption rate than Co. The ratio of the two formed phases depends on the alloy composition. For the substrate with less Cu content, the major phase layer is CoSn3, together with a small amount of (Cu, Co) 6Sn5. With higher Cu content, the amount of (Cu, Co) 6Sn5 gradually increases. The liquid-solid Sn/Co-Cu reactions were conducted next at 250°C. The Cu-rich phase dissolves into the molten Sn. Only a CoSn3 phase was formed, even though the Cu content is as high as 70wt%. With longer reaction time, the (Cu, Co) 6Sn5 phase forms in the Sn/Co-70wt%Cu because the Cu in the solder reaches saturation. The interfacial evolutions of the Sn/Co-Cu reactions are discussed in detail.

並列關鍵字

lead-free solders ； interfacial reaction ； Sn ； Co-Cu alloy