在第二層電子構裝產業中，常使用Cu來當作導線架的材料，而本研究在Cu中添加微量Sn、P元素，形成Cu-6.01wt.% Sn-0.12wt.%P之C5191磷青銅合金，磷青銅合金具有高的強度、耐應力腐蝕，高耐熱等特性，常廣泛應用於電機材料，接著端子。無鉛銲料在IC封裝中也扮演著重要的角色，目前最常使用的無鉛銲料大多都以純Sn為基底，並添加Cu、Ag、Zn 等微量元素之合金銲料。本研究選用：Sn、Sn-3.0wt.%Ag-0.5wt.%Cu 與 Sn-0.7wt.%Cu三種無鉛銲料，與C5191合金基材以液體/固體反應偶形式於反應溫度240、255、270°C下反應0.5至10 h，探討其界面反應，並利用掃描式電子顯微鏡並搭配掃描式電子顯微鏡/能量分散光譜儀來觀察其介金屬相的型態變化與生成之的種類。
研究結果顯示，在240°C、255°C、270°C下反應0.5-10 h，Sn/C5191、SAC/C5191、SC/C5191反應偶界面皆會生成扇貝狀的Cu6Sn5相及層狀的Cu3Sn，隨著時間和溫度的增加，介金屬相(IMC)的厚度也會逐漸增加。
本研究中，此三個系統之介金屬相厚度與反應時間之平方根呈線性關係，探討反應機制可發現其皆為擴散控制所主導。

In the second-layer electronic packaging industry, Cu is often used as the material of the lead frame. In this study, trace elements of Sn and P were added to Cu to form C5191, phosphor bronze alloy(Cu-6.01wt.% Sn-0.12wt.%P). Phosphor bronze alloy has high strength, stress corrosion resistance, high heat resistance and other characteristics, and is often widely used in motor materials and terminals. Lead-free solder also plays an important role in IC packaging. Most lead-free solders are commonly based on pure Sn, and trace elements such as Cu, Ag, and Zn are added. In this study, three kinds of lead-free solders: Sn, Sn-3.0wt.%Ag-0.5wt.%Cu and Sn-0.7wt.%Cu were selected, and they were reacted with C5191 alloy substrate in the form of liquid/solid reaction couple at 240, 255, 270°C three temperatures, and the time from 0.5 to 10 h to investigate the interfacial reaction. We use SEM to observe the surface morphology, and investigate the composition of the IMCs by SEM/EDS and EPMA.
The study results show that the reaction at 240°C, 255°C, and 270°C for 0.5-10 h, Sn/C5191, SAC/C5191, and SC/C5191 reaction couple interfaces will all form scalloped Cu6Sn5 and layered Cu3Sn phase. With the increasing times and temperatures, the thickness of the intermetallic phase (IMC) will gradually increase.
In this study, the thickness of the intermetallic phase in three systems has a linear relationship with the square root of the reaction time, and the reaction mechanism reveals that they are all dominated by diffusion controlled.

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