近年來，許多研究透過添加第四元元素於錫銀銅銲料、改變銲料或覆晶下金屬塊(under bump materialization, UBM）成份，嘗試去改善錫銀銅銲料于使用上的缺憾。除了改變銲料或是覆晶下金屬塊的材料系統之外，亦有學者針對覆晶下金屬塊的方向性及結構做探討。但是具有不同結構的基材(substrate）其經過回焊(reflow)後的界面反應機制尚未詳細討論。介金屬化合物(intermetallic compound)的成長及基材的消耗速率會受到基材的製造方式、方向性及結構影響。因此本實驗的目的希望利用具有不同晶粒大小且無優選方向性的銅基板研究不同結構的銅基板經過回焊後的界面反應差異，嘗試找出基板結構對界面反應之影響因素。
利用銅塊材在400oC下經過不同退火時間及電鍍銅晶板於不同功率下鍍製得到具有不同晶粒大小的銅基板，復以電子背向散射繞射儀(EBSD)分析銅晶板的晶粒大小。電子背向散射繞射儀除了可用以分析晶粒大小外，其極圖（pole figure）、反極圖（inverse pole figure）並搭配X-Ray繞射分析（X-Ray Diffraction）可進一步確認銅基板是否優選方向性。銅基板製備完後，在250oC下和純錫回焊並利用場發射掃描式電子顯微鏡（Field-Emission Scanning Electron Microscope）觀察其界面反應。
透過上述實驗觀察，可量測其介金屬化合物的厚度並進一步計算銅基板之消耗速率。同時介金屬化合物生成反應之級數（reaction order）也可用以說明介金屬化合物的成長情形。同時亦探討Kirkendall void的生成及其對界面反應之影響。因此在本實驗中，得以透過實驗結果及理論討論闡述具有不同晶粒大小之銅基板經過回焊後，造成其界面反應差異之影響因子。

In recent years, many studies have aimed to improve the characteristics of SAC solders by adding fourth element in SAC solder, changing to another solder alloy system, or modifying the material of under bump materialization (UBM). Besides the material selection in both solder ball and UBM, the effect caused by different substrate orientation and the reaction between column structure and intertwined structure was also demonstrated. However, the mechanism of interfacial reaction owing to various substrate structure after reflow was not discussed clearly. It is noted that the intermetallic compounds (IMC) growth and the substrate consumption are affected by factors, such as substrate fabrication, substrate orientation, and substrate structure. Hence, the purpose of this study is to investigate the effect of Cu substrate structural difference on interfacial reaction after reflow with pure Sn solder with various time. To simplify the material systems, polycrystalline Cu substrate with different grain size was applied in this study and reflowed with pure Sn solder.
Both bulk Cu substrate and electroplated Cu substrate were used in this study. Bulk Cu substrate was annealed at 400oC for various time and electroplated Cu substrate was prepared by different duty cycle to achieve different grain size of Cu substrate. Electron Back-Scatter Diffraction (EBSD) was provided to evaluate the grain size of Cu substrate. The pole figure and inverse pole figure by EBSD and X-Ray Diffraction (XRD) were used to confirm that there was not any preferred orientation in the Cu substrate. After Cu substrate reflow with pure Sn at 250oC, a Field-Emission Scanning Electron Microscope (FE-SEM JSM-7600F, JEOL, Japan) was applied to observe the interfacial reaction.
The thickness of IMCs was measured and averaged to evaluate the consumption rate of Cu substrate. The reaction order of IMCs was also computed to illustrate the growth of IMCs. The Kirkendall void formation and its influence was also discussed. Combining the experiment verification and theoretical discussion, the effect of Cu substrate with different grain size on interfacial reaction after reflow with pure Sn solder was demonstrated.

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