銅線除了成本低，還有優良的導電性及導熱性，在打線接合製程中有逐漸取代金線的趨勢，本研究以銅線實際應用在封裝製程為基準，探討銅線氧化組織變化及界面接合通電特性分析。首先，銅線本身的氧化會導致放電結球時大量的氧原子溶入銅球內，造成結球組織出現樹枝狀結構，此外，氧化時所產生的氧化物 (Cu2O) 使得銅線結球端整體的硬度上升，當銅球在下壓至鋁基板接合時，可能使基板容易破裂而導致接合不良。
本研究將市面上常用的兩種封裝樹脂1702HF及G770與銅線經過長時間的封裝測試960小時 (PCT 熱處理) 後發現，1702HF樹脂與銅線無明顯的界面層生成，而G770樹脂與銅線間有界面層生成，其生成原因為G770樹脂內部是屬於酸性環境，在此環境下樹脂中所含濕氣易與銅線反應生成界面層，此界面層的主要成分為Cu2O，界面層硬度及厚度分別為8~10 GPa 及0.5μm。樹脂界面層的厚度大小能決定銅線的有效截面積，可能直接地影響銅線的導電性。
最後，將銅線打線接合在鋁基板上後，本研究進行一系列的通電試驗，實驗結果顯示通電前後銅線的抗拉強度及接合強度均無太大改變。另外，即使在通電5小時後，銅線與鋁基板接合界面處並無觀察到IMC層生成及電遷移的現象。

Besides cost advantage, copper possesses higher electrical and thermal conductivity than gold. In wire bonding process, there is a trend using copper wire to replace gold wire. The aim of this study is to investigate the oxidized microstructure and bonding electrification characteristic of fine copper wire in the package process. When copper wire oxidizes, a large number of oxygen atoms dissolve into a copper ball during EFO process. The oxidation zone and dendritic structure were found in the oxidized ball composed of Cu and Cu2O. Because of Cu2O, the hardness of the oxidized ball is higher than non-oxidized. This may lead to the rupture of Al substrate and its poor bonding to copper wire.
In this study, after 960 hours of PCT thermal treatment between copper and two common resins, G770 and 1702HF, no obvious interface layer was found between 1702HF and copper but an interface layer could be observed between G770 and copper because of the resin’s low PH and moisture. The thickness and hardness of interface layer are 0.5μm and 8~10 GPa respectively. However, due to the interface layer, the decreased cross section of copper wire could reduce the electrical conductivity of copper wire.
As IMC layer and electro-migration could result in the reduced toughness of copper wire and its bondability to Al substrate, an electrical current was applied for five hours to test the bonding. In this study, there were no apparent variation in the pull strength and bonding strength of copper wire after applying electrical current. Moreover, also no IMC layer and electro-migration was observed in the Cu/Al bonding interface.

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