在早期封裝產業中經常使用金線做為主要的打線接合材料，然而金線與鋁基板進行接合時容易產生介金屬化合物，且金價近年來居高不下，因此便開始探求其他材料來取代金線，常見的導線有銀線與銅線。銀線雖然具有非常優異的導電性及導熱性，但也容易與鋁生成介金屬化合物，且有電遷移的疑慮；而銅線除了有良好導電性與導熱性、成本具競爭力等優勢外，銅與鋁形成介金屬化合物的速率也較金及銀低。因此，本研究以銅基導線為主題進行導線可靠度的探討。
本研究對銅線添加微量的銀、鈀及金形成創新的銅微合金導線，銀、鈀及金等貴金屬的添加可以提升導線的機械性質與化學穩定性，且微量的添加量可以避免電阻值提升。本研究將藉由機械性質與通電試驗釐清銅微合金導線與目前主流應用的鍍層銅導線在原線材及完成打線接合後的性質差異，並導入氯化試驗評估導線在應用方面的可靠度，透過全方面應用特性比較來評估銅微合金導線能否取代鍍層銅導線。
機械性質方面，添加微量的合金元素所產生的固溶強化可以提升導線的微硬度及拉伸性質，使銅微合金導線整體的機械性質較鍍層銅導線優異。完成打線接合後，銅微合金導線第一銲點的抗拉強度也較高，顯示出良好的接合強度。
通電性質方面，銅微合金導線在通電的前段所量測出的動態電阻值較高，這是因為微量合金元素的添加會造成少量電阻值提高，而當電流提高時，鍍層銅導線會受到更多焦耳熱的影響，鍍層的原子會擴散融進銅線材，導致電阻值快速提升，使其在較低的電流便產生熔斷。通電循環方面，鍍層銅導線因為鍍層與線材的熱膨脹係數差異，在反覆通電受熱時容易產生熱疲勞導致導線失效。
在進行氯化試驗之後，氯離子會沿著銅微合金導線表面的晶界進行攻擊，對導線整體的拉伸性質無明顯影響，但表面的侵蝕會使通電循環壽命下降；鍍層銅導線經過氯化之後則會在表面產生小孔洞，導致拉伸性質劣化，而由於僅在鍍層上產生孔洞，對主要的電子通路影響較小，故通電循環壽命無明顯衰退。
經過一系列的試驗，銅微合金導線具有良好的性質，在機械性質及通電性質方面都優於鍍層銅導線，具有取代鍍層銅導線的應用價值。

關鍵字：銅微合金導線、鍍層銅導線、通電循環、氯化、打線接合

In the early packaging industry, gold wire was often used as the main wire bonding material. However, when the gold wire is bonded to the aluminum substrate, intermetallic compounds are easily generated. In addition, the price of gold has risen in recent years, making the packaging application technology of silver wire and copper wire continue to be reported. Although silver wire has very excellent electrical and thermal conductivity, it is also easy to form intermetallic compounds with aluminum, and there are doubts about electromigration; while copper wire has good mechanical strength, electrical conductivity and thermal conductivity, and the rate of forming intermetallic compounds with aluminum substrates is lower than that of gold wire and silver wire. Therefore, this study takes copper-based wires as the subject to discuss the reliability of wires.
In this study, a trace amount of silver, palladium and gold were added to form innovative micro-alloyed copper wires. Adding noble metal elements can improve the corrosion resistance and oxidation resistance of copper wires, and the content of alloying elements is low, which can avoid the problem of excessive resistance. In this study, the mechanical properties and electrical properties of three micro-alloyed copper wires and the current mainstream coated copper wires were tested to clarify the basic material properties of the original wires and the samples after wire bonding, and then introduce the chlorination test to evaluate the reliability of the wire in application. Evaluate whether micro-alloyed copper wires can replace coated copper wires by comparing all aspects of application characteristics.
In terms of mechanical properties, the solid solution strengthening produced by adding a small amount of alloying elements can improve the microhardness and tensile properties of the wire, making the overall mechanical properties of the micro-alloyed copper wires better than that of the coated copper wire. After wire bonding, the micro-alloyed copper wires also have higher first bond tensile strength than the coated copper wire.
In terms of electrical properties, the addition of trace alloying elements increases the resistances slightly, resulting in higher dynamic resistances of the MAC in the early stage of electrification. When the current increases, the CPA is affected by Joule’s heat, and the palladium atoms of the coating layer diffuse into the wire, causing the resistance to increase rapidly, resulting in a lower fusing current. In terms of power cycling test, due to the difference in coefficient of thermal expansion between the coating layer and the wire, CPA are prone to thermal fatigue and lead to failure of the wire.
After the chlorination test, chloride ions will attack along the grain boundaries on the surface of the micro-alloyed copper wires, which has no obvious effect on the overall tensile properties of the wires, but surface erosion will reduce the electrical fatigue life. After chlorination of the coated copper wire, small holes will be formed on the surface, resulting in deterioration of tensile properties. Since holes are only formed in the plating layer, the main electronic path is less affected, so the electrical fatigue life is not significantly degraded.
After a series of tests, the micro-alloyed copper wires have good properties and are superior to the coated copper wire in terms of mechanical properties and electrical properties. Therefore, it has the application value of replacing the coated copper wire.

Keywords: Micro-alloyed copper wires (MAC), Au/Pd-coated copper wires,
Power cycling, Chlorination, Wire bonding

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