本研究主要藉由SEM與EPMA分析觀察鍍鈀/金銅線及合金型銅鈀線在可靠度測試過後，在銅球內部的鈀元素分佈情形與銅-鋁介面的介金屬化合物生長情形間之關係。研究發現，當進行高溫儲存測試(HTST)後，合金型銅鈀線在介面處的介金屬化合物生長速率會快過鍍鈀/金銅線，這可能由於銅-鋁間介金屬化合物生長速率主要受限於銅原子的擴散速率，在EPMA的量測後可發現，合金型銅鈀線不論在測試前後，銅球內之鈀元素皆以非常均勻的形式固溶於其中，相較於測試後鈀原子往球肩處堆積的鍍鈀/金銅線，抑制銅原子擴散進入鋁墊的能力更佳，所以也造成兩者在介面處介金屬化合物生長速率的差別。而在高加速溫溼試驗(HAST)中，銅-鋁介面之介金屬化合物成長速率則都偏低，甚至經過長時間測試後鋁墊仍清晰可見，顯示無論是以電鍍或是摻雜的方式加入鈀元素至銅線中，在此一試驗下，介金屬化合物的生長都能得到一定程度的抑制。較慢的銅-鋁間介金屬化合物生長速率及特定的界金屬相生成都有助於避免介面處裂縫生成及接點性質提升，故合金型銅鈀打線的開發對於改善打線接合處的可靠度性質有正面的幫助，未來或可成為打線的主流材料之一。

In this study, we investigated the effect of Pd distribution on the interfacial reactions for copper wire bonding under reliability tests utilizing SEM and EPMA.
From the results of HTST, we can find that the growth rate of IMCs of Pd-alloyed copper wire bonds is slower than that of Pd/Au-coated ones near the bond interface. This is probably because the dominate diffusion species in Cu-Al IMCs is copper. EPMA shows that in the Pd-alloyed Cu wire bond, the Pd was uniformly distributed in the copper bond both at the as-bonded step and the tested step. On the other hand, for the Pd/Au-coated Cu wire bond, Pd tends to gather at the ball shoulder rather than the Cu-Al interface. This might be the reason why Pd-alloyed copper wires show better performance of restraining IMCs growth than Pd/Au-coated copper wires.
In the other reliability test, HAST, both the Pd-alloyed copper and Pd/Au-coated copper wires perform greatly restraining the growth of Cu-Al IMCs.
In our research, Pd-alloyed copper wires impede the IMC growth even better than Pd-coated copper wires, having the potential of becoming the mainstream wire bonding material.

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