鍍鈀銅線 (Palladium Coated Copper Wire, PCC)為改善銅線易氧化之新穎打線接合材料，保有銅線優點並為電及熱良導體以及能夠抑制接合後界面介金屬化合物 (Intermetallic Compounds, IMCs)生成速率，且在製程成本上也較金線便宜。但是，PCC在放電結球 (Electric Flame-Off, EFO)後鈀原子容易在頸部偏析而造成頸部與球部鈀原子分佈不均導致可靠度下降。因此，本研究針對鍍鈀銅線進行真空熱處理，藉熱擴散 (Thermal Diffusion)使鈀原子進入銅線內部形成鈀網線 (Palladium-Net Wire, PNW)，進一步克服頸部鈀原子偏析現象。最終，比較熱處理前後鍍鈀銅線之放電結球、打線接合及通電機制。
實驗結果顯示，純銅線在大氣中受電及熱效應影響，表面會生成硬脆氧化層並有氧化銅奈米線結構出現，而鍍鈀銅線的氧化情形則趨緩許多，顯示PCC可抑制氧化現象。從原線材之結球拉伸及金相可看出頸部為粗大化之等徑晶且延性下降至5%以下，這將使接合可靠度及自由度下降。經過400℃、450℃及500℃退火後，發現400℃線材表面鈀含量偏高 (仍高於30%)；500℃時線材表面已嚴重變形不適合後續製程。因此，本研究以450℃做為較理想真空退火溫度。
比較熱處理前後線材發現，經450℃退火鍍鈀銅線在接合強度及接合通電方面仍保有原線材優勢，擁有良好的接合力及電性；而頸部金相受熱處理影響呈等軸晶分佈且延性提升到10%。此外，頸部及球部鈀原子分佈情形也較均勻，顯示熱處理之PNW對於提升頸部可靠度有實質幫助並可提升應用性。

In this study, the annealed effect (at 400 ℃~500 ℃ for 30 min) on the tensile mechanical properties and hardness of thin palladium coated copper wires (PCC) Φ =18μm (0.7mil) were investigated. The microstructural characteristics and the mechanical properties before and after an electric flame-off (EFO) were also studied. Results indicated that with annealing temperatures of more than 450 ℃, the wires possessed a fully annealed structure, the tensile strength and the elongation decreased. Through Pd atoms diffusion and equiaxed grains formed in the matrix structure, the PCC wires became the palladium-net wires (PNW). The microstructures of the free air ball (FAB) of the various wires after EFO contained the column-like grains. The column-like grains grew from the heat-affected zone (HAZ) to the Cu ball. From tensile properties, hardness and electrical properties analysis, the 450℃ annealed wires in the neck zones showed the higher reliability than PCC, and retained advantages of PCC, which contained good bondability and IMCs inhibited ability.

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