摘要 用Sn、Sn0.7Cu、Sn3.0Cu 三種銲料，製作成Cu/Solder/Cu 覆晶式結構，於電流密度104amp/cm2，環境溫度分別為155oC、180oC、與200oC下，進行電遷移效應下誘發銅墊層消耗動力學機制之研究。實驗結果發現陰極端銅墊層消耗是由於電遷移效應下使得銲料中銅原子快速遷移至陽極端，造成接近陰極端介金屬化合物的銲料處，有極低的銅濃度。與陰極端介金屬化合物形成濃度梯度，介金屬化合物因而溶解，誘發陰極端銅墊層消耗。隨著銲料銅濃度的添加，電遷移效應導致銅墊層消耗的現象逐漸減緩。Sn、Sn0.7Cu 與Sn3.0Cu 三種銲料，銅墊層消耗之活化能分別為0.68eV、0.72eV、0.73eV。另外， Cu/Sn/Cu系統失效的臨界溫度被估計出來約為55.3oC。當溫度高於55.3oC 時電遷移效應會造成陰極端銅墊層溶解，低於55.3oC 陰極端則會產生孔洞。 To study the kinetics of Cu dissolution induced by electromigration,we produce a flip chip structure by connecting two Cu foil with a solder bump. Three different Sn-Cu solders are studied which are Sn, Sn0.7Cu,and Sn3.0Cu. The solder bumps are stressed by current density of 104(amp/cm2) at three elevated temperatures, which are 155 ºC, 180 ºC,and 200ºC. The result shows that electromigration will cause the consumption in the cathode Cu pad. It is because that once Cu atoms dissolve into Sn, they are transported to the anode interface quickly. Hence, the solubility of Cu in Sn near the interface between IMC and Sn at the cathode side is always maintain unsaturated. We conclude that the dissolution process of Cu into Sn controls the Cu foil consumption. The activation energy of EM-induced Cu consumption of three solders, Sn, Sn0.7Cu, Sn3.0Cu, is about 0.68eV, 0.72eV,and 0.73eV respectively. Adding Cu into Sn solder can reduce electromigration effect. By the way, a critical temperature that can distinguish two type electromigration failure modes is about 55.3oC. At higher the critical temperature, Cu dissolution induced by electromigration occur the cathode side; at lower critical temperature, voids will form at the cathode side
