本實驗選用不同成份Cu添加的三種錫銅焊料，Sn0.2Cu、Sn0.7Cu及Sn1Cu，分別迴焊於化鎳鈀金(ENEPIG)以及化鎳金(ENIG)兩種基材上，通以電流密為10000A/cm2的電流。觀察電遷移效應對於不同墊層陰極消耗的現象，及界面介金屬化合物之影響，實驗溫度為150℃，實驗時間從0小時到220小時。經電遷移效應後，我們發現不論對哪一種墊層，與銅濃度的錫銅焊料（ex: Sn1Cu）焊接之墊層呈現較明顯抗電遷移現象，因為生成在介面的三元的（Cu,Ni）6Sn5界金屬化合物擁有較穩定的層狀結構；而且，在高銅濃度的錫銅焊料與ENEPIG墊層反應之下，因電遷移導致的陰極鎳層消耗，相對於ENIG墊層相比會比較緩和；反之，在低銅濃度的錫銅焊料的情況，兩種墊層在陰極墊層的消耗值卻與高銅焊料的結果相反，因此，推斷ENEPIG中的無電鍍鈀是主要的原因，特別是無電鍍鈀與不同錫銅焊料反應下會造成不同的介面金屬化合物的形態及結構，例如:介面處在反應後是否生成三元的（Pd,Ni）Sn4相，若是有生成此種相會造成Ni原子的消耗以達到此相的三元穩定態，但若在與高銅添加的焊料反應下，根據相圖便不會有此（Pd,Ni）Sn4相的生成，因此依據銅濃度的多寡有不同的介面相產生。In this study, we investigated the EM effect on the joint interfaces of the Pb-free Sn(Cu) solder/ENEPIG solder joints at different annealing temperatures. The applied current density is 104 A/cm2. The compositions of Sn(Cu) solders joined with ENEPIG pad are SnxCu (x=0.2,0.7,1). According to the preliminary results, a serious EM-induced Ni(P) consumption occurred. With increasing of the Cu content in the Sn(Cu) solders, the resistance to the EM-induced Ni(P) consumption wound be enhanced. In other words, the more Cu content in the Sn(Cu) solders, the less consumption of the ENEPIG pad. Also , we study the EM effect on the ENIG bond-pads joined with the same Sn(Cu) solder bumps at the same EM conditions. We found that, as compared to the previous Sn(Cu) ENEPIG results, the degree of the Ni(P) consumption is much serious and it also depends on the Cu content in the Sn(Cu) solder bumps.
