| 摘要: | 本研究主要討論無鉛銲料與(Bi,Sb)2Te3基材的界面反應和擴散阻礙層無電鍍鎳磷於銲料與(Bi,Sb)2Te3基材兩者中間的阻擋效果。第一部分為液態銲料與(Bi,Sb)2Te3基材的界面反應，不同銲料內的Sn與Te的反應生成SnTe。第二部分是無電鍍鎳磷與(Bi,Sb)2Te3基材熱處理後的反應，探討介金屬化合物的生成動力學和成分分析，而後再加上與SnAgCu銲料的迴銲反應並進行退火與電遷移作用下介金屬化合物的變化。 Sn-Ag、Sn-Cu、Sn-Ag-Cu與Sn-Ag-Ni內的Ag或Cu元素會與Te-rich相反應生成介金屬化合物， Ag5Te3和CuTe。無電鍍Ni-P/(Bi,Sb)2Te3系統，經過XRD與EPMA定量分析後得知兩者之間的介金屬化合物為Ni50(Bi,Sb,Te)50，此介金屬化合物生成所需的活化能為111kJ/mol。Ni-P/(Bi,Sb)2Te3與銲料Sn3Ag0.5Cu迴銲反應並於不同溫度退火後，介金屬化合物(Cu,Ni)6Sn5與NiTe皆有明顯成長，SnTe不存在於此系統中，Ni-P有效的妨礙Sn與Te彼此交互擴散。Sn3Ag0.5Cu/Ni-P/(Bi,Sb)2Te3/Ni-P/Sn3Ag0.5Cu在通入150℃與1×10^2A/cm2電流密度的作用下，因為熱電效應的影響使得陰極端較熱介金屬化合物較厚，Ni-P層有明顯的消耗，陽極端溫度較低介金屬化合物較薄。 The intermetallic compound SnTe rapidly formed at interfaces between p-type bismuth telluride (Bi,Sb)2Te3 thermoelectric materials and lead-free solders. The intermetallic compound influences the mechanical properties of the joints and the reliability of thermoelectric modules. Various lead-free solder alloys, Sn-3.5Ag, Sn-3Ag-0.5Cu, Sn-0.7Cu, and Sn-2.5Ag-2Ni were used to investigate the interfacial reactions. The results thus obtained that Ag and Cu preferentially diffused into the Te-rich phase in (Bi,Sb)2Te3, so layers of Ag-Te and Cu-Te compounds could not form as an effective diffusion barrier. Electroless nickel-phosphorus was plated at the interfaces to serve as a diffusion barrier, and the (Cu,Ni)6Sn5 compound formed instead of SnTe. Furthermore, the intermetallic compound Ni-Te formed between nickel-phosphorus and (Bi,Sb)2Te3 and also served as a diffusion barrier. A plot of thickness as a function of annealing time yielded the growth kinetics of the intermetallic compounds in thermoelectric material systems. The activation energy for the growth of Ni-Te intermetallic compound is 111kJ/mol. Ni-P/(Bi,Sb)2Te3/Ni-P were used to investigate the behaviors under electromigration. Sn-3Ag-0.5Cu solder were reflowed and acted as the electrodes. The samples current stressed by a current density of 1×10^2A/cm2 at 150℃. The intermetallic compound formed between the solders, Ni-P layer and (Bi,Sb)2Te3. The major compounds at the interface are (Cu,Ni)6Sn5 and NiTe. The thicknesses of the intermetallic compound at the cathode were thicker than at the anode since thermoelectric effect induced a higher temperature at the cathode. |
