- 學位論文
無鉛銲料與鈀-銀導體之界面反應及錫-鈀-銀三元系統相平衡
Interfacial Reactions between Lead-free Solders and Pd-Ag Conductors and Sn-Pd-Ag Ternary Phase Equilibria
摘要
Ag-Pd合金為常用的厚膜混成電路之導體材料，Sn為無鉛銲料之主要成份，Sn/Ag-Pd為厚膜混成電路於覆晶構裝中常見之銲點結構，Sn-Pd-Ag為重要之電子材料系統。本論文探討Sn/Ag-Pd及Sn-0.7wt.%Cu/Ag-Pd之界面反應，並探討Sn-Pd-Ag三元系統相平衡。在Sn-Pd-Ag三元系統於250oC下之相平衡研究中，共決定出11個單相區、19個兩相區以及9個三相區，其中並無發現三元相。Ag、Pd之間為彼此互溶的固溶相，PdSn2、Pd3Sn2、Pd2Sn、Pd3Sn之最大Ag溶解度分別約為3.6、12.4、19與5.0at.%，Ag4Sn相僅可溶有1.0at.% Pd，其餘介金屬相均無第三元的溶解度。 Sn/Ag-Pd與Sn-0.7wt.%Cu/Ag-Pd之界面反應的生成相結果相同，主要的生成相為PdSn4及PdSn3相。Pd的添加量為10at.%時，生成相為Ag3Sn相；Pd的添加量為20～40at.%時，會生成一層非熱力學穩定的Sn-Pd-Ag之三元相(X相)，為一新發現之生成相。X相為PdSn3及Ag3Sn兩相之混合相，當反應溫度超過350oC，X相就不會生成。在時效測試的反應下，Sn-0.7wt.%Cu/Ag-Pd反應偶會生成X/富Ag-Sn相/PdSn3/富Ag-Sn相/X交錯排列(Alternating)之生成相。 由於商用的Ag-Pd導體為Ag-30at%Pd，而本論文中發現在此比例的Ag-Pd導體，會生成一介穩態相(X相)。此X相的生成可能會直接影響銲點的可靠度，故商用產品之無鉛銲料/Ag-Pd導體之銲點的可靠度有待重新評估。
並列摘要
Ag-Pd conductors are used to be the conductive materials of thick film hybrid circuit, and Sn is the primary element of the Pb-free solders. Sn/Ag-Pd soldering joints are frequently encountered in flip chip packaging of the thick film hybrid circuit. Therefore, the Sn-Pd-Ag ternary system is very important in the electronic packaging. This study investigates the phase equilibria of the Sn-Pd-Ag ternary system and Sn-(0.7wt.%Cu)/Ag-Pd interfacial reactions. The 250oC isothermal section of the Sn-Pd-Ag ternary system is experimentally determined in this study. There are 11 single-phase, 19 two-phase, and 9 three-phase regions. No ternary compound is found. The Ag-Pd region is a (Ag, Pd) soild solution phase. The maximum Ag solubility in the PdSn2 phase is 3.6at%, and those of the Pd3Sn2, Pd2Sn, and Pd3Sn phases are 12.0, 19.0, and 5.0at%, respectively. The maximum Pd solubility in the Ag4Sn phase is 1.0at%. Sn/Ag-Pd interfacial reactions are similar to those of Sn-0.7at.%Cu/Pd-Ag. The primary IMC is the PdSn4 and PdSn3 phase. When the Pd additions are 20-40at%, a meta-stable phase(X) is formed. The X phase is a mixture of the PdSn3 and Ag3Sn phase. The X phase is not formed at higher than 350oC. Under the aging test, alternating reaction phases, X/Ag-Sn/PdSn3/Ag-Sn/X, are formed in Sn-0.7wt%Cu /Ag-Pd couples. The commercial Ag-Pd conductors are Ag-30at%Pd. Since a meta-stable phase is formed, the reliability of the Pb-free solders/Ag-30at%Pd contacts needs to be re-assessed.