| Abstract: | 摘 要
電子構裝業中常使用到的基材材料為銅、鎳、銀為主。在銲接製程中，因銲點中因組成(化學勢)的差異引起銲料與基材原子的相互擴散，加上區域平衡(local equilibrium)的存在，於是乎於界面生成脆性之介金屬化合物，此一脆性之介金屬化合物雖然提供異質材料間的接合，但此介金屬化合物厚度大小卻也提供可靠度之不確定性。除此之外，銲料中微量添加物對銲料性質、界面反應等也是相當重要的因子。因此，本研究主要針對Sn-3.0Ag-0.5Cu (SAC305)、Sn-4.0Ag-0.5Cu (SAC405)以及Sn-4.0Ag-0.5Cu-0.05Ni-0.01Ge (SACNG)三種無鉛銲料與球閘式陣列構裝中之Au/Ni/Cu凸塊下金屬層(UBM)多層結構之界面反應以及其界面之剪力強度。
在界面反應部份，結果顯示三種銲料所生成之介金屬相為(Cu,Ni,Au)6Sn5、(Ni,Cu,Au)3Sn4和AuSn4生成相；經長時間固態熱處理後，界面生成相仍為(Cu,Ni,Au)6Sn5和(Ni,Cu,Au)3Sn4生成相為主，但AuSn4生成相卻隨著反應時間增加而漸漸減少；另外Sn-4.0Ag-0.5Cu-0.05Ni-0.01Ge (SACNG)銲料在所有的反應過程中皆沒有發現以Ge為主的介金屬相生成，Ge的添加並不改變反應生成相之種類。在剪力強度部份，剪切強度隨著時效熱處理時間增加而下降。此外比較銲料間剪切強度之差異，SACNG銲料在長時間時效熱處理過後降幅強度要比SAC305、SAC405銲料要來的小；SAC305、SAC405銲料銲料在熱處理期間，斷裂面從銲料-介金屬化合物處轉變成只有單介金屬化合物，而在SACNG中卻沒有如此轉變。另外，比較觀察其銲料斷裂面之介金屬化合物皆為(Cu,Ni,Au)6Sn5相，並無明顯之差異。
Abstract
Element of Cu、Ni and Ag as substrate have been widely used for electronic packaging industry. In bonding process, the element diffusion between solders and substrate will grows brittle intermetallic compound (IMCs) at the interface. Because it has different compositions and local equilibrium inside. The IMCs provides heterogenous connection； however, the reliability is affected by the thickness of IMCs .An addition of little element in solders is important factor for solder properties and interfacial reaction. Therefore, this study investigate interfacial reaction and reliability between Sn-3.0Ag-0.5Cu (SAC305)、Sn-4.0Ag-0.5Cu (SAC405) 、Sn-4.0Ag-0.5Cu-0.05Ni-0.01Ge (SACNG) and Au/Ni/Cu substrate .
In the interfacial reaction, (Cu,Ni,Au)6Sn5 and (Ni,Cu,Au)3Sn4 phases were formed at the interface, while the AuSn4 phase was observed within the solders in all couples. After heating treatment, (Cu,Ni,Au)6Sn5 and(Ni,Cu,Au)3Sn4 phases were observed to at the interface, but the AuSn4 phases vanished gradually with increasing reaction time. In all reaction process no Ge element IMCs were formed at the interface and within solders in Sn-4.0Ag-0.5Cu-0.05Ni-0.01Ge (SACNG). With respect to reliability, the strength decreased as the time of heating treatment increased. After heating treatment, the strength of SACNG solder was higher that those of SAC305 and SAC405. Furthermore, The fracture morphologies of SAC305 and SAC405 were transformed form solder-IMCs to IMCs only, nevertheless in SACNG, no such transformed was observed. The IMCs of fracture were(Cu, Ni)6Sn5 phase in all solders. |
