Zaimi Nur Syahirah Mohamad, Salleh Mohd Arif Anuar Mohd, Abdullah Mohd Mustafa Al-Bakri, Nadzri Nur Izzati Muhammad, Sandu Andrei Victor, Vizureanu Petrica, Ramli Mohd Izrul Izwan, Nogita Kazuhiro, Yasuda Hideyuki, Sandu Ioan Gabriel
Faculty of Chemical Engineering Technology, Universiti Malaysia Perlis (UniMAP), Arau 02600, Perlis, Malaysia.
Center of Excellence Geopolymer & Green Technology (CeGeoGTech), Universiti Malaysia Perlis (UniMAP), Taman Muhibbah, Jejawi, Arau 02600, Perlis, Malaysia.
Materials (Basel). 2022 Apr 8;15(8):2758. doi: 10.3390/ma15082758.
Solder interconnection in three-dimensional (3D) electronic packaging is required to undergo multiple reflow cycles of the soldering process. This paper elucidates the effects of multiple reflow cycles on the solder joints of Sn-3.0Ag-0.5Cu (SAC305) lead (Pb)-free solder with the addition of 1.0 wt.% kaolin geopolymer ceramics (KGC). The samples were fabricated using powder metallurgy with the hybrid microwave sintering method. Apart from using conventional cross-sectioned microstructure imaging, advanced synchrotron real-time in situ imaging was used to observe primary IMC formation in SAC305-KGC solder joints subjected to multiple reflow soldering. The addition of KGC particles in SAC305 suppressed the CuSn IMC's growth as primary and interfacial layers, improving the shear strength after multiple reflow soldering. The growth rate constant for the interfacial CuSn IMC was also calculated in this study. The average growth rate of the primary CuSn IMCs decreased from 49 µm/s in SAC305 to 38 µm/s with the addition of KGC particles. As a result, the average solidified length in the SAC305-KGC is shorter than SAC305 for multiple reflow soldering. It was also observed that with KGC additions, the growth direction of the primary CuSn IMC in SAC305 changed from one growth to two growth directions. The observed results can be attributed to the presence of KGC particles both at grains of interfacial CuSn IMCs and at the surface of primary CuSn IMC.
三维（3D）电子封装中的焊点需要经历多次焊接过程的回流循环。本文阐述了多次回流循环对添加了1.0 wt.%高岭土地聚物陶瓷（KGC）的Sn-3.0Ag-0.5Cu（SAC305）无铅焊料焊点的影响。采用粉末冶金结合混合微波烧结法制备样品。除了使用传统的横截面微观结构成像外，还使用了先进的同步加速器实时原位成像来观察在多次回流焊接的SAC305-KGC焊点中初生金属间化合物（IMC）的形成。在SAC305中添加KGC颗粒抑制了作为初生层和界面层的CuSn IMC的生长，提高了多次回流焊接后的剪切强度。本研究还计算了界面CuSn IMC的生长速率常数。添加KGC颗粒后，初生CuSn IMC的平均生长速率从SAC305中的49 µm/s降至38 µm/s。因此，对于多次回流焊接而言，SAC305-KGC中的平均凝固长度比SAC305短。还观察到，添加KGC后，SAC305中初生CuSn IMC的生长方向从一个生长方向变为两个生长方向。观察到的结果可归因于在界面CuSn IMC晶粒处以及初生CuSn IMC表面均存在KGC颗粒。
