Growth characteristics and formation mechanisms of Cu6Sn5 phase at the liquid-Sn0.7Cu/(111)(Cu) and liquid-Sn0.7Cu/(001)(Cu) joint interfaces
Growth characteristics and formation mechanisms of Cu6Sn5 phase at the liquid-Sn0.7Cu/(111)(Cu) and liquid-Sn0.7Cu/(001)(Cu) joint interfaces
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DOI：
10.1016/j.actamat.2015.11.034
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发表时间：
2016-02
期刊：
影响因子：
9.4
通讯作者：
Zhihao Zhang;Mingyu Li;Zhi-Quan Liu;Sen Yang
中科院分区：
文献类型：
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作者：
Zhihao Zhang;Mingyu Li;Zhi-Quan Liu;Sen Yang
研究了液态Sn0.7Cu/（111）Cu和液态Sn0.7Cu/（001）Cu接头界面上Cu 6Sn 5相的生长特征和形成机制。由于界面环境的作用，在250° C下钎焊1 s-1h后，两种Cu单晶上均生成了具有固定交叉角的屋顶型Cu 6Sn 5晶粒的规则阵列。在液态Sn 0.7Cu/Cu 6Sn 5界面处，Cu 6Sn 5相的生长机制为六角棒状生长，其表面能和粗糙度各向异性。根据这一机制，在（111）和（001）Cu焊盘上形成的Cu 6Sn 5屋顶，无论是否属于Cu 6Sn 5和Cu相的最小失配方向，都始终沿着Cu 6Sn 5相的[0001]方向延伸;反应时间延长至1 h，它们仍分别保持{11 2 <$0}和{10 1 <$0}面为侧面。在Cu 6Sn 5/Cu界面上，根据Cu和Sn 5相的合适匹配，确定了Cu 6Sn 5在Cu单晶上的两种三维排布规则.结果表明，Cu 6 Sn 5屋顶与Cu单晶的连接界面分别为{10 1 <$0}<${111}和{11 2 <$0}<${0 0 1}，两种界面上均存在{0 0 0 1}<${0 11}的平行取向关系。该研究有助于阐明Cu 6Sn 5相的生长机制，为三维集成电路互连应用中Cu 6Sn 5相的取向设计提供科学依据。
This work investigated the growth characteristics and formation mechanisms of the Cu 6 Sn 5 phase at the liquid-Sn 0.7 Cu/(111) Cu and liquid-Sn 0.7 Cu/(001) Cu joint interfaces. As a result of contributions from the interfacial environments, regular arrays of the roof-type Cu 6 Sn 5 grains with fixed intersecting angles were generated on both types of the Cu single crystals after soldering at 250° C for 1 s–1 h. At the liquid-Sn 0.7 Cu/Cu 6 Sn 5 interface, a hexagonal-rod-type growth mechanism for Cu 6 Sn 5 phase was proposed on the basis of its anisotropy in surface energy and roughness. According to this mechanism, the Cu 6 Sn 5 roofs formed on the (111) and (001) Cu pads would consistently elongate in the [0001] direction of Cu 6 Sn 5 phase, regardless of whether they belonged to the minimum mismatch direction of Cu 6 Sn 5 and Cu phases; and they would maintain the {11 2¯ 0} and {10 1¯ 0} planes as the side faces respectively, despite the reaction time being prolonged to 1 h. At the Cu 6 Sn 5/Cu interface, two types of the three-dimensional placement rules for Cu 6 Sn 5 roofs on the Cu single crystals were determined on the basis of the suitable Cu matches of these two phases. Specifically, the junction interfaces between Cu 6 Sn 5 roofs and Cu single crystals were confirmed to be‖{10 1¯ 0}‖{111} and {11 2¯ 0}‖{001}; and the parallel orientation relationships of {0001}‖{011} were always present on both types of interfaces. Our study can help to clarify the growth mechanism of Cu 6 Sn 5 phase and to provide a scientific basis of Cu 6 Sn 5 orientation design for three-dimensional integrated circuit interconnect applications.