微尺寸SnAg凸点的制备技术及其互连可靠性  

Micro-Sized SnAg Solder Bumping Technology and Bonding Reliability

作　　者：林小芹[1] 朱大鹏[1] 罗乐[1] 

机构地区：[1]中国科学院上海微系统与信息技术研究所

出　　处：《Journal of Semiconductors》2008年第1期168-173,共6页半导体学报（英文版）

基　　金：国家自然科学基金资助项目(批准号:60676061)~~

摘　　要：用电镀法制备了尺寸小于100μm的面阵列Sn-3.0Ag凸点.芯片内凸点的高度一致性约1.42%,Φ100mm硅圆片内的高度一致性约3.57%,Ag元素在凸点中分布均匀.研究了不同回流次数下SnAg/Cu的界面反应和孔洞形成机理,及其对凸点连接可靠性的影响.回流过程中SnAg与Cu之间Cu6Sn5相的生长与奥氏熟化过程相似.SnAg/Cu6Sn5界面中孔洞形成的主要原因是相转变过程中发生的体积缩减.凸点的剪切强度随着回流次数的增多而增大,且多次回流后SnAg/Cu界面仍然结合牢固.Cu6Sn5/Cu平直界面中形成的孔洞对凸点的长期可靠性构成威胁.Experiments were carried out to investigate an area-array SnAg alloy electroplating solder bumping process with a bump size of less than 100μm. Sn-3.0Ag solder bumps with smooth and shiny surfaces,uniform distribution of Ag atoms, the height uniformity within the chip,and over φ100mm wafer about 2.03% and 5.12% were fabricated. The intermetallic compound and microvoids at the SnAg/Cu interface as a function of the reflow times and their effects on the bonding reliability of solder bumps were studied. The scalloped Cu6 Sn5 phase grew by a ripening process during multi-reflow. Volume shrinkage during phase transformation was believed to be the main reason for the formation of voids.＇The average shear strength of solder bumps increased as the reflow time increased. The combination of SnAg on TiW/Cu UBM was reliable under multi-reflow. Voids showed no significant impacts on the solder bonds in this study. Voids at the layered Cu6 Sn5/Cu interface would be a threat to the reliability of solder bumps.

关 键 词：SNAG 凸点 金属间化合物 孔洞 可靠性 多次回流 

分 类 号：TN405[电子电信—微电子学与固体电子学]