倒装焊中复合SnPb焊点形态模拟  

Simulation of Duplex Solder Joints Geometry in Flip Chip Technology

作　　者：朱奇农[1] 王国忠[1] 罗乐[1] 

机构地区：[1]中科院上海冶金研究所,上海200050

出　　处：《电子学报》2000年第5期55-58,共4页Acta Electronica Sinica

摘　　要：本文给出了倒装焊 (flip chip)焊点形态的能量控制方程 ,采用SurfaceEvolver软件模拟了倒装焊复合SnPb焊点 (高Pb焊料凸点 ,共晶SnPb焊料焊点 )的三维形态 .利用焊点形态模拟的数据 ,分析了芯片和基板之间SnPb焊点的高度与焊点设计和焊接工艺参数的关系 .研究表明 :共晶SnPb焊料量存在临界值 ,当共晶SnPb焊料量小于临界值时 ,焊点的高度等于芯片上高Pb焊料凸点的半径值 ;当共晶SnPb焊料量大于临界值时 ,焊点的高度随共晶SnPb焊料量的增加而增加 .另外 ,采用无量纲的形式给出了焊点高度与共晶焊料量、焊盘尺寸、芯片凸点的尺寸 ,芯片重量之间的关系模型 ,研究结果对倒装焊焊点形态的控制、工艺参数的优化和提高焊点可靠性具有指导意义 .Energy controlling equation for solder joint geometry in flip chip technology was presented and three dimensiond duplex solder joints (with high Pb base solder bump and eutectic SnPb solder fillet) geometry was predicted by using surface evolver program.The relationship of the stand off height between chip and substrate vs.the design parmeters and process parameters of solder joints were investigated.It was found there existed a critical eutectic solder volume V critical .When the volume of eutectic solder was smaller than V critical ,the stand off height of solder joint was equal to the radius of solder bump on chip;when the volume is greater than V critical ,the stand off height was greater than the radius of solder bump and increased with the increase of eutectic solder volume,Besides,the regression model was presented for stand off height of solder joints vs.eutectic solder volume,substrate pad size,solder bump size and chip weight in dimensionless form.All the results could be used to control the solder joint geometry,optimize the process parameters and improve the reliability of solder joint in production.

关 键 词：倒装焊 焊点形态 SnPb 封装 

分 类 号：TN405.93[电子电信—微电子学与固体电子学]