倒装叠层金钉头凸点键合成型仿真及可靠性研究

发布时间：2018-01-10 03:12

本文关键词：倒装叠层金钉头凸点键合成型仿真及可靠性研究　出处：《桂林电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：倒装芯片技术是芯片互连主要方式之一。本文通过有限元仿真以及实验验证的方法,对倒装芯片叠层金钉头凸点键合成型及其应力应变进行了分析:倒装叠层第一层金钉头凸点应力应变水平分布较高的区域集中在以焊盘几何中心的同心圆周边区域,金钉头凸点将优先在这个区域内与焊盘形成键合;倒装芯片叠层金钉头凸点高度随着键合压力、键合功率以及键合时间的增大而减少,第一层金钉头凸点直径和第二层金钉头凸点直径随着键合压力、键合功率以及键合时间的增大而增大;倒装叠层金钉头键合过程中,劈刀对第一层金钉头凸点关键尺寸的影响少于对第二层金钉头凸点的影响;进行第二层金钉头凸点的键合时,为了保证第一层金钉头凸点不会因为第二层金钉头凸点的键合出现失效,需要保证键合压力以及键合功率在一定的范围之内。基于正交试验设计,设计了键合工艺参数不同水平组合倒装叠层金钉头热循环加载仿真凸点应力应变分析,结果表明:倒装叠层金钉头凸点热循环应力应变分布是不均匀的,应力应变最大值出现在凸点与焊盘键合处;倒装叠层金钉头凸点热循环加载条件下关键时刻点最大应力应变值极差方和方差分析表明:热循环加载条件下,键合参数对倒装叠层金钉头凸点应力应变影响由大到小排序为:键合压力键合功率键合时间;其中键合压力对倒装叠层金钉头凸点应力应变影响为显著,其它两个键合工艺参数不显著;倒装叠层金钉头凸点最优键合工艺参数水平组合为:键合压力为64gf、键合功率为0.15w以及键合时间为34ms。对热压超声焊机制作的倒装叠层金钉头凸点样件进行了100天共计2400小时的热循环加载可靠性实验,金钉头凸点失效数据极差和方差分析表明:热循环加载条件下,各键合工艺参数对倒装叠层金钉头凸点可靠性影响按大小排序为:键合压力键合功率键合时间;热循环加载条件下,对倒装叠层金钉头凸点可靠性影响显著的键合工艺参数是键合压力,其它两个键合工艺参数为不显著;倒装叠层金钉头凸点最优键合工艺参数水平组合为:键合压力64gf、键合功率0.15w以及键合时间34ms;利用Weibull分布对倒装叠层金钉头凸点热循环加载失效数据分析表明:倒装叠层金钉头凸点热循环加载失效Weibull分布的尺度参数?和形状参数?分别为515.1522和5.032403;其期望寿命(平均寿命)E(t)为474.3985小时,中位寿命0.5t为478.967小时,特征寿命0.368t为515.1186小时。
[Abstract]:Flip chip technology is one of the main methods of chip interconnection. In this paper, the synthetic type and stress strain of the convex dot bond of the stacked gold nail head on the flip chip are analyzed. The area with high horizontal distribution of stress and strain at the convex point of the first layer gold nail head in the inverted layer is concentrated in the concentric circumference of the center of the weld pad geometry. The protruding spot of the gold nail head will preferentially bond with the pad in this area; With the increase of bonding pressure, bonding power and bonding time, the height of the convex point of the first layer gold nail head and the second layer gold nail head convex point diameter decrease with the increase of bonding pressure, the diameter of the first layer gold nail head convex point and the second layer gold nail head convex point diameter increase with the bonding pressure. The bonding power and the bonding time increase; During the bonding process, the effect of the splitter on the key size of the protruding point of the first layer gold nail head is less than that on the second layer gold nail head convex point. In order to ensure that the first layer gold nail head convex point bond does not occur because of the second layer gold nail head convex point bonding failure. It is necessary to ensure that the bonding pressure and bonding power are within a certain range. Based on the orthogonal experimental design, the stress and strain analysis of hot cycle loading simulation of different horizontal combination of stacked gold nail head is designed. The results show that the distribution of stress and strain is not uniform and the maximum value of stress and strain appears at the joint between the convex spot and the pad. The maximum stress-strain value of critical point under thermal cyclic loading condition and variance analysis show that: under the condition of thermal cyclic loading. The influence of bonding parameters on the stress and strain of the convex point of the inverted stacked gold nail head is arranged from large to small as follows: bonding pressure bonding power bonding time; The bonding pressure has a significant effect on the stress and strain of the convex point of the inverted stacked gold nail head, while the other two bonding process parameters are not significant. The optimal bonding process parameters are as follows: bonding pressure is 64gf. The bonding power is 0.15w and the bonding time is 34ms.The reliability experiment of the hot pressing ultrasonic welding machine is carried out for 100 days and 2400 hours. The range difference and variance analysis show that under the condition of thermal cyclic loading, the effect of each bonding process parameter on the reliability of the inverted stacked gold nail convex point is ranked as follows: bonding pressure bonding power bonding time; Under the condition of thermal cycling loading, the bonding pressure is the bonding pressure, but the other two process parameters are not significant. The optimal bonding process parameters are as follows: bonding pressure 64gf, bonding power 0.15w and bonding time 34ms; The Weibull distribution is used to analyze the failure data of thermal cyclic loading on the convex point of the inverted stacked gold nail head. It is shown that the scale parameters of the Weibull distribution of the thermal cyclic loading failure of the inverted stacked gold nail head are obtained. And shape parameters? 515.1522 and 5.032403, respectively; The average life expectancy (average life span) is 474.3985 hours, the median life span is 478.967 hours, and the characteristic life span is 0.368t is 515.1186 hours.
【学位授予单位】：桂林电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN405

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