摘要
针对球栅阵列(BGA)焊点微米级缺陷在传统检测方法(如X射线、单一热成像)中存在的区分度不足、依赖经验阈值等问题,提出一种基于多物理场仿真的电-热耦合瞬态分析方法。构建包含芯片、焊球及印刷电路板(PCB)的精细化三维有限元模型,通过引入差异化接触电阻参数,物理表征虚焊点的高阻特性与桥连点的电流旁路效应。在周期性交变电流激励下,揭示不同缺陷类型在动态工作条件下的电热响应机制。基于此,提出结合局部电位异常与温度梯度特征的联合检测判据,有效区分虚焊导致的局部热点聚集与桥连引发的快速热扩散现象。研究结果表明:该方法可实现对微米级BGA焊点缺陷的量化识别,克服传统检测技术在细微缺陷辨识方面的局限,为高密度封装可靠性评估提供一种有效的无损检测手段。
Conventional detection methods for ball grid array(BGA)solder joints,such as X-ray or single-mode thermal imaging,often struggle to achieve precise identification and quantitative assessment when confronted with micron-level defects,due to insufficient differentiation and reliance on empirical thresholds.To address this challenge,this study developed a multiphysics simulation model based on COMSOL Multiphysics®.This model accurately represented the three-dimensional structure encompassing the chip,solder balls,and printed circuit board(PCB),and established a transient electrical-thermal coupling analysis framework.By incorporating differentiated contact resistance parameters to physically characterize the high-resistance of cold solder joints and the currentbypassing effect of solder bridging,and by applying a periodic alternating current for excitation,the study effectively revealed the unique response mechanisms of these defects under dynamic operating conditions.Based on these findings,a joint detection criterion combining localized electrical potential anomalies and temperature gradient features was proposed.This criterion effectively distinguished the localized hot-spot concentration associated with cold solder joints from the rapid thermal diffusion caused by solder bridging,thereby overcoming the insufficient differentiation capability of traditional methods for subtle defects.The study provides a quantitative non-destructive testing method for BGA solder joint defects,which is of significant importance for enhancing the reliability assessment of high-density packaging.
作者
王哲
沙林秀
WANG Zhe;SHA Linxiu(School of Electronic Engineering,Xi'an Shiyou University,Xi'an 710065,Shaanxi,China)
