3D电子封装锡晶须建模与实验验证

doi:10.16183/j.cnki.jsjtu.2021.017

摘要/Abstract

摘要：

压应力释放和原子扩散对3D电子封装中晶须的生长具有重要影响,压应力也是动态再结晶(DRX)的主要因素之一.利用基于有限元的锡晶须生长机理和行为的数学模型,仿真研究具有典型物理尺寸和结构形状的3D电子封装锡层在硅衬底上形成晶须的过程,实现对晶须的定性分析和生长趋势推演;通过控制实验背景氩气体压力、热循环温度和循环周期等关键参数,构建外部因素和镀层薄膜中内压应力与晶须生长速度、长度和密度的加速试验系统;利用扫描电子显微镜观察和检测晶须生长速度和密度变化,并与仿真结果对比,验证压应力释放、原子扩散和DRX在3D电子封装锡晶须生长数学模型中的有效性,实现对晶须的定量描述,对减少未来3D封装微结构图形设计中的晶须问题提供建设性建议.

关键词: 压应力, 原子扩散, 锡晶须, 3D电子封装, 数学模型, 加速试验

Abstract:

The release of compressive stress and atom diffusion have important influences on the growth of whiskers in 3D electronic packaging, and the compressive stress is also one of the main factors for dynamic recrystallization (DRX). By using the mathematical model of growth mechanism and the behavior of tin whisker based on the finite element method, the process of forming whiskers on silicon substrate by 3D electronic packaging tin layer with a typical physical size and structure was simulated. The qualitative analysis and growth of whiskers were realized. By controlling the key parameters such as gas pressure, thermal cycling temperature, and cycle of Ar in the background of the experiment, the external factors and plating process were constructed. The experimental system of accelerated test of internal pressure stress and whisker growth speed, length, and density in the film was constructed. The growth rate and density of whiskers were observed and detected by SEM. The effectiveness of the mathematical model of stress release, atom diffusion, and DRX in 3D electronic packaging tin whiskers was verified by SEM. The quantitative description of whiskers was realized, providing constructive suggestions for reducing whisker problems in future 3D packaging microstructure graphic design.

Key words: compressive stress, atomic diffusion, tin whisker, 3D electronic packaging, mathematical model, accelerated test

中图分类号:

TB383

王泽坤, 张福曦. 3D电子封装锡晶须建模与实验验证[J]. 上海交通大学学报, 2021, 55(11): 1445-1452.

WANG Zekun, ZHANG Fuxi. Modeling and Experimental Study of Tin Whiskers for 3D Electronic Packaging[J]. Journal of Shanghai Jiao Tong University, 2021, 55(11): 1445-1452.

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形状	r₁/μm	L₁/μm	L₂/μm	俯视图表面积/μm²
平面	25.0	157.0	0	1963.00
栅格	25.0	100.0	100.00	2500.00
角部	5.0	20.0	20.00	100.00
孔#1	5.0	20.0	10.00	75.00
孔#2	1.4	3.2	5.59	3.92

形状	r₁/μm	L₁/μm	L₂/μm	S/μm²	P
平面	10	62.8 (100%)	0	314	0.200
栅格	10	31.4 (50%)	31.4 (50%)	200	0.157
角部	10	31.4 (50%)	31.4 (50%)	200	0.157
孔#1	10	41.9 (66%)	20.9 (33%)	300	0.140
孔#2	10	22.6 (36%)	40.2 (64%)	200	0.113