Numerical investigation of thermal fatigue crack growth behavior in SAC305 BGA solder joints

IF 1.7 4区材料科学 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Soldering & Surface Mount Technology Pub Date : 2024-01-01 DOI:10.1108/ssmt-08-2023-0049

Rilwan Kayode Apalowo, Mohamad Aizat Abas, Muhamed Abdul Fatah Muhamed Mukhtar, Fakhrozi Che Ani, Mohamad Riduwan Ramli

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引用次数: 0

Abstract

Purpose

This study aims to investigate the reliability issues of microvoid cracks in solder joint packages exposed to thermal cycling fatigue.

Design/methodology/approach

The specimens are subjected to JEDEC preconditioning level 1 (85 °C/85%RH/168 h) with five times reflow at 270°C. This is followed by thermal cycling from 0°C to 100°C, per IPC-7351B standards. The specimens' cross-sections are inspected for crack growth and propagation under backscattered scanning electronic microscopy. The decoupled thermomechanical simulation technique is applied to investigate the thermal fatigue behavior. The impacts of crack length on the stress and fatigue behavior of the package are investigated.

Findings

Cracks are initiated from the ball grid array corner of the solder joint, propagating through the transverse section of the solder ball. The crack growth increases continuously up to 0.25-mm crack length, then slows down afterward. The J-integral and stress intensity factor (SIF) values at the crack tip decrease with increased crack length. Before 0.15-mm crack length, J-integral and SIF reduce slightly with crack length and are comparatively higher, resulting in a rapid increase in crack mouth opening displacement (CMOD). Beyond 0.25-mm crack length, the values significantly decline, that there is not much possibility of crack growth, resulting in a negligible change in CMOD value. This explains the crack growth arrest obtained after 0.25-mm crack length.

Practical implications

This work's contribution is expected to reduce the additional manufacturing cost and lead time incurred in investigating reliability issues in solder joints.

Originality/value

The work investigates crack propagation mechanisms of microvoid cracks in solder joints exposed to moisture and thermal fatigue, which is still limited in the literature. The parametric variation of the crack length on stress and fatigue characteristics of solder joints, which has never been conducted, is also studied.

查看原文本刊更多论文

SAC305 BGA 焊点热疲劳裂纹生长行为的数值研究

设计/方法/途径试样经过 JEDEC 1 级预处理（85°C/85%RH/168 h），在 270°C 下回流五次。然后按照 IPC-7351B 标准从 0°C 到 100°C 进行热循环。在背散射扫描电子显微镜下对试样的横截面进行裂纹生长和扩展检查。解耦热力学模拟技术用于研究热疲劳行为。研究结果裂纹从焊点的球栅阵列角开始，通过焊球的横向部分传播。裂纹增长持续增加，直至裂纹长度达到 0.25 毫米，然后放缓。裂纹顶端的 J 积分和应力强度因子 (SIF) 值随着裂纹长度的增加而减小。在裂纹长度为 0.15 毫米之前，J 积分和 SIF 随裂纹长度的增加而略有降低，并且相对较高，导致裂纹口张开位移（CMOD）迅速增加。当裂纹长度超过 0.25 毫米时，其值明显下降，裂纹增长的可能性不大，因此 CMOD 值的变化可以忽略不计。这就解释了在 0.25 毫米裂纹长度之后获得的裂纹增长捕捉值。原创性/价值这项工作研究了暴露在潮湿和热疲劳环境下的焊点中微空洞裂纹的裂纹扩展机制，而这在文献中还很有限。此外，还研究了裂纹长度对焊点应力和疲劳特性的参数变化，而这一研究从未进行过。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Soldering & Surface Mount Technology 工程技术-材料科学：综合

CiteScore

4.10

自引率

15.00%

发文量

审稿时长

>12 weeks

期刊介绍： Soldering & Surface Mount Technology seeks to make an important contribution to the advancement of research and application within the technical body of knowledge and expertise in this vital area. Soldering & Surface Mount Technology compliments its sister publications; Circuit World and Microelectronics International. The journal covers all aspects of SMT from alloys, pastes and fluxes, to reliability and environmental effects, and is currently providing an important dissemination route for new knowledge on lead-free solders and processes. The journal comprises a multidisciplinary study of the key materials and technologies used to assemble state of the art functional electronic devices. The key focus is on assembling devices and interconnecting components via soldering, whilst also embracing a broad range of related approaches.