Purpose

This paper focuses on the reliability of the solder joint after the self-alignment phenomenon during reflow soldering. The aim of this study is to analyse the joint quality of the self-alignment assemblies of SnAg alloy solder joints with varying silver content.

Design/methodology/approach

The shear strength assessment was conducted in accordance with the JIS Z3 198-7 standard. The standard visual inspection of IPC-A-610G was also performed to inspect the self-alignment features of the solder joint samples. Statistical analysis was conducted to determine the probabilistic relationship of shear strength of the misalignment components.

Findings

The results from the mechanical reliability study indicate that there were decreasing trends in the shear strength value as misalignment offset increased. For shift mode configuration in the range of 0-300 µm, the resulting chip assembly inspection after the reflow process was in line with the IPC-A-610G standard. The statistical analysis shows that the solder type variation was insignificant to the shear strength of the chip resistor. The study concluded that the fracture occurred partially in the termination metallization at the lower part of the chip resistor. The copper content of the joint on that area shows that the crack occurred in the solder joint, and high silver content on the selected zone indicated that the fracture happened partially in the termination structure, as the termination structure of the lead-free chip resistor consists of an inner layer of silver and an outer layer of tin.

Practical implications

This study’s findings provide valuable guidelines and references to engineers and integrated circuit designers during the reflow soldering process in the microelectronics industry.

Originality/value

Studies on the effect of component misalignment on joint mechanical reliability are still limited, and studies on solder joint reliability involving the effect of differing contents of silver on varying chip component offset are rarely reported. Thus, this study is important to effectively bridge the research gap and yield appropriate guidelines in the potential industry.

中文翻译：

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回流焊接后自对准芯片组件的机械可靠性

目的

本文着重研究回流焊过程中自对准现象后焊点的可靠性。这项研究的目的是分析含银量不同的SnAg合金焊点自对准组件的接头质量。

设计/方法/方法

根据JIS Z3 198-7标准进行抗剪强度评估。还执行了IPC-A-610G的标准外观检查，以检查焊点样品的自对准特征。进行统计分析以确定未对准组件的剪切强度的概率关系。

发现

机械可靠性研究的结果表明，随着偏心偏移的增加，剪切强度值呈下降趋势。对于0-300 µm范围内的移位模式配置，回流工艺后进行的芯片组装检查符合IPC-A-610G标准。统计分析表明，焊料类型的变化与片式电阻器的剪切强度无关紧要。研究得出的结论是，断裂部分发生在片式电阻器下部的端接金属层中。该区域接头的铜含量表明在焊接接头中出现了裂纹，而选定区域中的高银含量表明该断裂部分发生在端接结构中，

实际影响

这项研究的发现为微电子行业的回流焊接过程中的工程师和集成电路设计师提供了有价值的指导和参考。

创意/价值

关于部件未对准对接合机械可靠性的影响的研究仍然是有限的，并且很少报道涉及不同银含量对变化的芯片部件偏移的影响的焊接接合可靠性的研究。因此，这项研究对于有效弥合研究差距并为潜在行业提供适当的指导方针非常重要。