Diffusion of elements during reflow ageing of Sn-Zn solder in liquid state on Ni/Cu substrate – theoretical and experimental study

Mittal, Jagjiwan; Lin, Kwang Lung

doi:10.1108/ssmt-10-2017-0035

Cited by 4 publications

(2 citation statements)

References 44 publications

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“…In the reflow process, the liquid reaction time lasts only a few minutes, but the IMC generated is extremely fast and can be generated in less than 10 s [16]. The inter-diffusion process between the solder and the substrate occurred at the reflow temperature is complicated [17]. Generally, the complex interface reactions between solder and substate could be roughly divided into the following three steps.…”

Section: Theoretical Analysis Of the Imc Formation Processmentioning

confidence: 99%

Effect of the reflow process on IMC growth for different devices and complex components

Cui¹,

Tian²,

Zhao³

et al. 2022

Smart Mater. Struct.

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Intermetallic compound (IMC), as an inevitable part between pad and solder, has a severe effect on the strength and reliability of microelectronic interconnection. Here, an investigation was carried out on IMC growth for different devices and complex components. The device-level experiments were conducted with five factors: peak temperature, time duration above solder liquidus temperature, the thickness of solder paste, surface finish types, and package types including BGA and QFP. Meanwhile, four complex components with the same reflow profile were conducted and compared for component-level experiments. A scanning electron microscopy was used to measure the thickness and determine the spatial distribution of the elements through the intermetallic compound. The multivariate analysis of the formation and growth of IMC during reflow soldering was studied based on Nernst-Shchukarev's equation and the results of the experiments. The difference in IMC thickness between BGA and QFP with different factors was discussed and compared separately. The results showed that the peak temperature and time above liquidus played a vital role in the IMC growth and the solder paste thickness and different pad metallization could not be ignored. SEM pictures of the solder and statistical results were revealed that the surface finish type has a marked impact on the formation of the IMC. For PCB with numbers of components, the IMC thickness and uniformity of solder joints at corner and center positions showed some regularity differences. Meanwhile, the bump shape (Cu1-xNix)6Sn5 IMC was observed for small size BGA with ENIG during the reflow process. The results have a significant meaning to optimize its reflow process parameters for complex components, to improve the interconnection reliability in engineering.

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Section: Theoretical Analysis Of the Imc Formation Processmentioning

confidence: 99%

Effect of the reflow process on IMC growth for different devices and complex components

Cui¹,

Tian²,

Zhao³

et al. 2022

Smart Mater. Struct.

View full text Add to dashboard Cite

show abstract

“…It is generally considered to add elements such as silver, copper, zinc and bismuth, respectively, to tin-based solders to form various lead-free alloy systems. For example, Sn-Zn (Mittal and Lin, 2018), Sn-Ag-Cu (Anderson, 2007), Sn-Cu (Zhu et al, 2006), Sn-Bi (Dong et al, 2008), etc., are tin-based lead-free solders of interest. The suitability of new lead-free solders has been explored by measuring properties such as wettability (Plevachuk et al, 2010;Ye et al, 2013), solderability (Park et al, 2000) and mechanical properties (Yang et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Prediction of viscosity of ternary tin-based lead-free solder melt using BP neural network

2020

SSMT

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Purpose Viscosity is an important basic physical property of liquid solders. However, because of the very complex nonlinear relationship between the viscosity of the liquid ternary Sn-based lead-free solder and its determinants, a theoretical model for the viscosity of the liquid Sn-based solder alloy has not been proposed. This paper aims to address the viscosity issues that must be considered when developing new lead-free solders. Design/methodology/approach A BP neural network model was established to predict the viscosity of the liquid alloy and the predicted values were compared with the corresponding experimental data in the literature data. At the same time, the BP neural network model is compared with the existing theoretical model. In addition, a mathematical model for estimating the melt viscosity of ternary tin-based lead-free solders was constructed using a polynomial fitting method. Findings A reasonable BP neural network model was established to predict the melt viscosity of ternary tin-based lead-free solders. The viscosity prediction of the BP neural network agrees well with the experimental results. Compared to the Seetharaman and the Moelwyn–Hughes models, the BP neural network model can predict the viscosity of liquid alloys without the need to calculate the relevant thermodynamic parameters. In addition, a simple equation for estimating the melt viscosity of a ternary tin-based lead-free solder has been proposed. Originality/value The study identified nine factors that affect the melt viscosity of ternary tin-based lead-free solders and used these factors as input parameters for BP neural network models. The BP neural network model is more convenient because it does not require the calculation of relevant thermodynamic parameters. In addition, a mathematical model for estimating the viscosity of a ternary Sn-based lead-free solder alloy has been proposed. The overall research shows that the BP neural network model can be well applied to the theoretical study of the viscosity of liquid solder alloys. Using a constructed BP neural network to predict the viscosity of a lead-free solder melt helps to study the liquid physical properties of lead-free solders that are widely used in electronic information.

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Effect of CNTs on the intermetallic compound growth between Sn solder and Cu substrate during aging and reflowing

Zhang

Jiang

2021

J Mater Sci: Mater Electron

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Diffusion of elements during reflow ageing of Sn-Zn solder in liquid state on Ni/Cu substrate – theoretical and experimental study

Cited by 4 publications

References 44 publications

Effect of the reflow process on IMC growth for different devices and complex components

Effect of the reflow process on IMC growth for different devices and complex components

Prediction of viscosity of ternary tin-based lead-free solder melt using BP neural network

Effect of CNTs on the intermetallic compound growth between Sn solder and Cu substrate during aging and reflowing

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