Simulation for Cu Atom Diffusion Leading to Fluctuations in Solder Properties and Cu6Sn5 Growth during Multiple Reflows

Min Shang,Haoran Ma,Yunpeng Wang,Chong Dong,Haitao Ma

doi:10.3390/met11122041

Min Shang, Haoran Ma + Show 3 more

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https://doi.org/10.3390/met11122041

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Journal: Metals	Publication Date: Dec 16, 2021
Citations: 1	License type: CC BY 4.0

Affiliation: Dalian University of Technology, Dalian University

Abstract

The multiple reflows process is widely used in 3D packaging in the field of electronic packaging. The growth behavior of interfacial intermetallic compound (IMC) is more important to the reliability of solder joints. In this paper, experimental measurement combined with simulation calculation were preformed to investigate the evolution of Cu concentration in solders during multiple reflows, as well as its effects on the growth behavior of IMC and solder properties. The concentration of Cu in solder fluctuated, increasing with the increase of reflow times, which led to the fluctuation in the growth rate of the IMC. Furthermore, the Vickers hardness and melting point of the solder fluctuated during the multiple reflow processes due to the fluctuation in the Cu concentration. The data generated during this study could help to develop machine learning tools in relation to the study of interfacial microstructure evolution during multiple reflows.

Highlights

IntroductionMultiple reflow is an inevitable and commonly used packaging process in 3D electronic packaging technology, spawned by the trend towards the miniaturization of electronic products [6,7]
This paper explores the variation in Cu concentrations during multiple reflows and its effect on the growth behavior of intermetallic compound (IMC) and the properties of solder through a combination of experiments and simulations
An experimental measurement was combined with a simulation calculasummary,the an evolution experimental measurement was combined a simulation calcution toIninvestigate of the

Summary

Introduction

Multiple reflow is an inevitable and commonly used packaging process in 3D electronic packaging technology, spawned by the trend towards the miniaturization of electronic products [6,7] One example of this is the soldering processes of the “Double-POSSUMTM” 3D packaging structure developed by Amkor, the A9 application processor fabricated by Apple or the AMD’s graph card made by Hynix [8,9,10]. In this package, the three daughter chips are first interconnected with the larger mother chip in the form of a flip-chip to form the device, before being interconnected with the largest mother chip, connected to the package substrate and, interconnected with the PCB substrate to complete the package. In order to produce high integration and microminiaturization, all 3D electronic packaging products need to interconnect in the vertical direction [11] the through multi-reflow process, in which the overgrowth of brittle interfacial intermetallic compound (IMC) tends to occur, further resulting in service reliability problems for electronic devices [12,13,14]

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