Critical Review of Size Effects on Microstructure and Mechanical Properties of Solder Joints for Electronic Packaging

Shaobin Wang,Yao Yao,Xu Long

doi:10.3390/app9020227

Shaobin Wang, Yao Yao + Show 1 more

Open Access

https://doi.org/10.3390/app9020227

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Journal: Applied Sciences	Publication Date: Jan 10, 2019
Citations: 22	License type: CC BY 4.0

Affiliation: Northwestern Polytechnical University

Abstract

With the miniaturization of electronic packaging and devices, the size of solder joints in electronics is also decreasing from bulk solder joints to micro-bumps. Both the microstructure and mechanical properties of the solder joints are also evolving with the decreasing size, which brings great concern for the reliability of different sizes of solder interconnections. In this paper, the effect of solder size on the microstructure (i.e., interfacial intermetallic compound (IMC) growth, precipitation in the solder matrix, dendrite arms, and undercooling) and mechanical properties (i.e., tensile property, shear and compression strength, fracture toughness, and creep deformation) are reviewed from the mechanical point of view. In addition, some areas for further researches about size effects on solder joints are discussed.

Highlights

With the rapid updating of electronic packaging and devices, micro-bumps are becoming widely used in 3D packaging [1,2,3]
Volume and size effects on microscale solder joints were reviewed by Yin et al [9] in 2011
The size effects on solder joints of electronic devices is a complicated topic which covers the microstructure evolution and the mechanical behavior, each of which was separately discussed in the existing literature

Summary

Introduction

With the rapid updating of electronic packaging and devices, micro-bumps are becoming widely used in 3D packaging [1,2,3]. The size effects on solder joints of electronic devices is a complicated topic which covers the microstructure evolution (such as the formation of multiple kinds of intermetallic compounds) and the mechanical behavior (such as shear, creep, and fracture behaviors), each of which was separately discussed in the existing literature. Line-type and lap-shear solder joints are usually used to test the tensile and shear properties, respectively. Wedge indenters are6Sn used in the microcantilever fracture test, while flat-end milling and nanoindentation.

IMC Formation and Growth

Solidification and Recrystallization in the Solder Matrix

Size Effects on Mechanical Properties of Solder Joints

Tensile Behavior of Solder Joint

Fracture and Creep Deformation of Solder Joints