Interfacial microstructure evolution and shear behavior of Au–20Sn/(Sn)Cu solder joints bonded at 250 °C

Liu, Wensheng; Wang, Yikai; Ma, Yunzhu; Yu, Qiang; Huang, Yufeng

doi:10.1016/j.msea.2015.11.025

Cited by 31 publications

(5 citation statements)

References 27 publications

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“…The current research, involving Cu-Au80Sn20 joining, mainly focuses on the effect of aging on the microstructure and properties of the solder under service conditions. Wensheng Liu [10] investigated the interfacial microstructure evolution and shear behavior of Au-20Sn/(Sn)Cu solder joints after isothermal aging. The results showed that the AuSn 2 and (Cu,Au) 6 Sn 5 layers formed at the interface gradually disappeared and the interface configuration transformed from AuSn/AuSn 2 /(Cu,Au) 6 Sn 5 /Cu 3 Sn layers to AuSn/Cu 3 Sn layers.…”

Section: Introductionmentioning

confidence: 99%

Microstructure Evolution and Shear Strength of the Cu/Au80Sn20/Cu Solder Joints with Multiple Reflow Temperatures

et al. 2022

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In order to present the multiple reflow process during electronic packaging, the influence of the different short-time reheating temperatures on the microstructure and shear strength of the Cu/Au80Sn20/Cu solder joints was studied and discussed. The results showed that high-quality Cu/Au80Sn20/Cu solder joints were obtained with 30 °C for 3 min. The joints were mainly composed of the ζ-(Au,Cu)5Sn intermetallic compound (IMC) with an average thickness of 8 μm between Cu and solder matrix, and (ζ-(Au,Cu)5Sn +δ-(Au,Cu)Sn) eutectic structure in the solder matrix. With an increase in the multiple reflow temperature from 180 °C to 250 °C, the microstructure of the joint interface showed little change due to the barrier effect of the formed ζ IMC layer and the limitation of short-time reheating on the element diffusion. The eutectic structures in the solder matrix were coarsened and transformed from lamellar to the bulk morphology. The shear strength of the as-welded joint reached 31.5 MPa. The joint shear strength decreased slightly with reheating temperatures lower than 200 °C, while it decreased significantly (by about 10%) with reheating temperatures above 250 °C compared to the as-welded joint. The shear strength of the joints was determined by the brittle solder matrix, showing that the joint strength decreased with the coarsening of the δ phase in the eutectic structure.

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Section: Introductionmentioning

confidence: 99%

Microstructure Evolution and Shear Strength of the Cu/Au80Sn20/Cu Solder Joints with Multiple Reflow Temperatures

et al. 2022

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“…The other two layers have a more complex microstructure with many nanoscale IMCs. Liu et al 38) found the AuSn/AuSn 2 /AuSn 4 /Sn/ (Cu,Au) 6 Sn 5 /Cu 3 Sn layer at the interface of the Au20Sn solder and (Sn)Cu substrate during reflow at 250°C, and the AuSn 4 IMC layer gradually disappeared as the reflow time increased. The AuSn 2 and (Cu,Au) 6 Sn 5 IMC at the solder joint gradually disappeared and the interfacial structure was transformed into AuSn/Cu 3 Sn after isothermal aging treatment.…”

Section: Interfacial Reactionsmentioning

confidence: 99%

“…Their fracture surfaces shifted from the Sn/(Cu,Au) 6 Sn 5 layer to the AuSn 4 /(Cu,Au) 6 Sn 5 layer and eventually to the AuSn 2 /(Cu,Au) 6 Sn 5 layer. 38) The shear strength of the solder joint reduces continuously and the fracture surface shifts from the AuSn 2 /(Cu,Au) 6 Sn 5 layer to the AuSn layer and eventually to the Cu 3 Sn/Cu interface as the aging time increases. With the increase of aging time, the shear strength of solder joints reduces, and the fracture surface gradually shifts from the (Au,Cu) 5 Sn/Cu layer to the Au20Sn solder matrix.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Structure and Properties of Au–Sn Lead-Free Solders in Electronic Packaging

Wang

Zhang

2022

Mater. Trans.

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The requirements for electronic devices in high-temperature environment such as avionics and automotive have promoted the development of high-temperature solders. The Au20Sn solder, which is one of the hot topics of the current research in the field of electronic packaging, is widely used in flip-chip, light-emitting diode and hermetic package fields because of its good creep resistance, corrosion resistance and flux-free soldering. Recent research about the microstructure, wettability, interfacial intermetallic compounds, and mechanical properties of Au20Sn solder were reviewed. This paper focuses on the interfacial reaction of Au20Sn with different substrates and the mechanical properties of Au20Sn solder joints. In addition, the current research shortages of Au20Sn solders and the development directions are presented.

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“…The reliability of the solder joint depends on the nature of the solder itself but is also closely related to the intermetallic compounds (IMCs) formed in the interfacial reaction [9]. The experimental results demonstrate that IMCs are mainly composed of AuCu and (Au,Cu) 5 Sn on the Au80Sn20/Cu interface [10][11][12][13][14][15]. However, these types of IMCs greatly affect the long-term reliability of the solder joints attributed to their intrinsic brittleness.…”

Section: Introductionmentioning

confidence: 99%

“…Liu et al [13] found that the shear strength of solder joints was 67.5 MPa in the presence of only (Au,Cu) 5 Sn phase at the interface, and then Huang et al [15] found that the strength of solder joints increased to 90 MPa when a nano-AuCu layer was formed at the interface. Liu et al [13] studied the fracture behavior of solder joints, and the results showed that the fracture mainly occurred at the (Au,Cu) 5 Sn/Cu interface. Later, Huang et al [15] also explored the influence of the nano-AuCu layer on the fracture behavior.…”

Section: Introductionmentioning

confidence: 99%

The Stability and Electronic Structure of Cu(200)/AuCu(200) Interface: An Insight from First-Principle Calculation

Feng

et al. 2022

Materials

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AuCu phase had a significant effect on the bonding strength of Au80Sn20 alloy and Cu substrate. The formation of the AuCu(200)/Cu(200) interface significantly improves the shear strength of solder joints. Therefore, it is particularly important to analyze the strengthening mechanism of the AuCu phase in the Cu matrix. The atomic structure, interfacial stability, and interfacial bonding properties of the Cu(200)/AuCu(200) interface were investigated using first-principle calculation. The layer spacing convergence results show that seven layers of Cu(200) surface and seven layers of AuCu(200) surface are enough thick to be chosen for the interface model. The calculation shows that the surface energies are 1.463 J/m2 and 1.081 J/m2 for AuCu(200) surface and Cu(200) surface, respectively. Four interface combinations of Top sit, Long bridge, Short bridge, and Hollow were investigated by considering four stacking methods of AuCu(200). It is shown that the interfacial configuration of the Long bridge is the most stable and favorable structure, which has the largest adhesion work, the smallest interfacial energy, and the smallest interfacial spacing. The density of states and electron difference density were calculated for the four interfacial configurations, and the results showed that the main bonding mode of the Long bridge interface is composed of both Cu-Cu covalent bonds and Au-Cu covalent bonds.

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Interfacial microstructure evolution and shear behavior of Au–20Sn/(Sn)Cu solder joints bonded at 250 °C

Cited by 31 publications

References 27 publications

Microstructure Evolution and Shear Strength of the Cu/Au80Sn20/Cu Solder Joints with Multiple Reflow Temperatures

Microstructure Evolution and Shear Strength of the Cu/Au80Sn20/Cu Solder Joints with Multiple Reflow Temperatures

Structure and Properties of Au–Sn Lead-Free Solders in Electronic Packaging

The Stability and Electronic Structure of Cu(200)/AuCu(200) Interface: An Insight from First-Principle Calculation

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