scholarly journals Effects of Isothermal Aging on Interfacial Microstructure and Shear Properties of Sn-4.5Sb-3.5Bi-0.1Ag Soldering with ENIG and ENEPIG Substrates

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2027
Author(s):  
Zhimin Liang ◽  
Fei Shen ◽  
Zongyuan Yang ◽  
Da Xu ◽  
Shaowei Wei ◽  
...  
Keyword(s):  
Aging Time ◽  
Solder Joints ◽  
Solder Matrix ◽  
Interfacial Microstructure ◽  
Shear Tests ◽  
Thermal Reliability ◽  
Shear Properties ◽  
Electronic Products ◽  
Before And After ◽  
Interfacial Intermetallic Compounds

Sn–Sb system solders and ENIG/ENEPIG surface finish layers are commonly used in electronic products. To illustrate the thermal reliability evaluation of such solder joints, we studied the interfacial microstructure and shear properties of Sn-4.5Sb-3.5Bi-0.1Ag/ENIG and Sn-4.5Sb-3.5Bi-0.1Ag/ENEPIG solder joints after aging at 150 °C for 250, 500 and 1000 h. The results show that the intermetallic compound of Sn-4.5Sb-3.5Bi-0.1Ag/ENIG interface was more continuous and uniform compared with that of Sn-4.5Sb-3.5Bi-0.1Ag/ENEPIG interface after reflow. The thickness of the interfacial intermetallic compounds of the former was significantly thinner than that of the latter before and after aging. With extension of aging time, the former interface was stable, while obvious voids appeared at the interface of the latter after 500 h aging and significant fracture occurred after 1000 h aging. The shear tests proved that shear strength of solder joints decreased with increasing aging time. For the Sn-4.5Sb-3.5Bi-0.1Ag/ENEPIG joint after 1000 h aging, the fracture mode is ductile-brittle mixed type, which means fracture could occur at the solder matrix or the solder/IMC interface. For other samples of these two types of joints, ductile fracture occurred inside of the solder. The Sn-4.5Sb-3.5Bi-0.1Ag/ENIG solder joint was thermally more reliable than Sn-4.5Sb-3.5Bi-0.1Ag/ENEPIG.

scholarly journals Effects of Trace Oxygen Content on Microstructure and Performances of Au-20Sn/Cu Solder Joints

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 601
Author(s):  
Yang Li ◽  
Di Wu ◽  
Yabin Zhang ◽  
Liujue Wang ◽  
Songbai Xue
Keyword(s):  
Oxygen Content ◽  
Solder Joints ◽  
Interfacial Microstructure ◽  
High Oxygen Content ◽  
Continuous Increase ◽  
Electronic Products ◽  
Optical Window ◽  
Key Factor ◽  
Gas Tightness

The Au-20Sn solder is widely used in the packaging of high-end electronic products, and the requirement on the reliability of the solder joints is more and more strict with a continuous increase in the performance of the package products. As the oxygen content in the Au-Sn solder is a key factor dominating the quality of fluxless packaging, in this study, the wettability and spreading performance of the Au-20Sn solder with different oxygen contents and the interfacial microstructure, mechanical properties, gas tightness and ratio of soldering area of the Au-Sn/Cu solder joints prepared using these solders were comprehensively investigated to clarify the effects of trace oxygen content. The results reveal that the wetting and spreading performances of the solder decrease sharply with increasing oxygen conte[nt. When the oxygen content increased from 18 to 77 ppm, the spreading area of the solder on the Cu substrate decreased from 92.8 to 49.2 mm2, reducing by 47%. Meanwhile, pores and microcracks appear in the solder joint with relatively high oxygen content, making the shear strength decrease from 56.6 to 31.7 MPa. The oxygen also greatly affects the gas tightness and ratio of soldering area. For the optical window packaged using Au-Sn solder containing 40 ppm of oxygen, the leakage rate was higher than 5 × 10−11 mbar·m−3·s−1 and cannot fulfill the requirements. With increasing oxygen content in the Au-Sn solder, the cleanliness of the chip packaged with these solders deteriorated, and the solder surface was obviously oxidized. When the oxygen content was 18 ppm, the ratio of soldering area was 92%, but decreased sharply to 53% when the oxygen content increased to 77 ppm. It is demonstrated that an oxygen content lower than 27 ppm is required for the Au-20Sn solder used in fluxless packaging.

scholarly journals Microstructure and shear properties of ultrasonic-assisted Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints under thermal cycling

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jianguo Cui ◽  
Keke Zhang ◽  
Di Zhao ◽  
Yibo Pan
Keyword(s):  
Shear Strength ◽  
Thermal Cycling ◽  
Solder Joints ◽  
High Reliability ◽  
Sharp Decrease ◽  
Thermal Shock Test ◽  
Shear Properties ◽  
Equivalent Time ◽  
Ultrasonic Assisted ◽  
Reliability Of Solder Joints

AbstractThrough ultrasonic wave assisted Sn2.5Ag0.7Cu0.1RExNi/Cu (x = 0, 0.05, 0.1) soldering test and − 40 to 125 °C thermal shock test, the microstructure and shear properties of Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints under thermal cycling were studied by the SEM, EDS and XRD. The results show that the Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints with high quality and high reliability can be obtained by ultrasonic assistance. When the ultrasonic vibration power is 88 W, the ultrasonic-assisted Sn2.5Ag0.7Cu0.1RE0.05Ni/Cu solder joints exhibits the optimized performance. During the thermal cycling process, the shear strength of ultrasonic-assisted Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints had a linear relationship with the thickness of interfacial intermetallic compound (IMC). Under the thermal cycling, the interfacial IMC layer of ultrasonic-assisted Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints consisted of (Cu,Ni)6Sn5 and Cu3Sn. The thickness of interfacial IMC of ultrasonic-assisted Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints was linearly related to the square root of equivalent time. The growth of interfacial IMC of ultrasonic-assisted Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints had an incubation period, and the growth of IMC was slow within 300 cycles. And after 300 cycles, the IMC grew rapidly, the granular IMC began to merge, and the thickness and roughness of IMC increased obviously, which led to a sharp decrease in the shear strength of the solder joints. The 0.05 wt% Ni could inhibit the excessive growth of IMC, improve the shear strength of solder joints and improve the reliability of solder joints. The fracture mechanism of ultrasonic-assisted Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints changed from the ductile–brittle mixed fracture in the solder/IMC transition zone to the brittle fracture in the interfacial IMC.

Effects of Current Stressing on Shear Properties of Sn-3.8Ag-0.7Cu Solder Joints

2010 ◽  
Vol 26 (8) ◽  
pp. 737-742 ◽  
Author(s):  
X.J. Wang ◽  
Q.L. Zeng ◽  
Q.S. Zhu ◽  
Z.G. Wang ◽  
J.K. Shang
Keyword(s):  
Solder Joints ◽  
Shear Properties ◽  
Current Stressing

Flexural, in-plane shear and nail shear properties of falcataria-rubberwood laminated veneer board for flooring

Holzforschung ◽  
2008 ◽  
Vol 62 (6) ◽  
Author(s):  
Kweonhwan Hwang ◽  
EeDing Wong ◽  
Kohei Komatsu
Keyword(s):  
Radiata Pine ◽  
Strength Properties ◽  
Larix Leptolepis ◽  
Structural Components ◽  
Shear Tests ◽  
Plane Shear ◽  
Paraserianthes Falcataria ◽  
Shear Properties ◽  
Laminated Veneer Lumber ◽  
Good Potential

Abstract A research project has been conducted to develop structural laminated veneer lumber products from tropical wood, and to evaluate their feasibility for the structural components of wooden houses. As part of this project, we investigated the flexural, in-plane shear, and nail shear properties of laminated veneer board (LVB) manufactured from a combination of falcataria (Paraserianthes falcataria) and rubberwood (Hevea brasiliensis) for flooring applications. In addition, 11-ply larch (Larix leptolepis) and 7-ply radiata pine (Pinus radiata) plywood were investigated as controls. Larch plywood, bonded with phenol-based adhesive, showed the best strength properties in bending and shear tests, whereas the 12-ply (28 mm thick) resorcinol-based resin-bonded LVB had the highest ductility in nail shear. The LVB also had better bending and shear properties than radiata pine plywood. In conclusion, falcataria-rubberwood LVB demonstrated good potential to substitute larch plywood and radiata pine plywood in flooring applications.

Microstructure evolution and microimpact performance of Sn–Ag–Cu solder joints under thermal cycle test

2010 ◽  
Vol 25 (7) ◽  
pp. 1312-1320 ◽  
Author(s):  
Y.L. Huang ◽  
K.L. Lin ◽  
D.S. Liu
Keyword(s):  
Fracture Energy ◽  
Microstructure Evolution ◽  
Thermal Cycle ◽  
Fracture Behavior ◽  
Solder Ball ◽  
Solder Joints ◽  
Whisker Formation ◽  
Structural Variations ◽  
Before And After ◽  
Ball Joints

The microstructure and microimpact performance of Sn1Ag0.1Cu0.02Ni0.05In (SAC101NiIn)/AuNi/Cu solder ball joints were investigated after a thermal cycle test (TCT). The joints show complete bulk fracture behavior before TCT. Moreover, TCT facilitated interfacial fracture behavior with lower fracture energy. The intermetallic compounds (IMCs) formed in the solder joints before and after TCT were investigated. TCT induces a variety of structural variations in the solder joints, including slipping bands, whisker formation, the squeezing of the IMC layer, the formation of cavities, the rotation and pop-up of grain, and the deformation and rotation of the entire joint. The variations in fracture behavior induced by TCT are correlated with the structural variations in the solder joints.

scholarly journals Suppression of the Growth of Intermetallic Compound Layers with the Addition of Graphene Nano-Sheets to an Epoxy Sn–Ag–Cu Solder on a Cu Substrate

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 936 ◽  
Author(s):  
Min-Soo Kang ◽  
Do-Seok Kim ◽  
Young-Eui Shin
Keyword(s):  
Intermetallic Compound ◽  
Isothermal Aging ◽  
Solder Joints ◽  
Solder Paste ◽  
Shear Tests ◽  
Sac305 Solder ◽  
Epoxy Solder ◽  
The Relationship ◽  
Bonding Characteristics ◽  
Preventive Effects

This study investigated the suppression of the growth of the intermetallic compound (IMC) layer that forms between epoxy solder joints and the substrate in electronic packaging by adding graphene nano-sheets (GNSs) to 96.5Sn–3.0Ag–0.5Cu (wt %, SAC305) solder whose bonding characteristics had been strengthened with a polymer. IMC growth was induced in isothermal aging tests at 150 °C, 125 °C and 85 °C for 504 h (21 days). Activation energies were calculated based on the IMC layer thickness, temperature, and time. The activation energy required for the formation of IMCs was 45.5 KJ/mol for the plain epoxy solder, 52.8 KJ/mol for the 0.01%-GNS solder, 62.5 KJ/mol for the 0.05%-GNS solder, and 68.7 KJ/mol for the 0.1%-GNS solder. Thus, the preventive effects were higher for increasing concentrations of GNS in the epoxy solder. In addition, shear tests were employed on the solder joints to analyze the relationship between the addition of GNSs and the bonding characteristics of the solder joints. It was found that the addition of GNSs to epoxy solder weakened the bonding characteristics of the solder, but not critically so because the shear force was higher than for normal solder (i.e., without the addition of epoxy). Thus, the addition of a small amount of GNSs to epoxy solder can suppress the formation of an IMC layer during isothermal aging without significantly weakening the bonding characteristics of the epoxy solder paste.

scholarly journals Comprehensive Properties of a Novel Quaternary Sn-Bi-Sb-Ag Solder: Wettability, Interfacial Structure and Mechanical Properties

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 791 ◽  
Author(s):  
Kaipeng Wang ◽  
Fengjiang Wang ◽  
Ying Huang ◽  
Kai Qi
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Low Temperature ◽  
Strain Rate ◽  
Isothermal Aging ◽  
Solder Joints ◽  
Solder Matrix ◽  
Interfacial Structure ◽  
Solder Alloys ◽  
Cu Substrate

Sn-58Bi eutectic solder is the most recommended low temperature Pb-free solder but is also limited from the interfacial embrittlement of Bi segregation. Since the quaternary Sn-38Bi-1.5Sb-0.7Ag solder provides a similar melting point as Sn-58Bi eutectic, this paper systematically investigated the properties of this solder from wettability, bulk tensile properties, interfacial microstructure in solder joints with a Cu substrate, interfacial evolution in joints during isothermal aging and the shear strength on ball solder joints with effect of aging conditions. The results were also compared with Sn-58Bi solder. The wettability of solder alloys was evaluated with wetting balance testing, and the quaternary Sn-38Bi-1.5Sb-0.7Ag solder had a better wettability than Sn-58Bi solder on the wetting time. Tensile tests on bulk solder alloys indicated that the quaternary Sn-38Bi-1.5Sb-0.7Ag solder had a higher tensile strength and similar elongation compared with Sn-58Bi solder due to the finely distributed SnSb and Ag3Sn intermetallics in the solder matrix. The tensile strength of solder decreased with a decrease in the strain rate and with an increase in temperature, while the elongation of solder was independent of the temperature and strain rate. When soldering with a Cu substrate, a thin Cu6Sn5 intermetallic compound (IMC) is produced at the interface in the solder joint. Measurement on IMC thickness showed that the quaternary Sn-38Bi-1.5Sb-0.7Ag had a lower IMC growth rate during the following isothermal aging. Ball shear test on solder joints illustrated that the quaternary Sn-38Bi-1.5Sb-0.7Ag solder joints had higher shear strength than Sn-58Bi solder joints. Compared with the serious deterioration on shear strength of Sn-58Bi joints from isothermal aging, the quaternary Sn-38Bi-1.5Sb-0.7Ag solder joints presented a superior high temperature stability. Therefore, the quaternary Sn-38Bi-1.5Sb-0.7Ag solder provides better performances and the possibility to replace Sn-58Bi solder to realize low temperature soldering.

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