A study of Ag additive methods by comparing mechanical properties between Sn57.6Bi0.4Ag and 0.4 wt% nano-Ag-doped Sn58Bi BGA solder joints

Sun, Huayu; Li, Qingqian; Chan, Y.C.

doi:10.1007/s10854-014-2177-7

Cited by 38 publications

(26 citation statements)

References 24 publications

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“…This means that the interfacial Cu-Sn IMCs growth under isothermal aging is a diffusion-controlled process. This conclusion is agreed with other researchers' results [26][27][28] on various soldering systems. For the Sn-58Bi/Cu soldered joints, it is reasonable that the k value at 393 K is greater than that of 373 K, as indicated in Table 1.…”

Section: Growth Of Cu-sn Imc During Isothermal Solidstate Agingsupporting

confidence: 93%

A study on the interfacial reaction of Sn58Bi/Cu soldered joints under various cooling and aging conditions

Huang

et al. 2015

J Mater Sci: Mater Electron

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As one of the important factors affecting the quality of soldered joints, the interfacial intermetallic compound (IMC) formed at the solder/substrate interface is of increasing concern to researchers. Thus, the growth behavior of interfacial IMC in Sn58Bi/Cu solder joints was investigated as different cooling methods-quenched water, cooling in air, and cooling in a furnace during reflowing were used. In this work, the effect of cooling rate on interfacial IMC growth is studied in Sn58Bi/Cu system. Morphology and growth kinetics of the interfacial Cu-Sn IMC under various cooling rates were studied. It was found that only scallop-like Cu 6 Sn 5 IMC layer was observed between solder and Cu substrate in cases of water cooling and air cooling, while bi-layer composed of scallop-like Cu 6 Sn 5 and planar Cu 3 Sn was detected under furnace cooling due to sufficient reaction time to form Cu 3 Sn between Cu 6 Sn 5 IMC and Cu substrate which resulted from slow cooling rate. Samples with different reflow cooling rate were further thermal aged at 373 and 393 K, respectively. The results showed that the morphology of interfacial Cu-Sn IMC layer would transform from scallop-like to planar-like with increasing aging time, and the thickness of IMC increased linearly with square root of aging time. The growth constants of interfacial IMC layer were obtained and compared for different cooling rates and aging temperatures, indicating that the IMC layer thickness increased faster in samples under slow cooling rate than the fast cooling ones under the same aging condition, and higher aging temperature could result in faster growth of IMC layer. The interfacial Cu 6 Sn 5 grains gradually transformed to facet prismatic shape as the cooling rate decreased, and the grain size increased dramatically as the samples were cooled in furnace, comparing with that of samples cooled in water and air.

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Section: Growth Of Cu-sn Imc During Isothermal Solidstate Agingsupporting

confidence: 93%

A study on the interfacial reaction of Sn58Bi/Cu soldered joints under various cooling and aging conditions

Huang

et al. 2015

J Mater Sci: Mater Electron

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“…The doped solder balls with diameter around 320 lm were prepared via the reflow soldering. The details of the procedure can be found in our former paper [12]. After that, the doped solder balls were reflowed onto the nickel/copper pads with diameter of 280 lm to fabricate the doped solder joints.…”

Section: Methodsmentioning

confidence: 99%

“…The non-uniform distribution of doped particles will lead to the degradation of reinforcement caused by long-time aging [12]. What's more important, the changes of weight percent of doped particles in the solder joints will affect the accuracy of quantitative experiments seriously, such as the researches on the relationship between the properties of the doped solder joints and the doping amount.…”

Section: Introductionmentioning

confidence: 99%

The impact of reflow soldering induced dopant redistribution on the mechanical properties of CNTs doped Sn58Bi solder joints

Sun

Chan

2015

J Mater Sci: Mater Electron

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This research was intended to establish a scientific relationship between the changes of the weight percent of CNTs in the solder blocks and the changes of mechanical properties of the doped solder joints. The impact of reflow soldering induced dopant redistribution has been detailedly discussed. It was proved to be a principle reason that led to the changes of the weight percent of CNTs in the doped solder joints, and finally influenced the mechanical properties. The drag force caused by the outward flow of the solder flux and the buoyancy force caused by the density gap were the main inducing factors for the redistribution. By experimental methods, CNTs doped Sn58Bi solder pastes with the doping amount of 0.025, 0.05, 0.100, 0.150 and 0.200 wt% were studied to analyze this phenomenon. Our findings showed that with doping amount of 0.100 wt%, the doped solder block seemed saturated. After doping more CNTs, the final weight percent of CNTs was hardly increased. Also, the excess CNTs preferred to aggregate at the near surface region of the solder block, making the surface became darker and coarser. To analyze the real conditions, CNTs doped Sn58Bi solder joints with different original doping amount were studied to detect the changes of mechanical properties. According to the results, the highest shear stress was found to be 77.3 MPa with the doping amount of 0.050 wt%. After the doping amount overpassed 0.100 wt%, the shear stress decreased sharply. Also, via morphology observation, the doped CNTs were found aggregated at the interface of the solder joints seriously with the doping amount of 0.200 wt%.

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“…However, their performance is not comparable to Sn-37Pb materials. In order to improve the performance of Sn-Bi-Ag based lead-free solder materials, various methods, such as the addition of indium [5,6] and nano-additives [7], have been used. The addition of indium improves the wettability and decreases the melting point.…”

Section: Introductionmentioning

confidence: 99%

Role of Voltage and Gas Pressure in Determining the Mean Diameter of Sn-Bi-Ag Intermetallic Compound Nanoparticles Formed by Pulsed Wire Discharge

Jeong¹,

Min²,

Kim³

et al. 2017

Korean J. Met. Mater.

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Nanoscale Sn-Bi-Ag compound powders were successfully synthesized using the pulsed wire discharge (PWD) method. In PWD, when a high current is passed through high-density metal wires, the wires explode because of resistance heating, forming fine particles or metal vapor. In this study, we used Sn-Bi and Ag wires in order to obtain three-component nanopowders. A high current was applied to the wires between the electrodes in a N2 atmosphere. We discussed the results based on the K factor, which is the ratio of the charging energy of the capacitor to the vaporization energy of the wire. The three-component (Sn-Bi-Ag) nanoparticles were synthesized under a N2 atmosphere at 4 and 6 kV. From the particle-size distribution curves, it was found that the mean particle diameter (D1) values of the Sn-Bi and Ag nanopowders were within the range of 16.32-42.37 nm under each condition. The melting point of the Sn-Bi-Ag nanoparticles was found to be within the range of 188.68-214.97 ℃, which is about 40 ℃ lower than that obtained from the phase diagram and computational thermodynamics of the Sn-Bi-Ag system. In this study, the nanopowders were obtained by subjecting the wires at extreme energies, to improve their solid solubility. † (

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A study of Ag additive methods by comparing mechanical properties between Sn57.6Bi0.4Ag and 0.4 wt% nano-Ag-doped Sn58Bi BGA solder joints

Cited by 38 publications

References 24 publications

A study on the interfacial reaction of Sn58Bi/Cu soldered joints under various cooling and aging conditions

A study on the interfacial reaction of Sn58Bi/Cu soldered joints under various cooling and aging conditions

The impact of reflow soldering induced dopant redistribution on the mechanical properties of CNTs doped Sn58Bi solder joints

Role of Voltage and Gas Pressure in Determining the Mean Diameter of Sn-Bi-Ag Intermetallic Compound Nanoparticles Formed by Pulsed Wire Discharge

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