Selective etching and hardness properties of quenched SAC305 solder joints

Purpose The purpose of this paper is to investigate the morphology of intermetallic (IMC) compounds and the mechanical properties of SAC305 solder alloy under different cooling conditions. Design/methodology/approach SAC305 solder joints were prepared under different cooling conditions/rates. The performance of three different etching methods was investigated: simple chemical etching, deep etching based on the Jackson method and selective removal of β-Sn by a standard three-electrode cell method. Phase and structural analyses were conducted by X-ray diffraction (XRD). The morphology of etched solder was examined by a field emission scanning electron microscope. The hardness evaluations of the solder joints were conducted by a Vickers microhardness tester. Findings The Ag3Sn network was significantly refined by the ice-quenching process. Further, the thickness of the Cu6Sn5 layer decreased with an increase in the cooling rate. The finer Ag3Sn network and the thinner Cu6Sn5 IMC layer were the results of the reduced solidification time. The ice-quenched solder joints showed the highest hardness values because of the refinement of the Ag3Sn and Cu6Sn5 phases. Originality/value The reduction in the XRD peak intensities showed the influence of the cooling condition on the formation of the different phases. The micrographs prepared by electrochemical etching revealed better observations regarding the shape and texture of the IMC phases than those prepared by the conventional etching method. The lower grain orientation sensitivity of the electrochemical etching method (unlike chemical etching) significantly improved the micrographs and enabled accurate observation of IMC phases.

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Effect of microwave operating power and reflow time on the microstructure and tensile properties of Sn–3.0Ag–0.5Cu/Cu solder joints

Soldering & Surface Mount Technology ◽

10.1108/ssmt-02-2021-0006 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Mardiana Said ◽

Muhammad Firdaus Mohd Nazeri ◽

Nurulakmal Mohd Sharif ◽

Ahmad Azmin Mohamad

Keyword(s):

Tensile Properties ◽

Design Methodology ◽

Solder Joints ◽

Reflow Time ◽

Sac305 Solder ◽

Cross Sectional ◽

Content Type ◽

Solder Reflow ◽

Microwave Hybrid Heating ◽

Si Wafer

Purpose This paper aims to investigate the morphology and tensile properties of SAC305 solder alloy under the influence of microwave hybrid heating (MHH) for soldering at different microwave parameters. Design/methodology/approach Si wafer was used as susceptor in MHH for solder reflow. Microwave operating power for medium and high ranging from 40 to 140 s reflow time was used to investigate their effect on the microstructure and strength of SAC305/Cu solder joints. The morphology and elemental composition of the intermetallic compound (IMC) joint were evaluated on the top surface and cross-sectional view. Findings IMC formation transformed from scallop-like to elongated scallop-like structure for medium operating power and scallop-like to planar-like structure for high operating power when exposed to longer reflow time. Compositional and phase analysis confirmed that the observed IMCs consist of Cu6Sn5, Cu3Sn and Ag3Sn. A thinner IMC layer was formed at medium operating power, 80 s (2.4 µm), and high operating power, 40 s (2.5 µm). The ultimate tensile strength at high operating power, 40 s (45.5 MPa), was 44.9% greater than that at medium operating power, 80 s (31.4 MPa). Originality/value Microwave parameters with the influence of Si wafer in MHH in soldering have been developed and optimized. A microwave temperature profile was established to select the appropriate parameter for solder reflow. For this MHH soldering method, the higher operating power and shorter reflow time are preferable.

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Performance of 96.5Sn–3Ag–0.5Cu/fullerene composite solder under isothermal ageing and high-current stressing

Soldering & Surface Mount Technology ◽

10.1108/ssmt-02-2020-0004 ◽

2020 ◽

Vol 33 (1) ◽

pp. 35-46 ◽

Cited By ~ 1

Author(s):

Guang Chen ◽

Xinzhan Cui ◽

Yaofeng Wu ◽

Wei Li ◽

Fengshun Wu

Keyword(s):

Solder Joint ◽

Composite Solder ◽

Solder Joints ◽

Experimental Results ◽

High Current ◽

Sac305 Solder ◽

Content Type ◽

Interfacial Imcs ◽

Current Stressing ◽

Isothermal Ageing

Purpose The purpose of this paper is to investigate the effect of fullerene (FNS) reinforcements on the microstructure and mechanical properties of 96.5Sn3Ag0.5Cu (SAC305) lead-free solder joints under isothermal ageing and electrical-migration (EM) stressing. Design/methodology/approach In this paper, SAC305 solder alloy doped with 0.1 Wt.% FNS was prepared via the powder metallurgy method. A sandwich-like sample and a U-shaped sample were designed and prepared to conduct an isothermal ageing test and an EM test. The isothermal ageing test was implemented under vacuum atmosphere at 150°C, whereas the EM experiment was carried out with a current density of 1.5 × 104 A/cm2. The microstructural and mechanical evolutions of both plain and composite solder joints after thermal ageing and EM stressing were comparatively studied. Findings A growth of Ag3Sn intermetallic compounds (IMCs) in solder matrix and Cu-Sn interfacial IMCs in composite solder joints was notably suppressed under isothermal ageing condition, whereas the hardness and shear strength of composite solder joints significantly outperformed those of non-reinforced solder joints throughout the ageing period. The EM experimental results showed that for the SAC305 solder, the interfacial IMCs formulated a protrusion at the anode after 360 h of EM stressing, whereas the surface of the composite solder joint was relatively smooth. During the stressing period, the interfacial IMC on the anode side of the plain SAC305 solder showed a continuous increasing trend, whereas the IMC at the cathode presented a decreasing trend for its thickness as the stressing time increased; after 360 h of stressing, some cracks and voids had formed on the cathode side. For the SAC305/FNS composite solder, a continuous increase in the thickness of the interfacial IMC was found on both the anode and cathode sides; the growth rate of the interfacial IMC at the anode was higher than that at the cathode. The nanoindentation results showed that the hardness of the SAC305 solder joint presented a gradient distribution after EM stressing, whereas the hardness data showed a relatively homogeneous distribution in the SAC305/FNS solder joint. Originality/value The experimental results showed that the FNS reinforcement could effectively mitigate the failure risk in solder joints under isothermal ageing and high-current stressing. Specifically, the FNS particles in solder joints can work as a barrier to suppress the diffusion and migration of Sn and Cu atoms. In addition, the nanoidentation results also indicated that the addition of the FNS reinforcement was very helpful in maintaining the mechanical stability of the solder joint. These findings have provided a theoretical and experimental basis for the practical application of this novel composite solder with high-current densities.

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The study on reliability of Ni-coated graphene doped SAC305 lead-free composite solders under high current-density stressing

Soldering & Surface Mount Technology ◽

10.1108/ssmt-11-2018-0043 ◽

2019 ◽

Vol 31 (4) ◽

pp. 261-270

Author(s):

Guang Chen ◽

Jiqiang Li ◽

Xinwen Kuang ◽

Yaofeng Wu ◽

Fengshun Wu

Keyword(s):

Solder Joint ◽

Current Density ◽

Composite Solder ◽

Solder Joints ◽

Experimental Results ◽

Lead Free ◽

Cathode Side ◽

High Current ◽

Sac305 Solder ◽

Content Type

Purpose The purpose of this paper is to investigate the effect of nickel-plated graphene (Ni-GNS) on the microstructure and mechanical properties of 96.5Sn3Ag0.5Cu (SAC305) lead-free solder joints before and after an electro-migration (EM) experiment. Design/methodology/approach In this paper, SAC305 solder alloy doped with 0.1 Wt.% Ni-GNS was prepared via the powder metallurgy method. A U-shaped sample structure was also designed and prepared to conduct an EM experiment. The EM experiment was carried out with a current density of 1.5 × 104 A/cm2. The microstructural and mechanical evolutions of both solder joints under EM stressing were comparatively studied using SEM and nanoindentation. Findings The experimental results showed that for the SAC305 solder, the interfacial intermetallic compounds (IMC) formulated a protrusion with an average height of 0.42 µm at the anode after 360 h of EM stressing; however, despite this, the surface of the composite solder joint was relatively smooth. During the stressing period, the interfacial IMC on the anode side of the plain SAC305 solder showed a continuous increasing trend, while the IMC at the cathode presented a decreasing trend for its thickness as the stressing time increased; after 360 h of stressing, some cracks and voids had formed on the cathode side. For the SAC305/ Ni-GNS composite solder, a continuous increase in the thickness of the interfacial IMC was found on both the anode and cathode side; the growth rate of the interfacial IMC at the anode was higher than that at the cathode. The nanoindentation results showed that the hardness of the SAC305 solder joint presented a gradient distribution after EM stressing, while the hardness data showed a relatively homogeneous distribution in the SAC305/ Ni-GNS solder joint. Originality/value The experimental results showed that the Ni-GNS reinforcement could effectively mitigate the EM behavior in solder joints under high current stressing. Specifically, the Ni particles that plated the graphene sheets can work as a fixing agent to suppress the diffusion and migration of Sn and Cu atoms by forming Sn-Cu-Ni IMC. In addition, the nanoidentation results also indicated that the addition of the Ni-GNS reinforcement was very helpful in maintaining the mechanical stability of the solder joint. These findings have provided a theoretical and experimental basis for the practical application of this novel composite solder with high current densities.

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Metal-Assisted Chemical Etching of Multicrystalline Silicon in HF/ Na2S2O8 Produces Porous Silicon

Materials Science Forum ◽

10.4028/www.scientific.net/msf.480-481.139 ◽

2005 ◽

Vol 480-481 ◽

pp. 139-144 ◽

Cited By ~ 13

Author(s):

T. Hadjersi ◽

N. Gabouze ◽

A. Ababou ◽

M. Boumaour ◽

W. Chergui ◽

...

Keyword(s):

Porous Silicon ◽

Chemical Etching ◽

Multicrystalline Silicon ◽

Etching Time ◽

X Ray Diffraction ◽

Experimental Conditions ◽

X Ray ◽

External Bias ◽

Etching Method ◽

Metal Assisted Chemical Etching

A new metal-assisted chemical etching method using Na2S2O8 as an oxidant is proposed to form a porous layer on a multicrystalline silicon (mc-Si). This method does not need an external bias and enables formation of uniform porous silicon layers, more rapidly than the conventional stain etching method. A thin layer of Pd is deposited on the mc-Si surface prior to immersion in a solution of HF and Na2S2O8. The characterisations of etched layer formed by this method as a function of etching time were investigated by scanning electron microscopy, X-ray diffraction (XRD), Energy-dispersive X-ray (EDX) and reflectance spectroscopy. It shows that the surface is porous and the etching is independent of grain orientation. In addition, reflectance measurements made with a variety of etching conditions show a lowering of the reflectance from 25 % to 6 % measured with respect to the bare as-cut substrate. However, this result can be improved by changing the experimental conditions (concentration, time, temperature, …).

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Reflow of tiny 01005 capacitor/SAC305 solder joints in protective atmosphere

Soldering & Surface Mount Technology ◽

10.1108/ssmt-10-2016-0021 ◽

2017 ◽

Vol 29 (3) ◽

pp. 144-150 ◽

Cited By ~ 4

Author(s):

Yeqing Tao ◽

Dongyan Ding ◽

Ting Li ◽

Jason Guo ◽

Guoliang Fan

Keyword(s):

Solder Joint ◽

Oxygen Concentration ◽

Solder Joints ◽

Protective Atmosphere ◽

Low Oxygen ◽

Reflow Process ◽

Sac305 Solder ◽

Content Type ◽

Placement Accuracy ◽

Component Assembly

Purpose This paper aims to study the influence of reflow atmosphere and placement accuracy on the solderability of 01005 capacitor/SAC305 solder joints. Design/methodology/approach The 01005 capacitors were mounted on OSP-coated pads, and the samples were fabricated in four different atmospheres, i.e. 200 ppm O2/N2, 1,000 ppm O2/N2, 3,000 ppm O2/N2 and air. After the reflow process, visual inspection and X-ray detection were carried out to examine the solder joint shapes and possible defects. Some of the samples fabricated in different conditions were cross-sectioned and the solder joint microstructures were analyzed. On the other hand, besides placing the components on their normal pad positions, a 50 per cent offset of the x-axis (long axis) or y-axis (short axis) was introduced into the chip mounter programs to evaluate the 01005 capacitor’s assembly sensitivity to placement accuracy. The process-induced defects were investigated. Findings Experimental results indicated that an N2-based protective atmosphere was necessary for 01005 type assembly, as it could obviously improve the 01005 solder joint quality, compared with the air condition. The protective atmosphere had little effect on the appearance, quality and microstructure of solder joints when the oxygen concentration was below 3,000 ppm. But a very low oxygen concentration could increase the risk of tombstoning defects for the assembly process. The N2-based protective atmosphere containing 1,000-2000 ppm O2 was acceptable and appropriate for the assembly of tiny components. Originality/value The results of this work provide a set of reflow process parameters and recommendations for 01005 size component assembly in manufacturing.

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Variability of Mechanical Cycling Durability of SAC305 Solder Joints: Model-Based Assessment using Grain-scale Modeling of Cyclic Shear Loading

2021 22nd International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE) ◽

10.1109/eurosime52062.2021.9410828 ◽

2021 ◽

Author(s):

Abhishek Deshpande ◽

Qian Jiang ◽

Abhijit Dasgupta

Keyword(s):

Solder Joints ◽

Shear Loading ◽

Sac305 Solder ◽

Cyclic Shear ◽

Model Based ◽

Scale Modeling ◽

Mechanical Cycling

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Study in performance and morphology of polyamide 12 produced by selective laser sintering technology

Rapid Prototyping Journal ◽

10.1108/rpj-01-2017-0010 ◽

2018 ◽

Vol 24 (5) ◽

pp. 813-820 ◽

Cited By ~ 9

Author(s):

Junjie Wu ◽

Xiang Xu ◽

Zhihao Zhao ◽

Minjie Wang ◽

Jie Zhang

Keyword(s):

Selective Laser Sintering ◽

Polarized Light ◽

Chain Scission ◽

High Energy ◽

Laser Sintering ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Content Type ◽

X Ray ◽

Polyamide 12

Purpose The purpose of this paper is to investigate the effect of selective laser sintering (SLS) method on morphology and performance of polyamide 12. Design/methodology/approach Crystallization behavior is critical to the properties of semi-crystalline polymers. The crystallization condition of SLS process is much different from others. The morphology of polyamide 12 produced by SLS technology was investigated using scanning electron microscopy, polarized light microscopy, differential scanning calorimetry, X-ray diffraction and wide-angle X-ray diffraction. Findings Too low fill laser power brought about bad fusion of powders, while too high energy input resulted in bad performance due to chain scission of macromolecules. There were three types of crystal in the raw powder material, denoted as overgrowth crystal, ring-banded spherulite and normal spherulite. Originality/value In this work, SLS samples with different sintering parameters, as well as compression molding sample for the purpose of comparison, were made to study the morphology and crystal structure of sintered PA12 in detail.

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Growth mechanism and characterization of ZnO nano-tubes synthesized using the hydrothermal-etching method

Chemical Papers ◽

10.2478/s11696-009-0082-y ◽

2009 ◽

Vol 63 (6) ◽

Cited By ~ 10

Author(s):

Yan Li ◽

Chuan-Sheng Liu ◽

Yun-Ling Zou

Keyword(s):

Room Temperature ◽

Morphological Analysis ◽

Diffraction Field ◽

X Ray Diffraction ◽

X Ray ◽

Room Temperature Photoluminescence ◽

Etching Method ◽

Nano Rods ◽

Two Stages

AbstractZnO nano-tubes (ZNTs) have been successfully synthesized via a simple hydrothermal-etching method, and characterized by X-ray diffraction, field emission scanning electron microscopy and room temperature photoluminescence measurement. The as-synthesized ZNTs have a diameter of 500 nm, wall thickness of 20–30 nm, and length of 5 µm. Intensity of the plane (0002) diffraction peak, compared with that of plane (10$$ \bar 1 $$0) of ZNTs, is obviously lower than that of ZnO nano-rods. This phenomenon can be caused by the smaller cross section of plane (0002) of the nano-tubes compared with that of other morphologies. On basis of the morphological analysis, the formation process of nano-tubes can be proposed in two stages: hydrothermal growth and reaction etching process.

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