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Three-dimensional structure has been achieved using interlayer connecting technology with double-side solder bump and the lifetime of the solder joints under thermal shock test has been forecasted by finite element method. The simulation result presents that the stress at the interface between 0.76mm solder bump and PCB is evidently higher than that in other places. The interface between 0.76mm solder...
The voiding phenomenon at the interface has been proven to weaken the mechanical properties of solder joints. The aim of this study was to investigate the influence of grain size on voiding propensity. Two kinds of substrates were used: high purity oxygen free copper (HPOFC) substrate and electrolytic tough pitch copper (ETPC) substrate. Grain size and voiding propensity were characterized by introducing...
A Sn-3.0Ag-0.5Cu (SAC) composite solder was fabricated by adding 0.1% weight percentage of multilayer graphene. The process steps are detailedly introduced in this paper. The physical, thermomechanical, wetting, mechanical properties were tested. Experimental results present that density and coefficient of thermal expansion of plain solder are higher than those of composite solder, while the thermal...
In recent years, the reliability under vibration loading has become a very important problem of modern electronic devices. And existing researches have shown that the results of natural frequencies and modal shapes by FEA (Finite Element Analysis) fit that of modal test well. But it is challengeable to execute the vibration fatigue life analysis rapidly and accurately. In this paper, a predict method...
This work was designed for low-temperature mechanical properties of the solder joints, the temperature is 293K, 223K, 173K, and 123K, in order to get the mechanical strength and mechanism of fracture at low temperature; Cryogenic temperature (77K) storage experiment is applied to get microstructure of internal solder joint, and the evolution of IMC and other microstructures, as well as solder joints'...
A new approach of rapid fabrication of intermetallic compounds (IMCs) solder joints at ambient temperature was investigated in this work. The high share strength Cu/Sn/Cu solder joints were obtained by using different strong electric currents 0.8KA, 0.9KA, 1.0KA, and 1.2KA for only about 0.2s. The Sn foils with the thickness of 10μm were used as solders. The results showed that with the current intensities...
In recent years, the reliability under vibration loading has become a very important problem of modern electronic devices. And existing researches have shown that the results of natural frequencies and modal shapes by FEA (Finite Element Analysis) fit that of modal test well. But it is challengeable to execute the vibration fatigue life analysis rapidly and accurately. In this paper, a predict method...
A new approach of rapid fabrication of intermetallic compounds (IMCs) solder joints at ambient temperature was investigated in this work. The high share strength Cu/Sn/Cu solder joints were obtained by using different strong electric currents 0.8KA, 0.9KA, 1.0KA, and 1.2KA for only about 0.2s. The Sn foils with the thickness of 10μm were used as solders. The results showed that with the current intensities...
This work was designed for low-temperature mechanical properties of the solder joints, the temperature is 293K, 223K, 173K, and 123K, in order to get the mechanical strength and mechanism of fracture at low temperature; Cryogenic temperature (77K) storage experiment is applied to get microstructure of internal solder joint, and the evolution of IMC and other microstructures, as well as solder joints'...
With the rapid development of three-dimensional integrated circuit packaging technology, through silicon via (TSV) has been used to bond the stacked chips. Cu-In Solid-Liquid Interdiffusion (SOLID) low temperature bonding is a promising process for TSV stacked chip interconnection. In this paper, shearing properties of Cu/In/Cu SOLID bonding joints was studied. A specific Cu-In solder joint was designed...
The growth evolution of intermetallic compounds and shear properties of various Sn-Ag-Cu solder joints were investigated by thermal cycling test. The numbers of thermal cycling tests were 0, 200, 400, 600, 800 cycles. Polyhedron particles composited of (Cu1−xNix)6Sn5 were observed after 400 thermal cycles and found in bulk solder away from the IMC layers after much more thermal cycles. Meanwhile,...
Electron backscatter diffraction (EBSD) technology combined with Orientation Imaging Microscopy (OIM) analysis method were employed to investigate the morphologies and orientations of Cu6Sn5 grains formed between Sn3.0Ag5.0Cu and polycrystalline copper, (001) (111) Cu single crystals under liquid-state condition. The reflow temperature was the main factor that influence the transformation of Cu6Sn...
Pure Sn, Sn-0.7Cu, Sn-1.5Cu and Sn-3.0Cu solder joints were fabricated by a laser reflow soldering method, and then they were aged at 125degC for various periods. After 600 hours treatment, we found that thickness of Intermetallic Compounds (IMCs) in the pure Sn solder joints was 54mum. However, in the solder joints with Cu addition, formation of AuSn4 IMCs was inhibited, and other two kinds of Sn-Cu-Au...
As the solder joints become increasingly small and contain only a few grains, their mechanical properties cannot be determined from conventional mechanical tests as with bulk samples, and there may be a considerable variation in mechanical behavior from joint to joint because of the anisotropy of mechanical properties. In this paper, elastic constants of single-crystal AuSn4 and AuSn2 were preliminarily...
Properties of body-centered tetragonal beta-Sn are highly anisotropic. The crystal orientation of the beta-Sn has a marked effect on the stress state in the SnAgCu solder joints. A finite element analysis has been performed of the thermal cycling of the SnAgCu solder and solder joints. Significant amounts of stresses at the solder/Cu interface and in the plane of the grain boundary was found. The...
With the development of optoelectronics and microelectromechanical systems (MEMS) packaging, laser soldering has become an extensively used interconnection technique in electronic manufacturing industry. Postsolder shift in assembling of such components is the most challenging issue to affect the packaging yields. To maintain a high coupling efficiency or accuracy, tight control of postsolder shift...
As-reflowed Sn-Ag-Cu solder joints in various diameters were found to contain only several beta-Sn crystal grains. With the solder joints increasingly miniaturized, there is no obvious change in the grain number in a solder joint. The aged Sn-Ag-Cu solder joints are composed of very limited number of beta-Sn crystal grains as well. It appears that the solder joint size and thermal aging have less...
To meet the urgent demands of future electronic packages, the solder joints have to become increasingly miniaturized. Compared to the large solder joints, mechanics behavior for the samll solder joints is very different, resulting in a series of reliability issues. Therefore, it is very important to understand the mechanics behavior of the small solder joints. In this paper, the shear test of the...
The self-alignment motion of optical fiber is critical to the low-cost and high-precision direct-coupling technology in optoelectronic packaging. In this research, the self-alignment method by using surface tension of molten solder and by adopting specific pad shape was proposed. First, the self-alignment model of solder joint in fiber attachment soldering was developed by using the public domain...
A dynamic model based on energy balance method for describing the solder profile evolution on orthogonal pads is proposed. This model combines the fluid mechanics and the surface physics and accounts for the inertial, viscous and gravitational forces, the interfacial tensions and the equilibrium contact angle of the spreading system. A corresponding computational scheme is developed without invoking...
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