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With the rapid growth in the mobile industry, Package-on-Package (PoP) technology has been widely adopted for the 3D integration of logic and memory devices within mobile handsets and other portable multimedia products. The PoP solution offers significant advantages, including increased density through stacking logic and memory devices in the same formfactor and a high degree of flexibility for variable...
Thermal ageing of micro-porous sintered silver was examined under high temperature exposure. Silver sinter paste was printed in a shape of a tensile specimen on a Cu substrate, and was sintered at 250 °C for 1 h in air with no pressure. Specimens were exposed for 0, 50, 500, and 1000 h at 250 °C. Tensile strength was obtained at each ageing stage at a strain rate of 1.0×10−5/s. The evolution of microstructure...
In this study, the effect of pad shape on current density and temperature distributions in solder joints has been investigated by three dimensional thermo-electrical finite element analysis. The simulation results show that square, hexagonal, octagonal and rounded pads with the same thickness/volume generate different current density and temperature distributions. The maximum current densities in...
3-D finite element models of SOP (Small Outline Package) were constructed, in which Anand visco-plasticity constitutive equation was used to describe the mechanic behavior of solder joint. The solder joint deformation and stress distribution with five kinds of lead shapes were researched. The experimental program for the identification of numeri3cal simulation was performed with three kinds of lead...
Thinner organic BGA packages typically lead to higher warpage before surface mount which, after reflow, causes package corner solder joints (SJ) to have higher stand-off compared to solder joints in the package center. Hence the solder joints at package corners can change from typical barrel shape to an elongated hour-glass shape. Conventional understanding of the impact of SJ height on temperature...
3-D finite element models of SOP (Small Outline Package) were constructed, in which Anand visco-plasticity constitutive equation was used to describe the mechanic behavior of solder joint. The solder joint deformation and stress distribution with five kinds of lead shapes were researched. The experimental program for the identification of numeri3cal simulation was performed with three kinds of lead...
Solder joint geometry feature is important for packaging miniaturization design. To improve the thermo-mechanical reliability of lead-free packaging, a copper column interconnect with idealized solder joint shape, composed of a double-funnel shaped copper column and two lead-free solder fillets at both ends of the column, was designed to replace the high-Pb solder column interconnect in ceramic column...
This study focuses on the development of a highly reliable solder bumping solution by the optimization of bump height and shape for flip-chip mounting of large die directly on PCB without the use of underfill. To achieve the goal, an elongated solder joint with an optimized shape has been developed that demonstrated far superior board-level thermo-mechanical reliability to that of the conventional...
Miniaturization of electronic components driven by “thin and light” products in portable and consumer electronics has lead to thinner and smaller Ball Grid Array (BGA) packages. Surface Mount (SMT) processes for these smaller and thinner packages present significant challenges, and the reduced Z-height requirements were met with improved process solutions. This study is focused on two technology options:...
The purpose of this paper is to compare the ability of solder joint with different shape (hourglass-shaped, barrel-shaped and cylinder-shaped) to resist destruction under drop impact loadings. Three 3D finite element models of VFBGA (very-thin-profile fine-pitch BGA) packages, including different shape of solder joints, are established respectively. According to the condition B in the drop test standard...
The paper proposes a method that realized the solder joints assembly quality fault diagnosis. After an analysis of fuzzy fault diagnosis principle of SMT products, geometrical shape parameters which reflected PQFP solder joint quality were studied. Reasonable shape of components solder joint was built based on minimal energy principle. Then through the study of the real solder shape, the graphic token...
This paper presents the high reliability design method for lead-free solder joints on chip components, and that is able to evaluate effect of soldering process for solder joint shape. Coupled analysis of structure analysis and flow analysis was proposed for replication of solder wetting and behavior of electric components at the same time. The analysis methods enable to evaluate complex mechanism...
This paper presents a method mining the worst thermal fatigue life of solder joints on chip components used in vehicle electronics. Thermal fatigue life of crack initiation and propagation were calculated by using the finite element method. Statistical analysis of thermal fatigue life in the solder layer below the chip component was carried out. A sample of dispersed fatigue lives was generated by...
Board level solder joint reliability performance during drop test is a critical concern to semiconductor and electronic product manufacturers. In this paper, a new compliant Wafer Level Package technology is proposed which can accommodate the CTE mismatch between the chip and PCB substrate and consequently should be more reliable without the application of underfill. The purpose of this study is to...
This paper targets the reliability of electronics components, specially avionics and automotive electronic system, under random vibration conditions. A fatigue life estimation procedure is presented and each step of procedure is explained. Finite Element model of the test vehicle is built in ANSYS. The model is first validated by correlating the natural frequencies, mode shapes and transmissibility...
This paper presents mining the worst case of thermal fatigue life of solder joints on chip components used in vehicle electronics. Typical 36 cases with various solder shapes were examined. Thermal fatigue life including not only the crack initiation but also crack propagation was evaluated by using the finite element method. Based upon the case study's results, it was found that when a crack propagates...
To increase miniaturization, CSWLP (chip size wafer level packaging) has been developed. However, the difficulty to get good solder joint reliability leads to manufacture only small CSWLP modules. Different underfill methods are evaluated here, by measurements and simulations: results prove that underfill is necessary, but a bad choice can also decrease the reliability. An original method called ldquore-enforcementrdquo...
Four process parameters including, the pad length, the pad width, the stencil thickness and the stand-off, are chosen as four control factors, and by using an L25(56) orthogonal array, the no-fillet chip component solder joints shapes with 25 different process parameters combinations are established. And then all the shape prediction models of the 25 solder joints are built through the Surface Evolver...
The existing automatic optical inspection (AOI) equipment can be used to check out the defect of the electronic products, such as solder bridging, tomb stone and so on. Based on the existing AOI, a new intelligent optical inspection analysis (IOIA) technology is brought forward in this paper. The method, which combines off-line analysis and on-line contrast, is employed in the IOIA technology. That...
This paper deals with hand lead-free soldering process optimization. The work is focused on the impact of solder pads shape in combination with solder pads finish on lead-free solder joints reliability.
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