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Electronic components continue to high reliability, high performance, multi-functional, miniaturization direction. High-density integrated ball grid array (BGA) surface assembly technology is widely used in the field of microelectronics packaging. In this paper, the crack failure behavior of plastic ball grid array (PBGA) is studied under mechanical vibration load. The stress - strain distribution...
The major purpose of the mechanical stress screening is to screen out the products which have potential defects which lie in materials, design, process, and operation etc. If the screening is thorough before the products are shipped, the rate of the abnormal failure at the users' side can be eliminated or lowered significantly. The manufacturing lot which goes through appropriate screening will have...
Warpage, high stress in dies and solder joints are introduced in assembly process of a package-on-package component. In this paper, a finite element approach is proposed to predict the warpages and stresses during the full assembly process. By the techniques of element die and birth as well as restart method, the approach is able to transfer the stress and warpage in one process to the next so that...
Interfacial fracturing is the most important failure mode of solder joints. In this paper, interfacial stresses of Cu pad/solder interfaces are evaluated based on the theory of interfacial mechanics and the finite element method. Effects of solder joint shapes and solder materials on the stress intensity are investigated. The results show that Sn37Pb/Cu interface has greater stress intensity than...
This article deals with the mechanical stress of lead free soldered joints. During usage of electrical equipment are found structural changes of soldered joints, which can lead to cracks or failure of the solder joints. Therefore solder joints have influence on a total quality of electronic assembly. Mechanical tests are mainly used for resistance evaluation of components, devices and whole products...
Mechanical stresses, as vibrations, are the main common types of solicitation to which electronic equipment can be subjected during its useful life. For this reason drop or shock tests become important for such device; the use of a shaker system, able to produce sinusoidal and random vibrations, can simulate the operating conditions in a less expensive and faster way. In this paper the planning and...
A novel stacked converter construction technology, Power Sandwich that lends itself towards automation and high power densities has been proposed. In Power Sandwich technology, new double-sided SMT x-dim components that have uniform height are stacked between planar substrates in a few stack layers. Double-sided x-dim components are soldered to both top and bottom sides. The concept of Power Sandwich...
A complete halogen-free test vehicle was achieved by assembling five ball grid array (BGA) components with daisy-chain on an 8-layer high density interconnection (HDI) printed circuit board with a low-halide Sn1.0Ag0.5Cu (SAC105) Pb-free solder pastes for reducing the formation of Ag3Sn. Afterward a board-level cyclic bending test was enforced on the as-reflowed assemblies according to the JESD22-B113...
In this paper, steady-state creep behavior of lead free 80Au-20Sn solder was investigated at three different temperatures (i.e. 25degC, 75degC and 125degC) and a range of stress levels. Hyperbolic-Sine model was employed to characterize the creep properties of the lead free solder, constants in the model were determined through data fitting and were compared with that of other lead free solders.
Most accelerated temperature cycling (ATC) tests reported the observations that SnAgCu (SAC) solders have better thermal fatigue reliability than SnPb solders due to their lower creep strain rate. But material studies revealed that this is true only when stress level is below a certain level. When the stress level in the solder increases, eventually the creep strain rate of SAC solder may outgrow...
An array of accelerated temperature cycling (ATC) finite element (FE) simulations using ANSYStrade, and drop-impact finite element simulations using LS DYNAtrade, are used to find the optimum elastic modulus and coefficient of thermal expansion (CTE) for a stacked chip scale package. For the ATC simulations, Anand's constitutive model with properties for Sn96.5Ag3.0Cu0.5 (SAC305) and tin-lead eutectic...
Continuous increase in demand for product miniaturization, high package density, high performance and integration of different functional chips has lead to the development of three dimensional packaging technologies. Face-to-face silicon (Si) dies stacking is one of the three dimensional (3D) packaging technologies to form a high density module. In this work, a chip level stacked module was demonstrated...
One of the driving factors for a steady reduction in wafer and cell thickness is the present shortage of polysilicon feedstock combined with the need to reduce manufacturing costs in photovoltaic module production. Therefore materials and manufacturing processes must adapt to maintain acceptable mechanical yields and module reliability. The soldering of solar cell strings is a critical step in the...
The effect of thinning down the chip thickness, will affect the stress pattern in the chip and causes the chip to deform locally when the thickness of the chip is thinner than a certain critical value. Such a local deformation may cause sharp gradient of residual stress around the solder bumps and thus, various failures. This paper shows that by considering the effect of solder bumps on a 50 mum chip,...
Due to the smaller size of HDD, fault deformation of solder bumps is found more often. In order to study about a factor relating to fault deformation of solder bumps, the FEM is used to investigate stress performance. The results show that a small number of bumps positioned in a symmetric form have similar stress while a small number of bumps positioned in the asymmetric form have different stress...
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