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3D packaging is one of the main emerging markets especially for mobile application within the last view years. Mobile devices are exposed and hence need to be reliable under to vibration or mechanical shock conditions. Therefore, material properties covering strain rate dependency have to be at hand within reliability studies. Miniature bulk specimens were utilized to gain stress and strain data at...
The demand for flip chip devices is rising to meet increasingly strict requirements for smaller package size, multiple-die stacking and higher interconnection densities. There are, however, two major issues facing the flip chip process, which are reliability impact by the stresses induced in the solder joints during reflow and high cost for underfill process and materials. Current alternatives to...
Progressive materials damage process in solder joint under cyclic shear deformation is examined in this study. A 3-D finite element model of a single reflowed SAC405 solder specimen is developed for this purpose. Cyclic relative displacement cycles between zero and 1.0 mm at displacement ramp rate of 2.0 mm/sec. is applied in the direction parallel to the solder/pad interface. Strain rate-dependent...
This study examines evolution characteristics of inelastic strains and materials damage in Sn-4Ag-0.5Cu (SAC405) solder joints of a BGA package under cyclic mechanical stressing. For this purpose, a finite element model of the assembly under four-point bend test set-up is employed. Strain rate-dependent response of the solder is represented by Anand model. Progressive damage in the solder joint is...
On one hand, with the rapid increase of integrated circuits (ICs) I/O number, the traditional package technique does not meet the need of pioneer development. On the other hand, three-dimensional integrated circuits (3-D ICs) become more and more popular to satisfy the multi-function chip development. One of the best solutions of these needs is the ultra-fine pitch micro-bumps. The micro-bumps can...
In this decade, the Moore's law does not fit the trend of technological improvement any more. In order to keep the increasing rate of device density and I/O numbers, the size of devices shrink rapidly. In this kind of condition, the stack of integrated circuit (IC), which is also called three-dimensional integrated circuits (3-D ICs), is a preferable solution of the next-generation products. There...
In this paper, thick film chip resistors with two different types of solder alloys namely SnPb and SnAgCu have been evaluated for the effects of the solder alloy elemental composition on the solder joint failures under cyclic temperature loading conditions. The creep properties of both solders have been modelled using the Garofalo equation and the creep strain energy density has been extracted and...
In recent years, electronic product have been demanded more functionalities, miniaturization, higher performance, reliability and low cost. Therefore, IC chip is required to deliver more signal I/O and better electrical characteristics under the same package footprint. None-Lead Bump Array (NBA) Chip Scale Structure is then developed to meet those requirements offering better electrical performance,...
The ultra fine pitch micro bump became the future trend due to the development of 3D IC. In this research, three-dimensional simulation was employed to examine the temperature distribution in micro SnAg solder bumps. According to the result, the temperature distribution in solder bump of micro bump is nearly uniform. In addition, the hot side is near the substrate side, whereas the cold side is near...
Thus far, there is a severe lack of understanding about interfacial fracture and impact behavior of the microscale lead-free solder interconnects. In this study, the finite element simulation and analytical method were used to characterize the interfacial fracture and impact behavior at the interfaces of the microscale Sn-Ag-Cu solder joints. The intersection of a linear microcrack tip upon Sn-Ag-Cu...
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...
The thermal fatigue and mechanical fatigue are the two main failure modes for board level solder joint in SMT. The comparison investigation of thermal fatigue and mechanical fatigue behavior of solder joint are carried out by experimental method in this study. The surface mounted test PCB is used and two kinds of solder materials, including SAC305 and Sn37Pb, are considered. It is shown that lead-free...
The purpose of this paper is to compare the abilities of two kinds of solder joints (63Sn37Pb and 96.5Sn3.0Ag0.5Cu) to resist thermal fatigue, and to predict their thermal fatigue lives. First, ten 2D simplified models of PBGA (Plastic Ball Grid Array package) structure with different shape of solder joints, which are obtained from surface mount experiments, are established using finite element software...
Wafer level Chip Scale Package (WLCSP) fulfills the demand for small, light, and portable handheld electronic devices, and it is one of the most advanced packaging concepts. When the WLCSP was assembled on board level, the connection, i.e. solder joints are generally the critical and challenging issue for the whole device's reliability. In addition to the shape and material of solder joints, the material...
Thermo-mechanical reliability for 3D stacked-die package with through silicon via (TSV) is studied through finite element simulation with sub-modeling technology, and design of experiments (DoE) using Taguchi experiments and analysis method. Firstly, the thermo-mechanical responses of micro-solder joints between stacked-die and copper via/SiO2 insulated layer structures are investigated under accelerated...
The line-type Cu/Sn/Ni interconnects were used to determine the effect of electromigration (EM) on the Cu-Ni cross-interaction under the current density of 1.0×104 A/cm2 at 150 °C for 100 h and 200 h. For the purpose of comparison, the line-type Cu/Sn/Ni interconnects were also aged at 150 °C for 100 h and 200 h. After soldering, Ni3Sn4 and Cu6Sn5 IMCs formed at the Sn/Ni and Sn/Cu interfaces, respectively...
The changeover from eutectic Sn-Pb solders to lead-free solders has been driven by environmental concerns and market accessibility in the last few years. Though a number of creep constitutive laws of lead-free solder have been reported due to the importance of creep in solder joint failure in the electronic packaging, these constitutive laws often show great variations across the applicable stress...
Pin-through-hole (PTH) connection is one of the most common types of connection between components and circuit board. Taking the printed circuit board (PCB) of the typical electronic product air conditioner as research object, thermal fatigue behavior and failure mechanism of the through-hole solder joints were investigated by accelerated aging experiments and finite element analysis (FEA). Results...
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...
A new structural effect that was developed based on the concepts of the cantilever beams has been proposed in order to illustrate the measurement divergence of nanoindentation test for Cu6Sn5 IMCs. Cu6Sn5 IMCs were fabricated in Sn3.5Ag/Cu solder joints by wetting reaction at 250°C and subsequent thermal aging, and measured by nanoindentation. In this study, the extra displacement created by the cantilever-like...
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