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Predicting the lifetime of solder joints undergoing thermal cycling is crucial for the electronics industry in order to guarantee a certain performance of their products in the field. Semi-empirical methods are often used to predict the average lifetime of the critical joints. However, to get a reliable failure probability the standard deviation must also be addressed. The deviation of the lifetime...
In this work the life time of solder joints of SMD components is studied under vibration loading. This kind of purely mechanical load is one of the main failure causes in automotive electronics. A test vehicle has been designed to enable vibration testing on SMD capacitors (size 0805). The test vehicle is distinguished with a line clamping and stripe shape which both leads to a concerted loading of...
Packaging engineers, in the search for the perfect packaging technology, are turning to three-dimensional packaging technologies that stack multiple dies/chips within a single package. Prevailing problems with stacked dies and clips are the tilting of the chips or clips due to the unbalanced bond line thickness of different solder attachments at different height levels or unbalanced weight distribution...
Solder balls, albeit mechanically soft, are the only structural support to the stacking of chip-scale packages (CSPs). This paper investigates the structural response of a Sn3.5Ag soldered bi-level stacked CSP module to board-level drop impact per the JEDEC criteria, and quantifies the stress buildup in the critical solder balls. The structural response is understood by tracking the force transmission...
For power module, the reliability evaluation of thermal fatigue life by power cycling has been prioritized as an important concern. Since in power cycling produces there exists non-uniform temperature distribution in the power module, coupled thermal-structure analysis is required to evaluate thermal fatigue mechanism. The thermal expansion difference between a Si chip and a substrate causes thermal...
Through-silicon-via (TSV) technology permits devices to be placed and wired in the third dimension. Currently, there is a strong motivation for the semiconductor industry to move to 3-D integration using the TSV approach due to many advantages of TSV application. However, there are also some challenges for stacked die package with TSVs. One of the challenges is thermo-mechanical reliability of multi-layer...
This paper presents the influence of the micro structure on the crack propagation in lead free solder joint. The author's group have studied the Manson-Coffin's law for lead free solder joint by using the isothermal fatigue test and FEM analytical approaches to establish the practicable evaluation of thermal fatigue life of solder joints, for example, for the Sn-Cu solder, because this solder is attracted...
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 study aims to predict the life and assess the reliability of electronic packages subject to multiple drop-impacts. Engineers used to adopt mechanics analysis as well as a certain life prediction model to predict the impact life of the package, and it is usually a deterministic value. However, drop test results show that the impact life of the package is not a single deterministic value but scatters...
This study describes board-level drop reliability of TFBGA subjected to JEDEC drop test condition which features an impact pulse profile with a peak acceleration of 1500G and a pulse duration of 0.5 ms. The solder ball is assumed as an elastoplastic model, and the other components are assumed to be linear elastic models. Both the global/local finite element method and the finite grid region method...
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...
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...
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...
Transient responses of 3D stacked-die package with through silicon via (TSV) structure under board level drop test load following the JEDEC standard are investigated using the Input-G finite element simulation method. In order to reduce the finite element mesh size the stacked-die package under investigation is modeled with details while the others are simplified as blocks with equivalent material...
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...
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