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The objective of this paper is presenting two energy based failure criteria and applying them in reliability simulations of Complementary Metal Oxide Semiconductor (CMOS) structures. Of particular interest are the Back-End-Of-Line (BEOL) interconnect layers and their interfaces. It is an accepted fact that process-induced flaws due to a mismatch in the Coefficients of Thermal Expansion (CTE) of the...
A series of studies have been conducted for mechanical behavior of elastic thin films on compliant substrates. Under tension, the film may fracture by growing channel cracks. The driving force for channel cracking (i.e., the energy release rate) increases significantly for compliant substrates. Moreover, channel cracking may be accompanied by interfacial delamination. For a film on a relatively compliant...
In this paper, principal component regression models (PCR) have been investigated for reliability prediction and part selection of area package architectures under thermo- mechanical loads in conjunction with stepwise regression methods. Package architectures studied include, BGA packages mounted on CU-CORE and NO-CORE printed circuit assemblies in harsh environments. The models have been developed...
Thermal simulation had been conducted on flip chip packages with copper heat spreader and better thermal performance was achieved. The copper heat spreader was able to enhance the heat spreading from the die but thermal performance was affected due to the thin layer of thermal interface materials. It was observed that thermal performance gain can be as high as 30% from heat spreader. Ansys thermo-mechanical...
Sintered nanoscale silver paste was used as thermal interface material in an electronic package. Based on the microstructure of the sintered silver paste, die shear stress-strain curves and thermal cycling test results, a model combined with the model of Navarro-de los Rios and small cracks interaction physical model is put forward to predict the thermal fatigue lifetime of the sintered nanoscale...
This paper addresses the reliability of flip-chip on flex (FCOF) assemblies glued with an Ag-particle filled anisotropic conductive adhesive (ACA). As the description of FCOF failure gives still much scope for speculation, a physics of failure based approach is developed here, taking into account the changing thermo-mechanical properties of the ACA under temperature and moisture. A failure hypothesis...
Interest in the use of smart-structure technology for noise and vibration reduction in several applications has been on the rise in recent years. It has been established that significant gains in structures performance can be achieved through active vibration control. In this study a 3-D finite element analysis for cantilever plate structure excited by patches of piezoelectric actuator is presented...
For power devices, the reliability of thermal fatigue induced by power cycling has been prioritized as an important concern. Because, the power device like the converter system is the key in vehicle applications. So, high reliability is demanded by reduction in the size and high power capacity. Therefore shortening reliability evaluation is demanded using finite element method (FEM). Since power cycling...
In this paper, the accuracy of optical measurements based on digital image correlation (DIC) with ultra high-speed imaging has been investigated for full-field measurement of transient strain in various board assemblies subjected to shock in various orientations. Previous researchers have measured the transient-dynamics of board assemblies with high-speed imaging in conjunction with high-speed image...
Electrical contacts may be subjected to wear because of shock, vibration, and thermo-mechanical stresses resulting in fretting, increase in contact resistance, and eventual failure over the lifetime of the product. Previously, models have been constructed for various applications to simulate wear for dry unidirectional-sliding wear of a square-pin [1], unidirectional sliding of pin on disk [2], and...
Electronic assemblies may often be approximated as layered structures during their analysis. Therefore, the thermal stresses that develop in bonded layers is of interest in the modeling of reliability of electronic assemblies. At the present time, analytical models of thermal stresses in multilayered assembly, inspired by the classical work of Timoshenko, exist in the literature. The current approaches...
Drop testing is performed on stacked chip scale packages in eight configurations, including the use of two types of commercially available underfills. Full failure analysis using techniques such as dye penetrant and scanning electron microscopy (SEM) is performed. Corresponding explicit finite element simulations are performed using ANSYSreg LS-DYNA. These simulations are used to determine a suitable...
The wafer level package (WLP) is a cost-effective solution for the electronic package, and has been increasingly applied during recent years. In this study, a new packaging technology developed based on the concepts of the WLP, the panel base package (PBP) technology, is proposed in order to further obtain the capability of signals fan-out for the fine-pitched integrated circuit (IC). In the PBP,...
Predicting reliability of solder joints requires a thorough understanding of solder constitutive behavior. Recent studies on SnAgCu solder alloys have reported that pre-test conditions of aging-time and aging-temperatures can be factors that significantly affect solder constitutive behavior. The results presented here are a part of ongoing efforts to construct constitutive models that can predict...
In this work, free drop impact responses of printed circuit boards (PCBs) mounted in cellular phones has been investigated to assess their dynamic responses and investigate the effects of fastening methods. The digital image correction (DIC) method was used in order to measure a full-field deformation of PCBs during drop from a certain height. Three different fastening techniques which have point...
The fatigue life considering dispersion of solder joints on chip resistor was investigated by experimental approach and analytical approach. The significant difference of crack propagation ratio was found each specimen by experimental approach. However, it is difficult to clarify the reasons of the difference for the fatigue life of solder joint quantitatively. So, the analytical approach that estimates...
Increased power density in electronics systems is limiting the ability of air cooling to provide adequate cooling for the components in the systems. Thermoelectric cooling are solid state and highly reliable devices that can be used as either refrigeration or heat pump. The use of thermoelectric device for hot spot cooling has attracted significant research. Under specific conditions, a well-selected...
Solder void often is one of main defects when assembling power quad flat no-lead (PQFN) packages. The voids need to be reduced as they are detrimental to package's thermal and mechanical performances. While formation of solder voids is affected by many factors such as solder paste, silicon die backside, lead frame, solder reflow profile, die bonding process, etc., this study focuses on the effects...
Solder void is a common defect when assembling power quad flat no-lead (PQFN) packages and is harmful to package's thermal and mechanical performances. Solder reflowing process, including reflow temperature, time, atmosphere, oven capability and so on, plays significant roles in solder void formation. In this study, the effects of reflow atmosphere, nitrogen gas and forming gas (mixture of 5% hydrogen...
We propose a new concept of mounting structure for high- temperature operable power semiconductor devices such as Silicon Carbide (SiC) or Gallium Nitride (GaN) with high reliability. The proposed structure is composed by high purity aluminum (Al) as a circuit metal on substrate and high- temperature resistant joint material as a chip joint layer. In this structure, the circuit metal can deform easily...
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