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The performance of high power packages is limited in part by the interfacial resistance between the die and lid or heat sinks. The thermal resistance depends on the shape of mating surfaces, bondline thickness (BLT) of the thermal interface material (TIM), bulk thermal conductivity and contact resistance. This paper focuses on warpage modeling methods to predict the local variation of TIMs and its...
In a typical power electronics package, a grease layer forms the interface between the direct bond copper (DBC) layer or a baseplate and the heat sink. This grease layer has the highest thermal resistance of any layer in the package. Reducing the thermal resistance of this thermal interface material (TIM) can help achieve the FreedomCAR program goals of using a glycol water mixture at 105degC or even...
The dimensions and power dissipation information of various commercial handheld electronics were collected to find benchmarking size and power ranges. The relationship between device size parameter, defined as total volume divided by external surface area, and the power dissipation was determined. Three dimensional finite element models were used to model the conduction, natural convection, and surface-to-surface...
This paper describes the phase growth of Sn-3.0Ag- 0.5Cu solder joints by mechanical cyclic loading. The objective of this paper is to clear the influence of temperature and strain to the phase growth. It is very important to evaluate the life time of crack initiation in Sn-3.0Ag-0.5Cu solder joints under thermal cycles. A mini-lap joint type shear specimen was used to evaluate the influence of temperature...
A study of the performance of different Sn based solder alloys applied for large to small sized solder interconnects was undertaken. From the theoretical and experimental investigations on creep, fatigue and brittle fracture behaviors the paper focuses on the low cycle fatigue performance in test and field thermal environments. Special focus was put on a newly developed highly creep resistant solder...
The problem of solder joint fatigue is essentially one of fatigue crack growth. However, little work has been done that enables fatigue life predictions by means of tracking the crack front and its growth. Most popular fatigue life models are empirical and therefore, limited in their applicability and in the insight they provide. Analytical fracture mechanics approaches such as the Paris Law and the...
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...
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...
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...
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,...
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...
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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