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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,...
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...
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...
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...
In this research, we evaluate the potential for air cooling to meet the stringent cooling requirements of advanced automotive power electronics. We assess air cooling of power electronic components using laminar airflow micro-channel heat exchangers. Comparisons are made with ethylene glycol systems commonly used in tandem with engine cooling. Our analysis shows that despite a lower coefficient of...
Porous metal foams, inserted into the channels of a liquid cold plate, can be used to enhance forced convection and flow boiling heat transfer and may be especially useful for direct, dielectric liquid cooling of electronic and photonic components. This study explores the thermofiuid characteristics of three porous copper foam configurations: 95% porosity and 10 PPI, 95% porosity and 20 PPI, and 92%...
Two-phase pumped-loop systems are being actively explored for the cooling of high-heat-flux electronics cooling because of their compactness and low thermal resistance. A typical two-phase pumped loop consists of a microchannel heat sink based evaporator, a finned-tube condenser, a reservoir, and a positive displacement pump. In the present study, the physics of operation of a two-phase pumped-loop...
Rapid development in the design of electronic packages for modern high-speed computers has led to the demand for effective methods of chip cooling. The primary concerns in thermal management applications are high thermal conductivity, large specific surface area and low weight. Graphite foams which possess predominantly spherical pores with smaller openings between the cells constitute a novel highly-conductive...
This paper is a follow-up of a hard disk drive study presented at ITherm 2006 on thermal-acoustic optimization of a HDD placed inside an air duct with an axial fan. Today we present a benchmark study performed on a number of consumer products containing a HDD. We will show that it is possible to predict if a certain application design is close to its optimal, set-level design. This is important for...
A heavily loaded cable management arm at the rear of a server system can have the visual appearance of presenting a significant obstruction to airflow. Tests were carried out to evaluate the level of airflow impedance presented by a fully cabled arm in a relatively low profile server system. This investigation reveals that airflow pressure drop due to the presence of the cable management arm is less...
In this paper we describe a novel cooling scheme utilizing a combination of fluidic (single-phase convection and phase change) and solid-state (superlattice cooler) techniques to simultaneously remove high background heat fluxes (~100 W/cm2) over the entire chip and dissipate ultra high heat fluxes (~0.5-1 kW/cm2) from multiple localized hotspots. This paper focuses on the conceptual design to assess...
Large density differences between liquid and vapor create buoyancy effects in the presence of a gravitational field. Such effects can play an important role in two-phase fluid flow and heat transfer, especially critical heat flux (CHF). CHF poses significant risk to electronic devices, and the ability to predict its magnitude is crucial to both the safety and reliability of these devices. Variations...
This investigation is an effort to demonstrate the feasibility of confined cell design for a phase change random access memory (Ovonic Unified Memory, OUM) cell which benefits, respectively, from the low current and the simple fabrication process of a line memory cell and T- structure. Similar to OUM devices, the confined cell design is also highly scalable. The 2-D numerical simulation results of...
In order to enhance measurement accuracy, a gas mass flow sensor integrated with micro channels is proposed in this paper. The uniqueness of this flow sensor is that there is thermal convection effect on two sides of diaphragm, which results in a more sensitive temperature distribution. The temperature characteristics of the novel flow sensor are simulated at different flow rates, and the optimization...
Convective heat transfer from a vertically stacked [3-D] electronic package (die-stacking) mounted in between two circuit boards is numerically investigated. Heat transfer characteristics of single chip packages and multiple-die packages for both two and four die stack are presented and compared. The package Reynolds number, based on the package height and upstream velocity, ranges from 150 to about...
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...
A wavelet-packet energy decomposition, and time frequency analysis based approach has been developed to monitor system-level damage in implantable biological electronic systems such as pacemakers and defibrillators. The approach focuses is on the pre-failure space and methodologies for quantification of failure in electronic equipment. Presented methodologies are applicable at the system-level for...
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...
Thermal performance of a high-power (>1 kW peak) automotive electronics module was evaluated using ANSYS' ICEPAKtrade Computational Fluid Dynamics (CFD) software. The module exchanges heat with cooling air via a plate-finned aluminum heat sink. To confirm the CFD model, the numerical air exit temperature results are compared to that of using the mass flow heat transfer equation. Additionally, convection...
A pressure atomized evaporative spray cooling nozzle array was used to thermally manage the power electronics of a 3 phase inverter module. The module tested was a COTS module manufactured by Semikron, Inc., and has a maximum DC power input of 180 kW (450 VDC and 400 A) with 25degC coolant. However, the standard heat sink that the module uses is a single phase liquid heat sink and when 100degC coolant...
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