Thermal Analysis of the Ball Grid Array Packages
New quasi – 3D numerical model for thermal analysis of the BGA packages is presented. The general 3D heat transfer problem is correctly transformed to the set of 2D equations for temperature distributions in different layers of the package. The complexity and CPU time of the thermal analysis are many times reduced. The results of BGA package thermal modeling are presented.
System for thermal design on chip- and board-level of electronic components is introduced. It is integrated with Mentor Graphics CAD and consists of three subsystems: thermal design in IC Station; thermal design in Expedition PCB; thermal measurement for verification of temperature modeling results.
A new mathematical model of heat transfer in silicon field emission pointed cathode of small dimensions is constructed which permits taking its partial melting into account. This mathematical model is based on the phase field system, i.e., on a contemporary generalization of Stefan-type problems. The approach used by the authors is not purely mathematical but is based on the understanding of the solution structure (construction and study of asymptotic solutions) and computer calculations. The book presents an algorithm for numerical solution of the equations of the obtained mathematical model including its parallel implementation. The results of numerical simulation conclude the book.
The book is intended for specialists in the field of heat transfer and field emission processes and can be useful for senior students and postgraduates.
The monograph presents results by professor Dr. A. Shalumov’s Research School of Modeling, Information Technology and Automated Systems (Russia). The program, ASONIKA, developed by the school is reviewed here regarding reliability and quality of devices for simulation of electronics and chips during harmonic and random vibration, single and multiple impacts, linear acceleration and acoustic noise, and steady-state and transient thermal effects. Calculations are done for thermal stress during changes in temperature and power in time. Calculations are done for number of cycles to fatigue failure under mechanical loads as well as under cyclic thermal effects. Simulation results for reliability analysis are taken into account. Models, software interface, and simulation examples are presented.
For engineers and scientists involved in design automation of electronics.
The corrections of the methodology of power BJT and MOSFET transistor models parameter extraction taking into account the self heating effects are presented. For BJT these corrections are included into VBIC model parameter extraction process. For MOSFET current generator connected to standard SPICE MOS model is proposed to take into account drain current growth with transistor temperature.
This paper presents the results of mathematical modeling of heat transfer in the field emission process in a conic cathode of small dimensions with its possible melting considered. It is shown that the possibility of melting is determined by the cathode vertex angle. The melting is modeled in the framework of the phase field system using the proposed methods for the formation of the liquid phase zone.
The paper considers the technique of modeling of electronic reliability based on modeling electrical components environment temperature. As experience of the simulation and exploitation of electronic shows, one of the main factors that significantly affect the reliability characteristics is the thermal effect. This is confirmed by the statistics of a number of companies. In the paper for the simulation were used systems ASONIKA-K and ASONIKA-TM. On the example of a real electronic mean proved the need for a point temperature estimate for each electrical component and the account of these temperatures, instead of the average values in predicting the reliability indices. Such approach will significantly improve (20% -40%) the accuracy of estimates of the mean time to failure. Developed engineering method to predict reliability, built on the ”downward" hierarchical circuit simulation.
The computational model of the temperature sensors integrated on the IC chip with power transistors is developed. The 2D/3D problem of sensor placement is mathematically described by the classic heat transfer equation coupled with the equation for current density distribution. It is shown that parasitic effects of sensor current displacement and thermo-emf generation resulting from a temperature gradients (Seebeck effect) must be taken into account. For this purpose the special differential equation is introduced. The examples of point- and strip-like temperature sensors modeling for power BJTs and ICs are demonstrated.
Phenomenological model of temperature field evolution and effect of the relaxation processes caused by thermally activated defects and inertia of the medium on the thermal conductivity of solids under the action of intense energy flows is presented