Dariusz Klepacki

Nonlinear discrete elements in electro-thermal model of thick-film structure

The complexity of heat exchange mechanisms and difficulties in accurate determination of their coefficients make the thermal analysis a complicated problem at the beginning of the design process. In reality, only numerical calculations and specialized simulation programs can solve the systems of differential equations with very complicated boundary and initial conditions. The paper presents some aspects of describing of thermal model of the thick-film microcircuits with equivalent models (based on RC elements) which are used in temperature field simulation using PSPICE program

Modelling of Dynamic Temperature States in Layer Microelectronics Systems

The theoretical analysis (compared with experimental investigations) of dynamic temperature states in layer microcircuits (made in LTCC or HTCC technology) has been described in the paper. Two basic models and solution procedures of analytical equations system have been presented. Furthermore their basic advantages and disadvantages have been compared together with accuracy discussion. The solution of the analytical model (for the typical thick-film structure - active layer placed on alumina substrate) has been compared with the experimental results. The many factors which have influence on accuracy of obtained results have been taken into consideration and discussed. The results of analysis can be used in researches with reliability and tolerance aspect of microsystems (intensity of degradation processes) as well as in determination of thermal properties of the designed systems.

Simulation of transient thermal states in layered electronic microstructures

Abstract The analysis of dynamic temperature changes in microelectronic layered circuit (especially made in thick-film technology) has been presented in the paper. Such transient states are caused by electric pulse with high energy and short time of duration. It leads to short but the very violent temperature increase and – as result – defects or parameter changes of active layer. The mathematical function which describes the instantaneous temperature changes was presented in this paper in order to provide more accurate analysis of reliability and thermal properties measurement problems. The two-layer structures (with different thermo-physical properties) were the subject of conducted research, especially one of them, namely heat source excited by electric pulse. Such configuration is typical for microcircuits made in hybrid technology such as LTCC (low temperature co-fired ceramic), HTCC (high temperature co-fired ceramic) as well as thick – film technology in which polymer and photoimageable (photosensitive) materials are used.

Three Dimensional RC Model of Heat Transfer in Thick-Film Multilayer Structure

The complexity of heat exchange mechanisms in electronic circuits make the thermal analysis a complicated problem. In reality, only numerical calculations and specialized simulation programs can solve the systems of differential equations with very complicated boundary and initial conditions. The paper presents some aspects of describing of 3D thermal model of the thick-film multilayer structure with equivalent models (based on RC elements) which are used in temperature field simulation using PSPICE program.

High Energy Pulse Generator in Reliability Researches of Thick-Film Structures

In modern electronic microcircuits the intended and unintentional dynamic changes of the temperature (for example caused be electrical signals) are very often observed. The good knowledge about these phenomena is the basis of lifetime and reliability determination in the real-world operating conditions. The presented pulse generator is very useful in researches connected with such problems especially with reliability researches. It allows generating the high-energy pulses with short time duration. The special solution of the discharge circuit has been applied in the generator - it causes the precise realization of voltage and current measurements of the discharge pulse. Using of the microprocessor control system allows to introduce the additional functions which are very useful for users. Additionally, it is equipped in many constructional solutions, which are useful for different kinds of laboratory investigations.

Temperature field simulation of thick-film microcircuits using finite element method

Temperature field calculation is a very big problem in the case of small objects heated to the high temperature. In reality, the solving of heat transfer problem using analytical methods is impossible. At the present time, the numerical procedures applied in specialized simulation programs can solve the systems of differential equations with good accuracy. The paper presents some aspects of describing of thermal model of the thick-film microcircuits using finite element method. The example results of simulation (using ANSYS program) the resistive heater systems have been also included.

Influence of geometrical parameters of mutual parallel paths on process of disturbances propagation

The problems connected with electromagnetic couplings between mutual parallel paths in planar structures made in thick-film technology have been presented in the paper. The influence of geometrical configuration of thick-film path systems on shape of transfer function between them has been analyzed. The modification of transfer function under changes of the particular geometrical factors has been quantitatively determined using elaborated computer programs. The results of calculations have been presented for the selected path configurations.

Application of operational method in analysis of electromagnetic couplings in mutual coupled path systems of planar structures

The application of operational method for analysis of disturbances propagation process in frequency domain in mutual coupled path systems of planar structures has been presented in this paper. The suitable algorithms and their practical realizations in Mathcad program have been elaborated based on literature information. For verification of procedures the test circuits of conductive paths on ceramic substrates have been made in thick-film technology. The results of calculations and measurements (in time and frequency domain) have been presented for selected paths configuration.

Reliability of Operation of Single Chip Microprocessor with Watchdog in Thermal Stress Conditions

The temperature influence (especially their irregular distribution in the digital chip structure) on proper operation of the microprocessor system has been presented in the paper. As the results of non-uniform heating of silicon structure the incorrect operation of selected functional blocks of single chip microprocessor can be observed. Especially, the circuits which operation is independent on global clock of the whole logic structure are endangered on such phenomena. The good example can be block which controls the correctness of program running - its operation is dependent on correct working of independent internal generator. In reality (especially where temperature changes are sudden - e.g. turn on of microprocessor system) the systems of temperature correction does not operate properly and watching time is changed. As result the incorrect clearing signal can be generated.