Thermo-Mechanical load Influence on Electronics Packages

Abstract

This paper proposes the simulation-based behavioral study of electronic components of a DC-DC converter for thermo-mechanical loads to build more reliable electronic products. It is asserted that temperature management plays a vital role in any electronics packages for their better performance and hence when these packages are subjected to structural loads at an elevated temperature, the resulting thermal strain and stresses may lead these products to failure. This is because the parts used to build these products will have different coefficients of thermal expansion (CTE). When these parts with different CTE are assembled, thermal stress will develop at the interface due to variation in temperature which influences the material properties of the assembled parts and leads to damage.In this work, the conduction mode of heat transfer analysis is performed for the convertor that possess a heat load of l8.5w, which is distributed over two PCBAs comprising of four exclusive thermal layers having 70micron meter of copper. To enhance the accuracy of analysis results, contact conductance is defined between PCBs & housing and through PCB and components. The base of the converter is maintained at 75deg C.The thermo-mechanical analysis is performed using the finite element method by modeling mechanical parts and critical electronic components by defining definite material properties. The analysis is performed with a structural static gravity load of 25g, and temperature results are imported from the thermal analysis. The converter is constrained in all degrees of freedom at the mounting locations. This paper explains the details of extensive work conducted using simulation software to predict the effect of thermo-mechanical loads on critical electronic components, component leads and other critical parts of the converter. The measures considered to avoid damage encounters due to high temperatures and thermal stress are also covered.