The effect of the geometric and thermal parameters on the thermal stresses during the passive cooling of printed circuit boards

The effect of components’ thermal properties in addition to their geometric configuration on the developed thermal stress in a model printed circuit board (PCB) is investigated. This effect is quantified through three parameters, the average normalized temperature gradient, maximum normalized temperature gradient and the uniformity factor. It is found that the effect of the geometric configuration, especially that of the heat-generating component, is more significant than the thermal properties of the components.

I. Introduction

During the design and manufacturing of printed circuit boards (PCBs) one of the main factors that has to be taken into consideration is the developed thermal stresses due to the heating of different components [1], [2]. Normally the stresses developed during the start-up phase is much smaller than the steady operation ones and they do not last long and it is the steady-state operation stresses that affect the components and the PCB lifetime, failure rates and performance [1], [3], [4].