Temperature and moisture dependence of PCB and package traces and the impact on signal performance

As link speeds continue to increase and operating margins are in the tens of millivolts and picoseconds, many engineers have lingering questions about the robustness of their links when one considers manufacturing, material, and temperature variation. Most hardware systems are required to reliably operate over a wide range of environmental conditions. In this paper, we examine the impact of temperature and humidity variation on the electrical properties of typical printed circuit boards traces (PCBs) and organic package traces. Test structures will be measured and the temperature-dependent, dielectric material properties, Dk(T, f) and Df(T, f), will be extracted for organic packaging materials and several PCB materials. By using two different methods, the extracted dielectric material properties can be compared and the dielectric component of loss can be isolated from the conductive loss. With the added dimension of temperature as an input parameter in our simulation environment, a temperature dependent multi-pole Debye model will be introduced to capture the dependence of the s-parameters on temperature.