Impact of Use Conditions on Dielectric and Conductor Material Models for High-Speed Package Interconnects

Use conditions based on temperature and humidity can have a significant impact on the package material properties and loss, which is required to be included in modeling assumptions to be able to set realistic specifications. The dielectric loss is affected by both temperature and humidity through material properties. The conductor loss, however, is affected by only temperature explicitly through conductivity and implicitly through skin depth and surface roughness modeling. This paper presents a systematic use condition-dependent methodology for package high-speed interconnects including a robust dielectric material characterization metrology. Correlation to high fidelity insertion loss measurements at different temperatures indicates that the roughness correction factor extracted at one temperature does not fit all and leads to underestimating the loss at higher temperatures. Without loss of generality due to a unified form of correction factors of the existing common roughness models, a modified version of Huray's snowball model with an explicit temperature dependence is proposed to achieve highquality on-package interconnect loss correlation at different temperatures.