Theoretical Analysis of Thermal Conductivity in Amorphous Inter-layer Dielectrics

Abstract

Understanding thermal conduction in interlayer dielectrics (ILDs) is important for the optimal design of interconnect layers in backend semiconductor processing for future highperformance nano-scale devices. Reduced thermal conductivity of porous ILDs for example can adversely affect the temperature rise in the embedded metal lines leading to un-desirable reliability issues and design constraints. In this paper, we report results of our theoretical and experimental investigation of thermal transport in amorphous and porous dielectrics. A phononhopping model has been adapted to calculate the thermal conductivity in disordered materials. The value of hopping integral has been calculated by comparing the modeling results with experimental data for various amorphous and porous materials. The model shows reasonable agreement with experimental data for various amorphous materials including SiO 2 and other glasses over a wide temperature range from 50K -300K. The model suggests that the hopping of localized high frequency phonons is a dominant thermal transport mechanism in such material systems.