Thermal conductivity study of porous low-k dielectric materials

An experimental method based on the 3 omega technique has been developed to measure thermal conductivity of porous Xerogel films as a function of poro sity. The results show that the thermal conductivity of these porous dielec tric films can be an order of magnitude smaller than that of SiO2. To accou nt for the porosity dependence of thermal conductivity, two porosity weight ed semiempirical models are introduced. These models suggest the scaling ru le expressing the thermal conductivity as a function of porosity. The decre ase observed in thermal conductivity of porous films suggests that the trad eoff between thermal and electrical performance is an important considerati on when implementing porous dielectric materials as interlevel dielectrics for on-chip interconnects. (C) 2000 American Institute of Physics. [S0003-6 951(00)00627-6].