Measurement of the anisotropic thermal conductivity in polymer

摘要

Polymer films of thickness near 1 micrometer are serving as passivation in propose high-speed logic circuits and as active regions in novel electronic and optoelectronic devices.The thermal conductivities of these films may be highly anisotropic due to the partial orientation of moelecular strands.This work develops a technique for measuring the vertical and lateral thermal conductivities of polyimide layers of thickness between 0.5 and 2.5 micrometers.The vertical conductivity is isolated using Joule heating and electrical-resistance thermometry in a mesa structure made from an aluminum/silicon-nitride/polymer/aluminum stack on a siliconsubstrate.Data for the same films without the mesa geometry are influence by the lateral conductivity,which is determined to be larger by approximately a factor of six.The approach developed here is compatible with IC fabrication technology and applicable to a broad variety of novel organic dielectric films.