Measurement Of Thermal Conductivity Of Porous Low-k Materials

Low dielectric material is wide used in electron field .To increase the porosity is a effectual method to minish the dielectric constant of materials,but with the increase of the porosity,the thermal conductivity decreased which went against the elimination of heat. Tradeoff between thermal and electrical performance is important to consideration and at the same time, the determination of thermal conductivity is important .In this paper, We used 3ωmethod to determine the thermal conductivity of film material and used hot-wire-method(HWM) to measure the thermal conductivity of block material.1. Determine the thermal conductivity of film material by 3ωmethodDesign the apparatus electronic circuit based on the 3ωmethod which is facility and availability. In the electronic circuit ,We use MCU to control the DAC,which improve the accuracy of the adjuster. And to adapt to the multiple-module which generate a trinal sign used as referance for local-in-amplifer(LIA),the measurement is developmented.2. Determine the thermal conductivity of block material by hot-wire method.the thermal conductivity of low dielectric constant porous BN/SiCO material which is difficult to be made into the sample for traditional HWM,is determinated by developed hot-wire method. The result showed that with the increase of the porosity,the thermal condutivity is decreased from 4.4 W/Km to 2.4W/Km. The thermal conductivity of BN/SiCO material doped magnesium borate is increase markedly,but the dielectric constant increase too. The result shows that magnesium doped is available method to increase thermal conductivity,which still needed to be development.