High Accuracy Measuring Method for Thermal diffusivity in Thickness Direction in Thin Film Less Than 10 Micrometers

Thin polymer films are widely used as dielectrics in devices operating in the field of electrical engineering or power electronics, such as capacitors, and the thermal property of the films is of great importance for the heat dissipation of involved devices. Thermal diffusivity (D) is one of the crucial parameters concerned with heat conduction. The existing methods, however, have some difficulties in measuring thermal diffusivity of the thin film within 10 micrometers. In this study, a novel way based on thermal pulse method is proposed to measure thermal diffusivity. A step-shaped electric field is set within the two-layered sample composed of two identical films. The thermal response current is recorded after the sample partially absorbing the incident pulse. Based on the sample structure and the known parameters such as electrical field, electrode thickness and sample thickness, a multiparameters fitting is adopted to reconstruct the experimental current. The obtained thermal diffusivity is well consistent with the data in the literature.