A method and device for measuring the lateral thermal conductivity of a thin film

Abstract

The invention provides a method for measuring the transverse thermal conductivity of a thin film. Firstly, the 3ω method is used to measure the longitudinal thermal conductivity of the thin film to be measured by using the second metal strip deposited on the surface of the thin film to be measured as a heating source; There is a substrate; the longitudinal direction is the direction perpendicular to the film to be tested; then use the 3ω method, using the first metal strip as the heating source, to measure the temperature rise in the longitudinal direction of the film to be tested, and combine the measured longitudinal thermal conductivity to deduce The thermal power in the longitudinal direction of the film to be measured is obtained; the temperature rise of the first metal strip is measured at the same time, and the thermal field generated by the temperature rise of the first metal strip in the transverse direction of the film to be measured leads to the temperature rise of the second metal strip; finally calculated The transverse thermal conductivity of the film to be measured with thickness d. The invention adopts the "substrate / film to be tested / metal strip" sample structure, which effectively avoids the technical difficulties of preparing samples with a suspended structure; the bimetallic strip can accurately measure the lateral temperature difference of the film, and the measurement result has higher accuracy.

Description

technical field [0001] The invention belongs to the technical field of thermal physical property testing of thin film materials, and in particular relates to a method and a device for measuring the transverse thermal conductivity of thin films. Background technique [0002] Thermal conductivity is one of the important parameters to characterize the thermophysical properties of thin film materials. The thermal conductivity of the film material determines the ability of the film to conduct or insulate heat. For example, with the development of microelectronic devices towards higher integration, if the heat dissipation performance of microelectronic devices is not good, it will lead to local high temperature of the device unit, which will shorten the life of the device or even cause the device to break down. The higher the thermal conductivity, the higher the thermal conductivity The stronger it is, the better the heat dissipation capability; in addition, heat insulation mater...

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Problems solved by technology

Laser flash method (Measurement of thinfilm thermal conductivity using the laser flash method) requires laser heating and testing and involves the extraction of laser signals, so it requires precise optical circuits, and it is limited for multilayer films and thin films with large thickness. In addition, the flash method cannot directly test transparent materials; in the 3ω method, because the sample size is small, the radiation error can be effectively reduced by reducing the heat transfer area, and the test time is compared with the stable measurement method. It is shorter and increases the test speed, so the 3ω method is an important method for measuring the thermal conductivity of thin films. At present, there are also some methods for measuring the transverse thermal conductivity of thin films with the 3ω method, for example, Su Guoping’s paper (Thermal conductivity based on harmonic method The object of the anisotropic thermal conductivity measurement method in the experimental research on the thermal conductivity of functional materials is an anisotropic semi-infinite solid, so it cannot be applied to thin films with nanometer thickness; use the 3ω method to measure the suspended film structure sample (Phys.StatusSolidi A 210,No.1,106–118(2013)), it is impossible to accurately determine the transverse heat transfer distance of the film

In addition, the sample structure in the quasi-steady-state double-bridge method (Thermal conductivity measurement and interface thermal resistanceestimation using SiO2thin film) is somewhat similar to the structure mentioned in the present invention, but the quasi-steady-state double-bridge method is used for longitudinal thermal conductivity Rate measurement, and the error caused by multimeter measurement is large

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