Low temperature thermal conductivity measurement method

A measurement method and technology of thermal conductivity, which is applied in the field of measurement of thermal conductivity of solid materials, can solve problems such as weak triple frequency voltage signal, inaccurate measured value of thermal conductivity of thin film, small temperature coefficient of resistance of metal conductor wire, etc. Achieve the effect of improving measurement accuracy, improving measurement accuracy and effectiveness, and avoiding deviation of measurement values

Inactive Publication Date: 2016-01-13
PEKING UNIV
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Problems solved by technology

However, the existing 3ω method has the following disadvantages: when measuring the thermal conductivity of the film, the boundary thermal resistance on the interface between the film and the substrate cannot be deducted, which makes the measured value of the thermal conductivity of the film inaccurate; The temperature coefficient of resistance is small, and the triple frequency voltage signal is too weak, which makes the system unable to perform effective measurement at extremely low temperature (<20K)

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Embodiment Construction

[0032] The concrete implementation method of the present invention is as follows. It is mainly divided into two parts: device fabrication and data measurement. The following is the implementation steps of a typical measurement example.

[0033] 1. Device fabrication

[0034] 1) Sample acquisition: the sample material is prepared or cut into rectangular slices with a size of 5 mm×7 mm, and a thickness of about 0.4-0.6 mm.

[0035] 2) Surface cleaning: put the sample into analytical pure trichlorethylene for 5 minutes, ultrasonic cleaning in analytical pure acetone for 5 minutes, ultrasonic cleaning in analytical pure isopropanol for 5 minutes, and blow dry with high-purity nitrogen.

[0036] 3) Drying: The sample is baked on a hot plate at 100-200°C for 10-30 minutes.

[0037] 4) Glue rejection 1: Place the sample on a glue rejection table, add 1-2 drops of MicroChemPMGISF6 photoresist on the surface, and shake the glue at 4000r / min for 60s.

[0038] 5) Baking 1: Baking on ...

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Abstract

The invention relates to a low temperature thermal conductivity measurement method. The method can be used for measuring the thermal conductivity of a solid substrate or a film at normal temperature or a low temperature. The method is a 3omega method based on solid material thermal conductivity measurement, and is improved from the following aspects: the thickness of a film on a substrate is changed, measurement is carried out multiple times, and the vertical thermal conductivity of the film is obtained through a difference technology, so the measured value deviation caused by boundary thermal resistance on a film and substrate interface is effectively avoided; a preamplifier with extremely low linear deflection is arranged in front a lock-in amplifier for measurement, and amplifies a signal 10 times, so the measurement precision is effectively improved; the amplification factor of the preamplifier is adjusted through a one-chip microcomputer control digital potentiometer, so fully-automatic measurement is realized; and a measurement warm area is expanded to extremely low temperature by adopting magnetic material permalloy.

Description

technical field [0001] The invention relates to a method for measuring the thermal conductivity of a solid material, in particular to a method for measuring the thermal conductivity of a solid substrate or thin film at normal temperature or low temperature. Background technique [0002] The 3ω method is a method for measuring the thermal conductivity of a solid substrate or thin film. (Thermal conductivity measurement from 30 to 750K: the 3ω method, Cahill, David G., Review of Scientific Instruments, 61, 802-808 (1990)) The low-temperature thermal conductivity measurement method according to the present invention is based on the 3ω method. [0003] The measurement principle of the 3ω method is: place a thin conductor wire on the surface of a solid dielectric material, apply a sinusoidal alternating current to the conductor wire through an external circuit, and measure the voltage signal at both ends of the conductor wire. Since the alternating current generates heating powe...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N25/20
Inventor 熊林黄河清林熙
Owner PEKING UNIV
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