Feasibility of Novel Rear-Side Mirage Deflection Method for Thermal Conductivity Measurements

Gwantaek Kim,Moojoong Kim,Hyunjung Kim

doi:10.3390/s21175971

Gwantaek Kim, Moojoong Kim + Show 1 more

Open Access

https://doi.org/10.3390/s21175971

Copy DOI

Abstract

Among the noncontact measurement technologies used to acquire thermal property information, those that use the photothermal effect are attracting attention. However, it is difficult to perform measurements for new materials with different optical and thermal properties, owing to limitations of existing thermal conductivity measurement methods using the photothermal effect. To address this problem, this study aimed to develop a rear-side mirage deflection method capable of measuring thermal conductivity regardless of the material characteristics based on the photothermal effect. A thin copper film (of 20 µm thickness) was formed on the surfaces of the target materials so that measurements could not be affected by the characteristics of the target materials. In addition, phase delay signals were acquired from the rear sides of the target materials to exclude the influence of the pump beam, which is a problem in existing thermal conductivity measurement methods that use the photothermal effect. To verify the feasibility of the proposed measurement technique, thermal conductivity was measured for copper, aluminum, and stainless steel samples with a 250 µm thickness. The results were compared with literature values and showed good agreement with relative errors equal to or less than 0.2%.

Highlights

With the development of different industries, many new materials have been developed and are being applied to various products, such as semiconductors, optical devices, MEMS devices, and displays
The setupThe forspecimen implementing theofrear-side mirage deflection is constructed as target material); the probe beam passes through the air layer beneath the specimen to avoid shown in Figure 2 to overcome the limitations of existing thermal property measurement mutual interference between the pump
Phase delay the results were derived according minationwere algorithm, it was necessary to the check whether experiment and theoretical analysis were conducted properly.through

Summary

Introduction

With the development of different industries, many new materials have been developed and are being applied to various products, such as semiconductors, optical devices, MEMS devices, and displays. The optimal thermal design of semiconductors is becoming difficult, owing to the miniaturization of the processes and diversification of the materials constituting electronic circuits [5]. Theory effect used in the proposed method is the phenomenon in which The photothermal Deflection. The setup for implementing the rear-side mirage deflection method is constructed as light energy is converted into thermal energy through the increased energy level on the shown in surface. Figure 2when to overcome the limitations of existing thermal property measurement material the photons of the pump beam collide with the material surface. The setupThe forspecimen implementing theofrear-side mirage deflection is constructed as target material); the probe beam passes through the air layer beneath the specimen to avoid shown in Figure 2 to overcome the limitations of existing thermal property measurement mutual interference between the pump.

Objectives

Methods

Results

Conclusion