A flexible film thermocouple temperature sensor

TL;DR

This paper presents a flexible, miniature thin-film thermocouple sensor with optimized fabrication parameters, demonstrating high accuracy and fast response suitable for various temperature measurement applications.

Contribution

It introduces a novel flexible thin-film thermocouple with optimized sputtering conditions and a symmetrical electrode structure, enhancing performance and accuracy.

Findings

Potential difference error within 1°C during calibration

Optimal sputtering temperature identified at 100°C and 150°C

Adhesion strength of 9.4N confirmed

Abstract

This article introduces a thin-film thermocouple temperature sensor with symmetrical electrode structure. It uses PI film as a flexible substrate. Cu film and CuNi film made by MEMS manufacturing process as positive and negative electrodes. The device itself has the advantages of miniature, bendable and fast response speed. To reduce the film resistance value. Conducting metal film thickness and sputtering substrate temperature optimization experiments. The critical dimensions of Cu/CuNi film are 650nm and 400nm. The best sputtering substrate temperature for Cu/CuNi films is 100 degrees Celsius and 150 degrees Celsius. Testing the adhesion of thin film thermocouples using the peel-off method. The test result is 9.4N. Finally, the film thermocouple temperature sensor is subjected to a temperature static calibration experiment. The result shows that the actual potential difference error is within 1 degrees Celsius. It belongs to the second class standard in the formulation of thermocouple standards in my country. Through curve fitting, the corresponding relationship between temperature and potential difference is more accurate.