Mechanism of temperature influence in thickness measurement using eddy current sensors

Eddy current technology is widely used in micro displacement measurement and conductor surface inspection due to its advantages of non-contact, non-destructive testing, and fast response speed. It also has excellent performance in thin film thickness measurement. However, in practical testing, due to the high sensitivity of eddy current sensors to changes in the thickness of nanoscale thin films, the measurement results are susceptible to temperature changes, leading to a decrease in measurement accuracy. This paper focuses on the issue of temperature stability in the measurement of copper film thickness using eddy current technology. Through the coupling simulation of electromagnetic and temperature fields combined with the analysis of temperature influence mechanism and formula derivation, the influence of temperature changes on the sense coil and copper film is revealed.