Control electrically conductive of thin films by using subminiature eddy current transducers

Abstract

The research objective was the development of subminiature eddy-current transducer designed for studying thin films. Timeliness is subject to the need to assess and predict safe operation life of products manufactured using thin films. A review of various methods for thin films studying was made, including the eddy-current method, based on an analysis of the interaction of an external electromagnetic field with the electromagnetic field of eddy currents induced by an energizing winding in an electrically conductive film. A subminiature surface eddy-current transducer of the transformer type was developed. On the basis of eddy-current transducer, a software and hardware complex was developed to control the eddy-current transducer (to generate alternating current of various frequencies, to provide its supply to the eddy-current transducer, to receive a useful signal from transducers to ensure its convenient visualization). The hardware and software complex provided the opportunity to make local studies of the electrical conductivity of non-ferromagnetic thin films by the method of eddy currents. In the course of the study it was possible to develop an algorithm for finding changes in the average amplitude of the output signal, which allows to conclude about the electrical conductivity of the thin film. The study of thin film samples using the developed measuring system is conducted. The results of testing of Al, Ag and Ni films were presented, and the electrical conductivity values of the samples were obtained.