Measuring the Thickness of Metal Films: A Selection Guide to the Most Suitable Technique

Abstract

The determination of thickness has a fundamental importance in all fields in which the implementation of films and coatings are required and takes a crucial role in the electroplating sector. The thickness influences many aspects of the coatings such as electrical, mechanical, corrosion protection, and even aesthetic properties. In the multitude of applications of thin layer coatings, the variability of thicknesses and materials is very high, as well as the variability of possible techniques that can be used to determine the characteristics of the layers of interest. The first distinction that can be made between these techniques is that which divides destructive techniques from non-destructive ones, in which, however, the semi- or micro-destructive techniques are immediately difficult to place. Other important parameters to consider are the cost, both for the purchase of the instrumentation and for each single analysis, the difficulties in preparing and measuring the sample, data processing, and obviously the detectable thickness ranges, the possible measurable materials, and precision and accuracy. The purpose of this work is to compare the characteristics of the various investigation methods, with a particular focus on metal film applications, so that it will be easier to choose the most suitable technique for each purpose.

Eddy Current Method for Studying Inhomogeneities and Defects in Thin Metal Films

“…To determine the characteristics of thin metal films, the following non-destructive research methods are widely used: atomic force microscopy, scanning electron microscopy, X-ray diffractometry, spectroscopic ellipsometry, four-probe method, eddy current method [6][7][8].…”

Method for Film Thickness Mapping with an Astigmatic Optical Profilometer

“…Moreover, noncontact methods avoid the damage to the sample that results from the interaction force between the sample and probe, as occurs with contact methods. The appropriate measurement method depends on the requirements of the application [16]. For instance, spectroscopic ellipsometry (SE) is commonly used for measuring transparent films with thicknesses ranging from nanometers to tens of micrometers [17][18][19].…”

Quantitative and Qualitative Characterization of Coatings Added to Low Voltage Switches

“…These require the implementation of transverse cuts at the level of the conductor to be diagnosed. Then, the sections are analyzed using an optical system (optical microscope or scanning electron microscope) to obtain the appropriate magnification to determine the nature and thickness of coatings [18].…”