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

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.