Thickness microscopy based on photothermal radiometry for the measurement of thin films

The photothermal detection technique is an innovative and non-contact method to investigate the properties of films on workpieces. This paper describes a novel experimental set-up for thickness microscopy based on photothermal radiometry. The correlation between the thermal wave signal and the film thickness is deduced and evaluated to determine the film thickness with a lateral resolution of less than 1 mm. Results indicate that the thickness microscopy is a useful method to characterize thin films and has the potential to be applied in-process.