Investigations to calibrate reference standards for the thickness of coatings

Investigations on the traceability of coating thickness measurements to the national standard of length were carried out by topographical and lateral methods. The topographical method used an interference-optical microscope a nd a modified scanning force microscope to measure the coating thickness as the height of a step on partially coated samples. For the lateral method, a scanning electron microscope was equipped with additional components to m easure the coating thickness on cross sections as the distance of material boundary lines. Standards with a coating thickness of about h = 10 nm to 50 mu m may be calibrated. The achievable uncertainty depended strongly on th e specimen preparation and the specimens themselves.