In situ thickness determination of multilayered structures using single wavelength ellipsometry and reverse engineering

摘要

An in situ monitoring setup and process control loop were developed and integrated into a magnetron sputtering coater equipped with a Sentech SE 401 single wavelength ellipsometer, including the engineering of software for in situ process control to enhance production accuracy. By using that software, the system allows direct monitoring of the layer thickness on a moving substrate. It is shown that it is possible to determine the complex index of refraction from the distribution of measurements depending on the layer thickness. A strategy has been developed for in situ reverse thickness engineering of the top layers to compensate measurement errors.