Rapid nondestructive method for measuring the refractive index and thickness of thin dielectric films

Refractive indices of dielectric films, measured by a modified Abeles method, are used for obtaining the film thickness by employing a new interferometric method based on polychromatic optical thickness fringes. Transparent films, ranging in thickness from a few hundred angstroms to a few micrometres, are suitable for measurement by the new technique with accuracies of about 1%. The relatively simple and inexpensive apparatus is amenable to computer control or other modes of automation, providing rapid and nondestructive measurements at a high rate of repetition. The new technique may, therefore, find extensive use not only in research laboratories, but also in industries based on thin film technology, especially in the field of microelectronics.