Method of monitoring the thickness of thin dielectric films and performance of the method.

摘要

The thickness of thin dielectric films covering metal surfaces can be measured while the surface and the film are in motion. This is accomplished by arranging a prism close to the moving film, passing plane polarized light into said prism so that it is totally internally reflected at the surface of the prism adjacent the film. Thereafter the angle of incidence is vaired to determine when surface plasma oscillations on the film-metal layer interface are generated. This is indicated by attenuation of the reflectivity. By measuring the reflectivity as a function of the angle of incidence, that angle of incidence which produces the minimum reflectivity can be determined and by comparing that angle of incidence to previously established standards, the film thickness can be determined.