Oxide thickness measured by ellipsometer

• a laser beam is reflected by the wafer placed on the round support seen in the picture
• in the right part, a detector receives the reflected beam and analyses it
• from the phase shift, the refractive index and the film thickness can be calculated and presented on the screen in the right corner
• it works only for transparent films, and not very thin, an aproximate value of the thickness has to be given at the beginning