Thickness Measurements of Silicon Dioxide Films Over Small Geometries

Abstract

A simple nondestructive interferometric technique to measure to thickness of transparent films on reflecting substrates in the range of 100–20 000 Å is described. Measurements can be made over areas as small as 0.1 mil in diameter. The method utilizes a microspectrophotometer, operating in the visible region of the spectrum, to measure the intensity of reflected light. The film thickness is calculated by one of two techniques depending upon whether the thickness is greater or less than 3000 Å. The error is less than 50 Å.