Film thickness survey instrument and film thickness inspection manner

摘要

PROBLEM TO BE SOLVED: To visually inspect film thickness unevenness with high accuracy by improving the coherence between light rays reflected by the surfaces of a film and a substrate by projecting light having an intensity peak having a specific half-value width or smaller upon the substrate. ;SOLUTION: A light source section S the intensity peak of which has a half-value width of ≤30 nm, preferably, ≤20 nm, more preferably, ≤10 nm and the light intensity of which is not distributed in the other area than the peak wavelength area is used. It is also possible to narrow the half-value width of the intensity peak to ≤30 nm by using an optical filter 16 when the light source section S has an intensity peak having a half-value width of ≤30 nm. Since film thickness inspections are carried out visually, the light source section S is required to have illuminance of about that of a fluorescent lamp (300 lx). It is preferable, therefore, to use a light source section S containing two or more kinds of peak wavelengths, because the intensities of interfering light rays compensate the weakened intensities of the other light rays even when the angle of incidence to a semiconductor wafer 14 varies. Therefore, a slight film thickness difference can be detected sufficiently even when the eye position of an inspector and the film thickness difference arbitrarily change.;COPYRIGHT: (C)2000,JPO