METHOD OF MEASURING THE TOPOGRAPHY OF A SURFACE

摘要

This invention relates to a method of measuring the topography of a surface. According to this method a light source emits a substantially parallel bundle of light beams at a predetermined incident angle to the surface normal. A light of a first type, that is nonanalyzed as to its polarization or, alternately, polarized perpendicularly to the plane of incidence of the bundle of light beams to the surface, reflected from the surface is detected at an angle to said normal, which is substantially as big as the incident angle, and a light of a second type, that is polarized substantially parallel to the plane of incidence, reflected from the surface is detected. The quotient between the strength of light of the second type and the strength of light of the first type is formed to be a measure of the topography of the surface.