Ellipsometric Method of Measuring the Height of Steps in Wafer Surfaces
Original Publication Date: 1978-Aug-01
Included in the Prior Art Database: 2005-Feb-21
To increase the resolution as well as the feasibility of known interferometric methods, the wafer to be tested is pressed by elastic means, for example, a rubber-clad, plane element, against a plane-parallel glass plate. Subsequently, the air gaps formed in the areas of grooves, as well as steps and other indentations between the glass plate and the wafer to be tested, are measured by ellipsometric methods in a known manner. In areas of contact between the wafer and the plane-parallel glass plate, the values psi(0) and delta(o), defining the phase shift and amplitude in conjunction with the optical reflection, are obtained.