METHOD FOR DETERMINING ANALYTICAL EQUATION OF FRINGE SCAN INTERFERENCE MEASUREMENT AND FRINGE SCAN INTERFEROMETER

摘要

PROBLEM TO BE SOLVED: To make the subject method applicable at the time of the analysis of fringe scan interference measurement exceeding a predetermined number of buckets as well by determining constants in a predetermined equation so as to minimize the error of a phase to be inspected caused by the error of the shift amount of a phase difference at the time of obtaining a phase to be inspected given by a surface to be inspected or an object to be inspected through the use of the predetermined equation. ;SOLUTION: The same beam is split into measuring light and reference light. The measuring light is reflected at a surface to be inspected, and then both beams are integrated to form interference fringes. The intensity data (g) of the interference fringes at each point at the surface to be inspected is measured, and measurement is which the phase difference between the measuring light and the reference light is shifted by π/2.j (j=0, ±1, ±2,..., ±n; n is a natural number) with respect to a reference state is performed 2n+1 times to measure the intensity data (g) of the interference fringes. Then at the time of obtaining a phase to be inspected θ given to the surface to be inspected by an equation, if we let the shift amount of the phase difference π/2.j have an error proportional to (j), constants Aj and Bj are determined so as to minimize the error of the phase to be inspected θ caused by the error of the shift amount. By this, application to the analysis of fringe scan interference measurement above 7 buckets is possible.;COPYRIGHT: (C)1999,JPO