Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
847282 | Optik - International Journal for Light and Electron Optics | 2012 | 6 Pages |
This paper describes an automated multiple-beam interferometry for measuring a calibrated step height of (27.00 ± 3.00) nm nominally. The fringes captured from the multiple-beam Fizeau–Tolansky interferometer were thinned by using a written program to obtain accurate measurement. We claim that multiple-beam interferometry based on automatic fringe thinning process can provide a real time solution for calibrating step heights precisely and with high accuracy. The uncertainty budget of the multiple-beam interferometry method due to incomplete parallelism of the incident beam and the inhomogeneity of the reflecting layers was calculated automatically with a written ray tracing program. The uncertainty budget in multiple-beam interferometry was estimated to be of the order of 3.00 nm.