High-accuracy surface measurement using laser-diode phase-stepping interferometry

The control of the surface quality of real objects such as machine's parts, layers, substrates, etc., is an important process during the manufacturing because of the high accuracy and precision, needed by the latest technologies. In this paper some results obtained by remote non-destructive method based on the phase-stepping interferometry with laser-diode are presented. With its ability for fast and accurate measurement this method allows surface profiling and fault detection with very high sensitivity and uncertainty better than lambda/100, The presented experimental results are obtained by CW operating single-frequency diode laser at a wavelength of 672 nm. The investigated objects are: 1. Point fault on nickel-plated aluminum substrates for magnetic disks used in the computer techniques. 2. Surface relief of selectively etched metal substrates for dielectric transparent layers. 3. Surface relief of mechanically printed rainbow hologram on cuprous layer. (C) 2000 Elsevier Science Ltd. All rights reserved.