SIMULTANEOUS MEASUREMENT OF THICKNESSES AND REFRACTIVE-INDEXES OF MULTIPLE LAYERS BY A LOW-COHERENCE CONFOCAL INTERFERENCE MICROSCOPE

We propose a novel technique for simultaneous measurement of layer thi cknesses and refractive indices of multiple layers. It is based on a c ombination of a confocal microscope and low-coherence interferometry. We derived an expression for the geometrical thickness and the refract ive index of each layer from both tracing of a marginal ray accepted b y a microscope objective and optical path matching conditions. Experim ental verification of this method is illustrated by several samples th at have a maximum of 13 layers. The geometrical thicknesses and refrac tive indices thus derived agreed well with those measured by a microme ter or cited from the literature. (C) 1996 Optical Society of America.