Optical step height and trench depth measurement

Optical profilometer measurements are contact-free and fast. The depth of single high-aspect-ratio trenches and the step height of opaque materials can be measured. Deep trenches (50-225 μm) are measured with a white light interferometer. Shallower trenches and step height profiles are measured with a chromatic white light sensor. A vertical resolution of 6 nm and a lateral resolution of 2 μm make the optical profilometer well suited for larger structures on power semiconductors that are manufactured in the back end of line.