SUBMICRON METROLOGY IN THE SEMICONDUCTOR INDUSTRY

Techniques used to measure critical dimensions and overlay misregistration on integrated circuits during manufacturing are reviewed. The current needs for accuracy and reproducibility of these measurements in the semiconductor industry are discussed. The measurement capabilities of three types of instruments: electrical testers, scanning electron microscopes and sectioning optical microscopes are compared. Measurements made on sectioning optical microscopes are emphasized because of their ability to independently image different focus levels when making critical dimension measurements. A comparison of overlay measurements made with an electrical tester and a sectioning optical microscope is also presented.