OPTICAL METROLOGY OF A STRUCTURE FORMED ON A SEMICONDUCTOR WAFER USING OPTICAL PULSES

摘要

A structure formed on a wafer can be examined by directing an incident pulse at the structure, the incident pulse being a sub-picosecond optical pulse. A diffraction pulse resulting from the incident pulse diffracting from the structure is measured. A characteristic of the profile of the structure is then determined based on the measured diffraction pulse.