Combined scanning force microscope and optical metrology tool

Abstract

An integrated scanning force microprobe and optical microscopy metrology system is disclosed, that measures the depth and width of a trench in a sample. The probe remains fixed while the sample is moved relative to the probe. The system detects the proximity of the probe to a sample and to the side walls of the trench, providing output signals indicating the vertical and transverse relationship of the probe to the sample. The system adjusts the relative position of the sample vertically and transversely as a function of the output signals. Variety of probes can be used with this system to detect the depth and width of the trench. The probe should have at least one protuberance extending down to sense the bottom of the trench. The tip of the probe can have Lateral protuberances that can extend in opposite directions (across the width of the trench) from the probe to detect the side walls of the trench. Forces on the protuberances are measured to determine the depth and the location of the side walls of the trench.