Patent ID: 7042580

Claim:
A method of fabricating a semiconductor wafer, comprising the steps of: transferring a processed wafer from a wafer process station to a metrology station spaced apart but coupled to the process station, the metrology station containing a rotatable chuck for receiving and supporting the wafer and a translatable measurement head for measuring the wafer; imaging a surface of the wafer with a camera in order to locate a selected measurement region of the surface, the image being indicative of at least one feature on the surface; adjusting a position of an objective lens of the measurement head relative to the wafer to be aligned with the selected measurement region imaged by the camera, the translatable measurement head capable of translating the objective lens along a linear axis parallel to a plane of the surface of the wafer; directing a broadband light beam toward the wafer using an optical fiber coupling a light source to the translatable measurement head; obtaining a first measurement of spectral content of the broadband light beam which has been reflected from the wafer through the positioned objective lens; obtaining a second measurement of spectral content of the broadband light beam which has not been reflected from the wafer; and receiving the first and second measurements at a processor and evaluating the sample based on the first and second measurements, where the second measurement is used to correct for system characteristics.