Patent ID: 7177019

Claim:
A method of fabricating a semiconductor wafer, the method comprising: (a) transferring a processed wafer from a wafer process station located within a process chamber to a metrology station also located within the process chamber, but spaced apart from the wafer process station, the metrology station containing a chuck for receiving and supporting the wafer and a measurement head for measuring the wafer, the wafer process station containing a transport system for supporting the wafer during processing by the wafer process station; (b) while the wafer is supported in the chuck of the metrology station (i) imaging a surface of the wafer with a camera in order to locate a selected measurement region of the surface containing at least one feature on the surface; (ii) directing a broadband light beam toward the measurement region; (iii) obtaining a first measurement of spectral content of the broadband light beam which has been reflected from the measurement region of the wafer; iv) obtaining a second measurement of spectral content of the broadband light beam which has not been reflected from the wafer; and (v) receiving the first and second measurements at a processor and evaluating the wafer based on the first and second measurements, where the second measurement is used to correct for system characteristics.