Patent ID: 7476556

Claim:
A method of processing a microfeature workpiece, comprising: generating a plasma in a chamber while a microfeature workpiece is positioned in the chamber; measuring optical emissions from the plasma; and determining a parameter of the plasma based on the measured optical emissions, wherein: measuring optical emissions from the plasma comprises (a) determining an intensity of the optical emissions at a plurality of discrete wavelengths from a first region of the plasma spaced apart from the microfeature workpiece by a first distance, and (b) determining an intensity of the optical emissions at the plurality of discrete wavelengths from a second region of the plasma spaced apart from the microfeature workpiece by a second distance different than the first distance; and determining the parameter of the plasma comprises (a) summing at least some of the determined intensities of the discrete wavelengths from the first region, and (b) summing at least some of the determined intensities of the discrete wavelengths from the second region.