Abstract: A method and apparatus for filtering a slurry used in a chemical mechanical polishing apparatus is disclosed. Magnets are provided along the piping network between a slurry reservoir and the CMP apparatus. A magnet may also be placed adjacent to the slurry reservoir to prevent iron oxide particles from traveling with the slurry to the CMP apparatus. The magnets attract iron oxide particles from the slurry and remove those particles from the slurry prior to polishing. This reduces the amount of defects caused by the iron oxide particles in the slurry.

Abstract: A method of monitoring the state of chemical-mechanical polishing that can be applied to the polishing of a metallic layer over a substrate. The method includes performing a series of scanning operations while a wafer is being polished to generate multiple reflectance line spectra in each polishing period. The degree of dispersion of the reflectance spectra is then utilized as a polishing index. In this invention, the standard deviation of the reflectance spectra in each period is used as a monitoring index, and the peak value of the standard deviation is used to determine the polishing end point. Surface uniformity is monitored by using the time interval between two time nodes at half the peak standard deviation values. When the distance of separation between the two time nodes is large, it means that the polished surface is not sufficiently flat.