摘要 |
A method of determining pattern evolution of a semiconductor wafer during chemical mechanical polishing prior to polishing end point by determining the periodic change in the variance and FT or FFT frequency spectra of shear force and change in variance and FT or FFT frequency spectra of COF, shear force and/or down force between the semiconductor wafer and the polishing pad. By comparing features of the data and spectra thus obtained, analysis leading to a deeper understanding of the changes that occur as CMP processes occur as well as diagnostic analysis of specific CMP processes and specific wafers can be accomplished
|