Patent Document ID: 20070061088
Application ID: 11554716
Patent Status: 0

Claim One:
1. A method of detecting a delamination defect in a chemical mechanical planarization process, the method comprising the steps of: sampling an acoustic emission signal of the chemical mechanical planarization process; identifying the dyadic length of the sampled acoustic emission signal; determining a maximum level of wavelet decomposition based on the dyadic length of the sampled acoustic emission signal; identifying a plurality of levels of decomposition up to the maximum level of decomposition; wavelet decomposing the sampled acoustic emission signal at each of the plurality of levels of decomposition up to the maximum level of decomposition to obtain a plurality of wavelet coefficients; identifying an energy content for each of the plurality of wavelet coefficients at each of the plurality of levels of decomposition; testing the energy content of the plurality of wavelet coefficients at each level of decomposition to identify a plurality of decomposition levels with significant wavelet coefficients having a significant energy content; thresholding the plurality of significant wavelet coefficients at the decomposition levels with significant wavelet coefficients having a significant energy content to identify a plurality of thresholded significant wavelet coefficients; reconstructing the detail signal in a time domain from each of the plurality of thresholded significant wavelet coefficients; and observing the reconstructed detail signals to detect a delamination defect in the chemical mechanical planarization process.