Patent ID: 6739196
Filing Date: 2004-05-25
Classification: G01N

Abstract:
A non-destructive method for characterizing sputter target material, comprising the steps:a) obtaining a reference value for waveform phase inverting flaws and a reference value for waveform phase non-inverting flaws utilizing a reference sample; b) irradiating a test sample of said sputter target material sequentially with sonic energy at a plurality of positions along a surface of said test sample; c) detecting radio frequency echo waveforms induced by said sonic energy; d) discriminating texture-related backscattering noise from said echo waveforms to obtain a radio frequency echo waveform signal; e) monitoring said radio frequency echo waveform signal for 180Â° waveform phase inversion; f) comparing the radio frequency echo waveform signal associated with each of said plurality of positions with said waveform phase inverting reference value and said waveform phase non-inverting reference value and obtaining individual data points associated with a void-like flaw, a particle-like flaw and no-flaw; g) counting the data points associated with waveform phase inverting flaws, waveform phase non-inverting flaws, and no-flaws to determine a flaw count associated with waveform phase inversion flaws CFI, a flaw count associated with waveform phase non-inversion flaws CFN, a total flaw count CFT, and a total number of data points CDP; and h) calculating a total cleanliness factor FCT=(CFT/CDP)Ã—106, a cleanliness factor associated with phase inversion flaws FCI=(CFI/CDP)Ã—106 and a cleanliness factor associated with phase non-inversion flaws FC=(CFN/CDP)Ã—106.