Amplitude and spatial frequency characterization of line edge roughness using CD-SEM

dIn this work we describe a simple and easy way to implement line edge roughness measurement using the Applied Materials VeraSEM_3D CD SEM. The outcomes of the measurement are the roughness amplitude and its main spatial wavelength components. In the first step we test this method on an e-beam resist wafer with known roughness and correlate the results with AFM measurements. In the second step, we measured the line roughness of a 193 nm resist FEM wafer. It was found that negative defocus is characterized by long wavelength components while positive defocus shows line roughness at all wavelengths.