A method for calibration of a substrate inspection tool is disclosed. The tool is used to inspect a standard substrate having simulated contamination defects with known characteristics. Performance of the tool in detecting the simulated contamination defects is determined. The tool exposes the standard substrate and simulated contamination defects to radiation having a wavelength of about 260 nanometers or less. The simulated contamination defects are stable over time under exposure to radiation having a wavelength of about 260 nanometers or less.