Development of EUV scatterometer with high-harmonic-generation EUV source for nano-scale grating measurement

摘要

We have developed a EUV scatterometer using a focused high-order harmonic generation (HHG) source for nano-scale grating measurement. The coherent light source with multiple discrete wavelengths of 25-35 nm was pumped by a tabletop Ti:sapphire laser system. A charge-couple-device (CCD) camera directly records the diffraction image of the zero and the first order diffraction information from the grating samples. The grating structure can be reconstructed base on the calculations from the location and the intensity distribution of diffraction pattern.