Much effort has been done to detect the defects of interest (DOI) by optical inspection systems because the size of the
DOI shrinks according to the design rule of a semiconductor device. Performance of the inspection system is dependent
on complicated optical conditions on illumination and collection systems including wavelength and polarization filter.
Magnitude of defect signal for a given optical condition was estimated using a simulation tool to find a suitable optical
condition and technologies required in the future. This tool, consisting of a near-field calculation using Finite Difference
Time Domain (FDTD) methods and an image formation calculation based on Fourier optics, is applicable not only to
Köhler illumination system but also to confocal system and dark field system. We investigated defect inspection methods
for the 45 nm and the next technology nodes. For inspection of various defects, the system using several wavelengths is
suitable. For inspection of a specific defect, the system with polarization control is suitable. Our calculation suggests that
the defect detection sensitivity for the 1X nm technology node should be increased by more than 10 times compared to
the 45 nm technology node.
Transient transmitted power through thin Si substrate (0.35 mm) irradiated with pulsed SHG-(532 nm) and fundamental (1064 nm) Nd:YAG lasers has been calculated to simulate laser marking process using FEM (finite element method). Dependence of attenuation factor on temperature and wavelength is considered. Fraction of transmitted power with a fundamental Nd:YAG laser drastically decreases by irradiation with three pulses from 40% to 5%, while the transmitted power with an SHG-Nd:YAG laser is negligible over the pulses.