CROSS-TALK COMPENSATION IN EUV BASED METROLOGY WITH FINITE-SIZED TARGETS

摘要

A spectroscopic scatteromctry in the wavelength range of 10 nut - 20 nm (or wider wavelength range in the EUV or soft-x-ray spectral range) may be used primarily for overlay (OVL). as well as. critical dimension (CD) metrology. Bolh. the 0* order specular reflection, as well as. any higher-orders of diffraclion can be detected. In metrology, it would be desirable, to measure target-sizes of 4.5 μm~2. However, illumination spot-sizes, as produced with currently devised illumination optics, are usually larger than the target-size leading to crosstalk issues caused by product structures in the immediate neighbourhood of the metrology target.