The invention relates to the technical field of
semiconductor measurement, particularly provides a
system and a method for measuring a deep groove
etching structure in a 3D NAND, and aims to improve a traditional CD-SAXS measurement unit, design a
phase grating on a light path before probe light enters a measured sample, and measure the deep groove
etching structure in the 3D NAND based on a
Talbot effect and a fractional
Talbot effect. The distance between the
phase grating and a detected sample is designed to be a Talbot distance or a fraction Talbot distance, the
phase grating modulates the detection light, so that the
light intensity distribution of the detection light irradiated to the sample is in a light and dark stripe shape related to the
grating structure period and the duty ratio, and then through an alignment mechanism, the
light intensity distribution of the detection light irradiated to the sample is in the shape of light and dark stripes related to the
grating structure period and the duty ratio. According to the method, light fringes of an incident
light beam are aligned with a deep groove
etching structure region in the 3D NAND to be detected, and dark fringes are aligned with a memory hole structure region, so that the intensity of light entering the deep groove etching structure part is enhanced, the intensity of light entering the memory hole part is weakened, and the difficulty of extracting a deep groove nano-structure scattering
signal from a total scattering
signal is reduced.