Fabrication and characterisation of nanostructure step height sample

Step height calibration sample is a high-precision height (depth) standard transfer material for correcting the Z-axis characteristic parameter values of surface structure measuring instruments such as AFM, SEM and white light interferometer. It has the characteristics of accurate value transfer and small size structure. According to the traceability value of VLSI step height standard, step structure calibration samples with nominal height of 8 nm, 18 nm and 44 nm were fabricated by inductively coupled plasma (ICP) etching and lithography, and the height and surface roughness of the step structures are evaluated by AFM. The experimental results show that the standard deviation of the step height calculated by the algorithm is 0.820 nm, 0.770 nm, 1.786 nm, respectively. The upper surface roughness of the step structure was the surface roughness of the SiO2 film. The roughness of the bottom surface was related to the surface quality of SiO2 film, ICP etching process parameters.