Recently, a research team from the Shanghai Institute of Optics and Fine Mechanics at the Chinese Academy of Sciences has achieved notable progress in the precise characterization of nanofilms through transmission electron microscopy (TEM). The team has developed a formula for calculating film thickness after tilting the sample along the β-direction. Additionally, they have introduced a method for accurately characterizing the structure of nanofilms using TEM. Using Mo/Si multilayer films as a case study, their research highlighted the importance of considering the crystal orientation of the Si substrate during TEM characterization. Alternatively, they suggested using amorphous substrate materials to ensure that the sample's cross-section remains perpendicular to the electron beam. This approach helps in avoiding artifacts that can arise from the two-dimensional projection imaging of three-dimensional samples. The team's proposed methods involve cutting Si wafers along specific directions and observing samples from specific zone axes, ensuring that the sample's cross-section aligns perpendicularly to the electron beam and thereby enhancing the accuracy of the characterization. The relevant findings have been published in Acta Optica Sinica.