Two-dimensional sub-200 nm pitch Si gratings with natural orthogonality

As a standard for length and angle, two-dimensional (2D) grating reference materials can be used for performance verification and calibration of various microscopes and 2D stages. This paper proposes a 2D nanoscale reference grating manufactured by combining laser-focused atomic deposition (LFAD) and extreme ultraviolet interference lithography. The theoretical pitch of the 2D grating is 150.46 nm, which is only √2/2 times the pitch of the Cr grating manufactured by LFAD which can be traceable to the resonance transition frequency of Cr. Moreover, the angle between two periodic directions of the 2D nanograting has natural orthogonality. (author)