Abstract A metrology chip for measurements of the diameters of a corpuscular ray is described. It uses a rotation moire for the metrology, which employs a very small rotation angle between the scanning direction and the edges used for the metrology. This rotation displays dimensions in x at a magnified scale in y with the magnification factor 1/(rotation angle in rad). The metrology chip is produced with high resolution electron beam lithography and metal lift-off for a pattern with high Z-contrast. The layout contains metrology bars in x- and y- orientation with sharp and straight edges. A calibration grid is placed with its bars perpendicular to the edges. Aside of the metrology edges cross marks are given to calibrate the scan direction, which is rotated with respect to the x- and y-edges by 1/200 rad. The accuracy obtained is in the nm-range and depends on the accuracy and straightness of the edge. Employing additive lithography using electron beam induced deposition allows to delineate edges with 0.8 nm edge roughness. The method described allows the evaluation of the diameter of the ray as well as the compensation of the present defocus and astigmatism of the beam forming system. The metrology and evaluation may be performed automatically.