System and method for fabricating metrology targets oriented with an angle rotated with respect to device features

摘要

A lithography system includes an illumination source including two illumination poles separated along a first direction and symmetrically distributed around an optical axis, a pattern mask to receive illumination from the illumination source, and a set of projection optics to generate an image corresponding to the pattern mask onto a sample. The pattern mask includes a metrology target pattern mask and device pattern mask elements. The device pattern mask elements are distributed along the first direction with a device separation distance. The metrology target pattern mask includes a set of metrology target pattern mask elements having a diffraction pattern corresponding to that of the device pattern mask elements. A metrology target generated on the sample associated with the metrology target pattern mask is characterizable along a second direction and has printing characteristics corresponding to those of device pattern elements generated on the sample associated with the device pattern mask elements.