EUVL Image Placement Error Analysis with a Rotatable Reticle - TIS and Overlay Results - (PPT)

摘要

In EUV lithography, non-telecentric illumination on the mask side causes extra overlay errors from any deviation of mask surface non-flatness. Distinguishing the overlay errors caused by mask non-flatness from others is the first step in efficiently mitigating them. The unique mask, which contains 468 transmission imaging sensor (TIS) marks, can be used to measure focus and X and Y offsets with the ADT. The mask can be loaded in all 4 different orientations on the ASML alpha demo tool (ADT). All mask registration errors, overlay errors from lens distortion, and mask/chuck non-flatness were investigated with this special mask.