Inspection of a lithographic mask that is protected by a pellicle

摘要

A system and a method for evaluating a lithography mask, the system may include: (a) electron optics for directing primary electrons towards a pellicle that is positioned between the electron optics and the lithography mask; wherein the primary electrons exhibit an energy level that allows the primary electrons to pass through the pellicle and to impinge on the lithographic mask; (b) at least one detector for detecting detected emitted electrons and for generating detection signals; wherein detected emitted electrons are generated as a result of an impingement of the primary electrons on the lithographic mask; and (c) a processor for processing the detection signals to provide information about the lithography mask.

主权项

1. A method for evaluating a lithography mask, the method comprises:
directing, by electron optics, primary electrons towards a pellicle that is positioned between the electron optics and the lithography mask; wherein the primary electrons exhibit an energy level that allows the primary electrons to pass through the pellicle and to impinge on the lithography mask; detecting, by at least one detector, detected emitted electrons and generating detection signals; wherein detected emitted electrons are backscattered electrons generated as a result of an impingement of the primary electrons on the lithography mask; masking, by a filter, secondary electrons from detection by the at least one detector, the secondary electrons emitted from the pellicle due to an interaction of the backscattered electrons with the pellicle; and processing, by a processor, the detection signals to provide information about the lithography mask.