Extreme Ultraviolet Lithography Process and Mask

摘要

A process of an extreme ultraviolet lithography (EUVL) is disclosed. The process includes receiving an extreme ultraviolet (EUV) mask with multiple states. These different states of the EUV mask are assigned to adjacent polygons and adjacent assist polygons. The EUV mask is exposed by a nearly on-axis illumination (ONI) with partial coherence σ less than 0.3 to produce diffracted lights and non-diffracted lights. Most of the non-diffracted lights reflected from main polygons and reflected lights from assist polygons are removed. The diffracted lights and the not removed non-diffracted lights reflected from main polygons are collected and directed to expose a target by a projection optics box.

主权项

1. An extreme ultraviolet lithography (EUVL) process, comprising:
receiving an extreme ultraviolet (EUV) mask with multiple states, wherein different states of the EUV mask are assigned to adjacent polygons and adjacent assist polygons; exposing the EUV mask by an on-axis illumination (ONI) with partial coherence σ less than 0.3 to produce diffracted lights and non-diffracted lights; removing a majority of non-diffracted lights reflected from the main polygons; removing a majority of diffracted and non-diffracted lights from the assist polygons; and collecting and directing the diffracted lights and the not-removed non-diffracted lights from main polygons by a projection optics box (POB) to expose a target.