Extreme ultraviolet lithography process and mask

摘要

An extreme ultraviolet lithography (EUVL) process is disclosed. The process comprises receiving a mask. The mask includes a low thermal expansion material (LTEM) substrate, a reflective multilayer (ML) over one surface of the LTEM substrate, a first region having a phase-shifting layer over the reflective ML, and a second region having no phase-shifting layer over the reflective ML. The EUVL process also comprises exposing the mask by a nearly on-axis illumination with partial coherence less than 0.3 to produce diffracted light and non-diffracted light, removing at least a portion of the non-diffracted light, and collecting and directing the diffracted light and the not removed non-diffracted light by a projection optics box (POB) to expose a target.

主权项

1. An extreme ultraviolet lithography (EUVL) process, comprising:
receiving a mask, the mask including:
a low thermal expansion material (LTEM) substrate;a reflective multilayer (ML) over one surface of the LTEM substrate;a first region having a phase-shifting layer over the reflective ML; anda second region having no phase-shifting layer over the reflective ML; exposing the mask by a nearly on-axis illumination with partial coherence σ less than 0.3 to produce diffracted light and non-diffracted light; removing at least a portion of the non-diffracted light; and collecting and directing the diffracted light and the not removed non-diffracted light by a projection optics box (POB) to expose a target.