Extreme Ultraviolet Lithography Process and Mask

An extreme ultraviolet lithography (EUVL) process, comprising:

• receiving a mask having a first region and a second region, wherein the phase difference between the first region and the second region is about 180 degrees and the reflectivity of the first region is more than 20% of the reflectivity of the second region;
• 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 more than 70% 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 semiconductor wafer.

A mask for extreme ultraviolet lithography (EUVL), comprising:

• a low thermal expansion material (LTEM) substrate;
• a reflective multilayer (ML) over one surface of the LTEM substrate;
• a conductive layer over an opposite surface of the LTEM substrate;
• a patterned phase-shifting layer over the reflective ML to define a first region and a second region, wherein the phase difference between the first region and the second region is about 180 degrees and the reflectivity of the region with the phase-shifting layer is more than 20% of the reflectivity of the region without the phase-shifting layer.