Printability of extreme ultraviolet lithography mask pattern defects for 22-40 nm half-pitch features

Assessing the printability of EUV (extreme ultraviolet) lithography mask pattern defects is critical for determining EUV mask patterning, defect metrology, and repair technology requirements. Printability of mask defects at the wafer level depends on defect size, defect shape, defect location, and the line width and pitch of the structure being printed. Earlier reports showed the relationship between the defect size on the mask and the printed critical dimension for 40-70 nm dense lines(1). Improvements in the EUVL process now enable assessment of mask pattern defect printability for 22-40 nm half-pitch features. We report here the smallest mask pattern defects that printed at different locations in 22-40 nm structures using the Intel Micro-Exposure Tool (MET). Various types of defects such as indentations or protrusions were purposely incorporated into features on an EUV mask. The sizes of the patterned defects on the mask were drawn between 10-250 nm (= 2-50 nm on the wafer). The minimum printable defect size varied by over 100 nm, depending on the defect shape and location.