Lithographic qualification of new opaque MoSi binary mask blank for the 32-nm node and beyond

摘要

We discuss the lithographic qualification of a new type of bi-nnary mask blank consisting of an opaque layer of MoSi on a glass sub-nstrate, referred to simply as OMOG. First, OMOG lithographic perfor-nmance will be compared to a previous chrome/MoSi/glass binarynintensity mask u0001BIMu0002 blank. Standard 70-nm chrome on class u0001COGu0002nwas not considered, as it failed to meet mask-making requirements.nTheory and a series of simulation and experimental studies show OMOGnto outperform BIM, particularly due to electromagnetic effects and opticalnproximity correction u0001OPCu0002 predictability concerns, as OMOG behavesnvery similarly to the ideal thin mask approximation u0001TMAu0002. A new TMA-npredictability metric is defined as a means to compare mask blanks. Wenweigh the relative advantages and disadvantages of OMOG comparednto 6% attenuated phase shifting. Although both mask blanks are likelynsufficient for the 32-nm and 22-nm nodes, some differences exist andnare described. Overall, however, of the blanks considered, it is con-ncluded that OMOG provides the most robust and extendable imagingnsolution available for 32-nm and beyond