Studies on resolution with ZEP530A for EUV mask

In this work, Zeon introduces the resolution with ZEP530A without PFAS restriction for dense L/S, iso-space and iso-line patterns on Si wafer by F7000S with VSB type in EB drawing equipment. Zeon examined litho-performance at dense L/S in changing 3 kinds of developers. The new developer of ZED-K90 (R&D sample) with lower both viscosity and solubility enabled to get lower roughness and enhance the resolution than those of ZED-N60 and N70 on LER although the dose to size was getting higher. There were some pinching defects on the patterns by ZED-N60 due to too strong solubility. On the other hand, ZED-N70 and K90 can be less on them due to the appropriate solubility. Next, litho-performance with ZEDK90 at iso-space and iso-line patterns was evaluated. The resolution was at design CD18nm in iso-line pattern and at design CD12nm in iso-space pattern and it was the best resolution among 3 developers. Additionally, the LER and SER with ZED-90 got lower than those with ZED-N70. It was clarified that the combination of ZEP530A and ZED-N90 had the sufficient potential to both enhance litho-performance including the resolution in EB resists and utilize them for EUV mask.