Sub-32nm patterning using EUVL at ASET

Since device makers must use the lowest cost process for their survivals, they will want to use their old refractive litho-tools such as ArF and KrF. They will want to extend their refractive optical paradigm by using the immersion lithography. However, simulation results show that it is difficult or impossible to print sub-30nm patterns using immersion without resolution enhancing techniques, for example, double exposure. Therefore EUV is a promising candidate to prepare the next generation litho-technique. ASET is focusing all efforts on developing EUV mask and EUV resists. In this paper, we have focused on and evaluated resists for EUV lithography targeting sub-30nm patterning. The resists we evaluated were mainly chemically amplified resist for KrF and ArF and new type of resist for EUV. And we also tuned resists with solution and additives. We also checked several properties such as LWR (Line Width Roughness), minimum resolutions, and sensitivity curves. Several candidates have shown potentialities for EUV resists. In present, EUV resist is not perfect and has unsolved problems such as outgassing and low speed, but it will be also improved as soon as ArF and KrF have been done.