Chitosan as a water-based photoresist for DUV lithography

DUV photolithography, as the major process of nanofabrication, typically requires high volumes of toxic chemicals within resist formulation, solvent and developer. In this context, alternative chemistries to current petroleum-derived photoresists are proposed to reduce environmental impacts. Chitosan represents a bio-sourced resist allowing water-based patterning processes free of organic solvent and alkali-based developers, by substitution with a green solvent (deionized (DI) water). This paper present last stepwise process in the patterning integration with a chitosan-based resist. Preliminary results using a 300 mm pilot line scale at CEA-Leti demonstrate patterns resolution down to 800 nm along with plasma etch transfer into Si substrate. Finally, the environmental impact through life cycle analysis (LCA) of the whole process based on chitosan resist is assessed and compared to conventional solvent-based processes.