The development of environmentally friendly materials and processes is a major issue that concerns all industrial sectors, including microelectronics. The aim of this study is to demonstrate the possibility of using chitosan-based photoresists for microelectronic applications on silicon by 193 nm photolithography. The photopatterning of chitosan films is demonstrated and analyzed by different spectroscopy and microscopy techniques. In particular, it is shown that 193 nm irradiation allows one to induce chain breaks that modify the solubility of chitosan in an aqueous developing solution, without denaturing the chitosan macromolecule chains. This mechanism allows one to obtain patterns, and it is shown that these patterns can be transferred by physical etching into silica. It is also demonstrated that the formulated resins are compatible with industrial spin-coating and exposure tools, which opens very interesting perspectives for these chitosan-based positive resins in a microelectronic context.

Photolithography is a core part in microelectronic processes. This technological step implies the use of numerous hazardous carcinogenic compounds in the formulations, the use of solvents for processing synthetic polymers to obtain micro and nanostructures. We proposed the use of chitosan-based biosourced water-soluble resins to significantly reduce the environmental impact

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.