Traditional lithography processes use resist materials that require organic solvents during the development step but also often contain components derived from PFASs (per- and polyfluoroalkyl substances), raising concerns about environmental pollution and sustainability. PFASs are difficult to degrade, and their long-term effects on ecosystems and human health are the subject of international concern, making the development of alternative technologies an urgent priority. Lithography is a fundamental technology with applications beyond semiconductor manufacturing, electronics, biomedicine, and microfluidic devices. Addressing its environmental impact remains critical in both academic and industrial contexts. This study introduces a water-developable positive photoresist derived from a polymeric material incorporating plant-derived sugar chains as the resist backbone. The reactivity of the material to ultraviolet irradiation, enabled by a photoacid generator, allows microfabrication through water development. Moreover, successful micrometer-scale patterning demonstrated a superior resolution compared to previous sugar-derived water-developable resists. The dextrin-based resist exhibited the highest performance, achieving a sensitivity of 150 mJ/cm2 and a resolution of 3.6 µm under an environmentally benign, PFAS-free process that enabled development with water. These findings propose a sustainable alternative to conventional petrochemical-derived photoresists, positioning it as a promising candidate for environmentally friendly photolithography processes.
Hachikubo et al. (Mon,) studied this question.