Development of Water-Developable Negative Photoresist for i-Line Photolithography Using Cellulose Derivatives with Underlayer

Water-developable photoresist was synthesized by introducing methacrylate groups into hydroxypropyl cellulose (HPC), a cellulose derivative, via substitution of hydroxyl groups. The material enabled micropatterning through ultraviolet (UV) exposure at a wavelength of 365 nm with an exposure dose of 450 mJ/cm2. Line and dot micropatterns were formed on polypropylene substrates applying underlayer, achieving resolutions of 4.5 µm and 5.0 µm, respectively. The photoresist demonstrated superior etching resistance under CF4 plasma compared to another water-soluble photo resist. Unlike conventional photoresists that require hazardous organic solvents, this water-developable photoresist offers an environmentally friendly alternative, reducing health risks and environmental impact in the electronics industry.