Negative resist operates through a chemical reaction triggered by exposure to light, electron beams, or X-rays. When exposed, the resist undergoes cross-linking, a process where the polymer chains in the resist form a network, rendering the exposed area insoluble. This cross-linking is often facilitated by a photo-initiator or sensitizer within the resist composition. After exposure, the substrate is developed, and the unexposed areas are washed away, leaving behind the desired pattern.
