Photoacid Generating Polymer Urethane Linkage Lithography

The patent introduces a polymer backbone as an intermediary structure to which photoacid generator groups are covalently bound. This polymer mediator holds the acid-generating groups in a fixed spatial arrangement, preventing free diffusion of acid while maintaining the catalytic amplification effect. The polymer acts as a stationary scaffold that enables chemical amplification without the harmful side effect of acid migration, thereby resolving the contradiction between achieving high sensitivity and avoiding image blur.

The patent segments the photoresist system into distinct functional modules: acid-sensitive groups attached to polymer chains, photoacid generator groups covalently bound to the polymer backbone, and base soluble groups. This segmentation allows each component to perform its specific function independently. The acid-sensitive groups remain protected during storage and processing, while the covalently bound PAG groups generate acid in situ without diffusing, as they are fixed to the polymer segments. This modular segmentation resolves the contradiction between maintaining solubility stability and preventing acid diffusion.

The patent implements a self-service mechanism where the polymer structure itself provides the containment field for the photoacid generator groups. Each polymer chain serves as its own acid containment vessel, with PAG groups covalently bound and unable to diffuse beyond the polymer chain boundaries. This self-contained architecture eliminates the need for external barriers against thermal diffusion, enabling precise patterning at sub-50 nm feature sizes without image blur from acid migration.