Chemically Amplified Positive Resist for Acid Diffusion Control

The patent introduces a base polymer with specific functional groups (carboxylic acid groups, hydroxyl groups, or amine groups) as an intermediary substance that interacts with the photoacid generator to control acid diffusion. The base polymer acts as a buffer or trap for the generated acid, limiting its diffusion distance and preventing excessive acid spread that would degrade line-edge roughness, while still allowing sufficient acid to reach the intended pattern areas for high-resolution patterning.

The patent modifies the chemical parameters of the resist system by selecting specific base polymers with controlled functional group densities and types. By adjusting the concentration and nature of acid-reactive functional groups in the base polymer, the patent optimizes the balance between acid diffusion control (for low LER) and acid availability (for high resolution), effectively changing the chemical environment to resolve the contradiction.

The patent applies local quality by incorporating acid-reactive functional groups (carboxylic acid, hydroxyl, or amine groups) at specific locations within the polymer structure rather than uniformly throughout. The base polymer contains repeat units with these functional groups at controlled densities and distributions, allowing acid diffusion control where needed while maintaining overall polymer solubility in organic solvents. This localized functional group placement enables LER reduction without sacrificing manufacturability.

The patent creates a composite polymer structure combining hydrophobic backbone segments (for solubility in organic solvents) with hydrophilic functional group-containing segments (for acid diffusion control). This composite approach integrates two materials with complementary properties: the hydrophobic portions maintain solubility and processability, while the hydrophilic functional groups provide acid interaction capabilities for LER reduction.