Synthesis of End-Cap Enabled Self-Immolative Photoresists For Extreme Ultraviolet Lithography

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Conventional chemically amplified resists (CARs) utilize photoacid generators, leading to acid diffusion that compromises resolution, line edge roughness, and sensitivity (RLS). This RLS trade-off is a significant challenge in advanced lithography.
• Polyphthalaldehyde (PPA) derivatives offer self-immolative properties that can be leveraged to design novel resist systems.

Discussion:

• This study introduces end-cap enabled chain scissionable resists based on PPA derivatives for extreme ultraviolet (EUV) lithography.
• The self-immolative property of PPA is utilized to mitigate the acid diffusion issue inherent in CARs.
• Feasibility was confirmed through UV photodegradation experiments, demonstrating a new approach to resist design.

Key Insights:

• The developed PPA-based resist achieved a dose-to-clear (DTC) of 90 mJ/cm² under EUV radiation.
• This represents a significant improvement, over 100-fold, compared to previous PPA resist formulations.
• Density functional theory (DFT) calculations provided insights into the structural basis for the enhanced EUV sensitivity.

Outlook:

• This work presents a promising new class of resists for EUV lithography, potentially overcoming the RLS trade-off.
• Further research could optimize PPA derivatives for even higher sensitivity and resolution.
• The findings open avenues for designing next-generation lithographic materials with improved performance.