Selenite-Directed Organotin-Oxo Macrocycles for Nanolithography

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• Designing organotin-oxo macrocycles for advanced nanofabrication with improved extreme ultraviolet (EUV) photon-harvesting and sub-50 nm resolution is a significant challenge.
• Traditional organotin-oxo systems face limitations in structural diversity and EUV absorption efficiency.

Purpose of the Study:

• To systematically design novel organotin-oxo macrocycles with enhanced EUV photon-harvesting capability and sub-50 nm lithographic resolution.
• To explore the use of selenite ligands in supramolecular assembly for creating polynuclear tin-oxygen clusters.

Main Methods:

• Synthesized a series of polynuclear ⁿbutyltin-oxygen macrocycles (Sn₈, Sn₁₂-α, Sn₁₂-β, and Sn₁₂Fe₁₈) using selenite ligand-driven supramolecular assembly.
• Evaluated the electron beam lithography (EBL) performance of the synthesized compounds, focusing on critical dimension resolution and sensitivity.
• Characterized the molecular architecture, film-forming ability, and surface roughness of the macrocycles.

Main Results:

• The Sn₁₂-α macrocycle exhibited outstanding EBL performance, achieving a 50 nm critical dimension resolution at a low dose of 50 µC·cm^-2.
• This performance is attributed to Sn₁₂-α's high Sn/Se content, compact 1.5 nm diameter, and excellent film-forming properties (0.59 nm surface roughness).
• Replacing carboxylate ligands with inorganic selenite overcame limitations in structural versatility and EUV absorption efficiency.

Conclusions:

• The study presents a novel approach to engineering metal-oxide photoresists by controlling cluster dimensionality through ligand-driven supramolecular assembly.
• The developed organotin-oxygen macrocycles offer a scalable pathway for high-sensitivity, high-resolution patterning in next-generation semiconductor manufacturing.
• This work establishes a new paradigm for designing advanced photoresists for nanofabrication.