Approaching Angstrom-Scale Resolution in Lithography Using Low-Molecular-Mass Resists (<500 Da)

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Advanced semiconductor manufacturing relies on high-resolution patterning resists.
• Existing resists face a trade-off between resolution, line-width roughness, and sensitivity.
• Angstrom-scale patterning demands novel resist chemistries to overcome these limitations.

Purpose of the Study:

• To develop a new class of low-molecular-mass, metal-containing resists for high-resolution patterning.
• To investigate the mechanism of solubility switching in these novel resists.
• To demonstrate the performance of these resists in electron beam lithography (EBL) and extreme ultraviolet lithography (EUVL).

Main Methods:

• Design and synthesis of modular, low-molecular-mass ( <500 Da) metal-containing resists.
• Utilizing a two-component system: metal and a bonded radical initiator.
• Investigating the molecular and chemical processes during exposure via secondary electron generation and intramolecular rearrangement.
• Testing resist performance in high-resolution EBL and EUVL.

Main Results:

• Demonstrated record 1.9-2.0 nm isolated patterns and 7 nm half-pitch dense lines using EBL.
• Achieved 12 nm half-pitch line-space features with EUVL at 68 mJ/cm².
• Exhibited record low line-width roughness (≤2 nm) and a low Z factor (0.6 × 10^-8 mJ·nm³) in both EBL and EUVL.

Conclusions:

• Low-molecular-mass metal-containing resists offer a pathway to overcome traditional patterning trade-offs.
• The developed resist platform enables high resolution, low roughness, and high sensitivity for angstrom-scale lithography.
• Potential for unit-cell level patterning, paving the way for future semiconductor advancements.