Polarity-engineered Sn-Ti cluster photoresists for sub-10-nm high-resolution lithography

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• High-performance photoresists are critical for semiconductor manufacturing, particularly for sub-3-nm nodes.
• The conventional photoresist performance is limited by the trade-off between resolution (R), line edge roughness (L), and sensitivity (S).
• Simultaneously improving sensitivity and resolution has been a persistent challenge in photolithography.

Purpose of the Study:

• To overcome the RLS trade-off in photoresists.
• To develop a new strategy by enhancing the polarity of metal-oxo clusters.
• To synthesize and characterize novel tin-titanium (Sn-Ti) clusters for advanced lithography applications.

Main Methods:

• Synthesis of a series of Sn-Ti clusters with varying polarity by adjusting bridging ligands and reducing low-polarity ligands.
• Evaluation of photoresist performance using electron beam lithography (EBL) and extreme-ultraviolet lithography (EUVL).
• Analysis of the solubility-transition mechanism in cluster photoresists upon exposure.

Main Results:

• Higher polarity Sn-Ti clusters demonstrated enhanced sensitivity with decreasing developer polarity.
• The highest polarity cluster, TS-3, exhibited a significant polarity switch upon exposure.
• TS-3 enabled simultaneous improvement in sensitivity and resolution, breaking the conventional RLS trade-off.
• TS-3 achieved a minimum linewidth of 8 nm in both EBL and EUVL.

Conclusions:

• The study presents a novel approach to enhance photoresist performance by manipulating metal-oxo cluster polarity.
• The developed TS-3 cluster offers a pathway to break the RLS trade-off, enabling higher resolution and sensitivity.
• This work advances the understanding of solubility-transition mechanisms and provides a new avenue for high-performance photoresist development for next-generation semiconductor technology.