Tuning Aluminum Precursors for Area-Selective Infiltration into Polymers for High-Precision Pattern Transfer

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Semiconductor industry faces challenges in nanoscale device fabrication due to resist limitations and patterning imprecision.
• Extreme ultraviolet (EUV) lithography, while enabling sub-10 nm features, is hindered by stochastic variations and overlay inaccuracies.
• Current resist materials exhibit limited etch selectivity and chemical stability, impacting reliable pattern transfer.

Purpose of the Study:

• To explore a novel pathway for high-precision patterning on monolayer polymer brushes.
• To investigate the use of area-selective deposition (ASD) combined with vapor phase infiltration (VPI) for creating thin metal oxide patterns.
• To enhance etch selectivity and pattern transfer performance in nanoscale fabrication.

Main Methods:

• Utilized area-selective vapor phase infiltration (AS-VPI) on patterned alternating regions of polypeptoid (PPd) and polystyrene (PS) monolayer brushes.
• Investigated the role of PPd as a growth promoter and PS as a deposition inhibitor in AS-VPI.
• Systematically studied the effects of precursor molecular size and ligand type using four aluminum (Al) precursors (TMA, TEA, TIBA, DMAI).

Main Results:

• AS-VPI achieved approximately fourfold greater AlOx formation on PPd compared to conventional atomic layer deposition (ALD).
• Precursor structure and ligand chemistry critically influenced infiltration selectivity through precursor-polymer interactions.
• Trimethylaluminum (TMA) showed high differentiation, yielding dense AlOx films on PPd, while bulkier precursors (TIBA, DMAI) exhibited limited infiltration.

Conclusions:

• Precursor-polymer interactions are key determinants of selectivity in AS-VPI.
• The developed AlOx films enable successful pattern transfer, presenting a viable bottom-up strategy for improved pattern transfer performance.
• This approach offers a promising solution for overcoming limitations in current nanoscale patterning techniques.