Sequential Infiltration Synthesis into Maltoheptaose and Poly(styrene): Implications for Sub-10 nm Pattern Transfer

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Block copolymers (BCP) are used for pattern transfer via vapor phase infiltration.
• Carbohydrate-based high-χ BCPs enable sub-10 nm feature pattern transfer.
• Optimizing infiltrated material improves etch selectivity.

Purpose of the Study:

• Investigate semi-static sequential infiltration synthesis (SIS) of TMA and water into MH and PS-OH films.
• Optimize process parameters (temperature, pulse duration, exposure length) for SIS.
• Enhance etch selectivity for sub-10 nm pattern transfer using carbohydrate-based etch masks.

Main Methods:

• Sequential infiltration synthesis (SIS) of trimethyl aluminum (TMA) and water.
• Varying process parameters: temperature (64-100 °C), precursor pulse duration (10-75 ms TMA, 5-45 ms water), and exposure length (20-100 s).
• Characterization of infiltrated Al2O3 in maltoheptaose (MH) films.

Main Results:

• Decreasing exposure time from 100 to 20 s increased Al2O3 volume from 2% to 40% in MH, reducing infiltration depth.
• Temperature minimally affected infiltration degree between 64-100 °C.
• Both shorter (10 ms TMA/5 ms water) and longer (75 ms TMA/45 ms water) precursor pulses yielded 40% Al2O3 in MH.
• Demonstrated 12 nm pitch pattern transfer into silicon.

Conclusions:

• Optimized SIS parameters significantly increase alumina content in carbohydrate-based BCPs.
• Achieved high etch selectivity for sub-10 nm pattern transfer.
• Results advance understanding of SIS mechanisms and carbohydrate-based etch masks for nanoscale fabrication, relevant to the semiconductor industry.