Dry-Etching Processes for High-Aspect-Ratio Features with Sub-10 nm Resolution High-χ Block Copolymers

Area of Science:

• Materials Science
• Nanotechnology
• Plasma Etching

Background:

• Directed self-assembly of block copolymers (BCP) offers high-resolution nanostructure fabrication.
• Silicon-containing BCPs are promising for creating functional nanostructures.
• Dry-etching techniques are crucial for pattern transfer in nanolithography.

Purpose of the Study:

• To develop full dry-etching strategies for BCP nanolithography.
• To utilize an 18 nm pitch lamellar silicon-containing BCP for pattern transfer.
• To investigate different plasma chemistries for optimal pattern development.

Main Methods:

• Employed oxidizing Ar/O2 and nonoxidizing H2/N2 plasmas for topcoat removal.
• Investigated etch-stop layer formation and breakthrough plasma requirements.
• Optimized He/N2/O2 plasma chemistry for smoother mask formation.
• Successfully transferred patterns into silicon, silicon-on-insulator, and silicon nitride.

Main Results:

• Identified an interfacial layer under Ar/O2 plasma requiring additional etching steps.
• Demonstrated that H2/N2 plasma avoids the interfacial layer.
• Showcased improved lamellar modification and mask regularity with increasing H2/N2 ratio.
• Achieved successful pattern transfer into diverse hard-mask substrates.

Conclusions:

• Developed effective dry-etching strategies for silicon-containing BCP nanolithography.
• Highlighted the 18 nm pitch BCP's capability for patterning hard masks.
• Demonstrated the versatility of this technique for microelectronic applications.