A silicon-based, sequential coat-and-etch process to fabricate nearly perfect substrate surfaces.

Area of Science:

• Materials Science
• Surface Engineering
• Nanotechnology

Background:

• Substrate imperfections like particles and pits are critical defects in thin-film applications.
• Existing ion beam thin film planarization processes effectively address particles but exacerbate pit defects.

Purpose of the Study:

• To develop a unified coat-and-etch process for simultaneous planarization of substrate particles and pits.
• To achieve sub-nanometer surface heights for advanced thin-film applications.

Main Methods:

• Developed a silicon-based coat-and-etch process.
• Utilized off-normal incidence etching combined with elements of normal incidence etching.
• Optimized the process to planarize ~70 nm particles and pits simultaneously.

Main Results:

• Achieved simultaneous planarization of ~70 nm substrate particles and pits to below 1 nm height.
• Significantly reduced high-spatial frequency roughness.
• Demonstrated a viable method for creating nearly perfect substrate surfaces.

Conclusions:

• The developed silicon-based coat-and-etch process effectively addresses both particle and pit defects.
• This technique is critical for enabling next-generation technologies such as extreme ultraviolet lithography masks.
• The process offers a significant advancement in substrate surface preparation for demanding thin-film applications.