Electron beam lithography with feedback using in situ self-developed resist.

Area of Science:

• Materials Science
• Nanotechnology
• Physics

Background:

• Conventional electron beam lithography (EBL) is an open-loop process lacking real-time feedback.
• Post-exposure resist development prevents in-process adjustments for beam distortions, limiting resolution and uniformity.

Purpose of the Study:

• To introduce a self-developing nitrocellulose resist for in situ feedback in EBL.
• To demonstrate the optimization of electron beam parameters using this feedback mechanism.
• To achieve enhanced resolution and uniformity in EBL patterns.

Main Methods:

• Utilizing self-developing nitrocellulose resist for immediate pattern visualization post-exposure.
• Performing in situ high-magnification examination of exposed patterns.
• Iteratively adjusting electron beam parameters, specifically working distance, based on real-time feedback.
• Exposing standard polymethyl methacrylate (PMMA) resist under optimized conditions.

Main Results:

• Achieved in situ feedback on electron beam distortion and enlargement using nitrocellulose resist.
• Successfully optimized the electron beam for uniform pattern shape and size distribution across a 1 mm x 1 mm writing field.
• Demonstrated approximately 80-nm resolution with the optimized beam, a significant improvement over the 210-nm resolution obtained without optimization.

Conclusions:

• Self-developing nitrocellulose resist enables effective in situ feedback for EBL.
• Beam optimization using this method drastically improves pattern resolution and uniformity.
• This approach offers a pathway to more precise and efficient nanoscale fabrication.