Metal patterning process on rigid and flexible substrates using nanoimprint lithography and resist pattern transfer...

Area of Science:

• Materials Science
• Nanotechnology
• Lithography

Background:

• Fabricating high aspect ratio metal patterns with high fidelity is crucial for microelectronics.
• Existing methods often suffer from defects like 'rabbit ears', limiting pattern quality.
• Developing defect-free patterning techniques for both rigid and flexible substrates remains a challenge.

Purpose of the Study:

• To demonstrate a novel fabrication process for high aspect ratio metal patterns without defects.
• To achieve precise metal patterning on both rigid silicon and flexible polyethylene terephthalate (PET) substrates.
• To enable high-fidelity lift-off processes for micro- and nano-scale applications.

Main Methods:

• Utilizing UV nanoimprint lithography (UV-NIL) to create initial resist patterns.
• Employing a resist pattern transfer technique using a water-soluble polyvinyl alcohol (PVA) layer to create an undercut profile.
• Integrating a lift-off process involving UV curable adhesive, O2 reactive ion etching (RIE), e-beam evaporation, and solvent-based resist removal.

Main Results:

• Successfully fabricated high aspect ratio metal patterns with 250 nm linewidth and 80 nm thickness.
• Demonstrated the absence of rabbit ear shaped defects on both Si and flexible PET substrates.
• Validated the effectiveness of the undercut profile created by the PVA transfer layer for high-fidelity lift-off.

Conclusions:

• The developed UV-NIL based process is effective for defect-free fabrication of high aspect ratio metal patterns.
• The method is suitable for both rigid silicon and flexible PET substrates, broadening its applicability.
• This technique offers a viable solution for producing high-quality metal patterns in advanced electronic devices.