A new mold structure to replicate patterns over 1 microm in depth for substrate conformal imprint lithography

Area of Science:

• Materials Science
• Nanotechnology
• Lithography

Background:

• Conventional mold replication for substrate conformal imprint lithography (SCIL) faces challenges with deep patterns (>1 micron).
• Hard polydimethylsiloxane (h-PDMS) used in traditional methods exhibits poor mold detachment from silicon masters with intricate features.
• Weak adhesion between polyurethane acrylate (PUA) and polydimethylsiloxane (PDMS) layers hinders effective pattern transfer.

Purpose of the Study:

• To develop an improved mold replication process for SCIL.
• To enable the fabrication of UV imprinting molds capable of replicating patterns deeper than 1 micron.
• To overcome the limitations of conventional h-PDMS based replication methods.

Main Methods:

• Fabrication of a novel UV imprinting mold using polyurethane acrylate (PUA).
• Integration of polyethylene terephthalate (PET) film as a bonding layer between PUA and polydimethylsiloxane (PDMS).
• Utilizing the modified replica mold in the substrate conformal imprint lithography (SCIL) process.

Main Results:

• Successfully replicated patterns with depths exceeding 1 micron.
• Demonstrated easy mold detachment from the silicon master.
• Achieved effective pattern transfer using the modified replica mold in SCIL.

Conclusions:

• The proposed PUA/PET/PDMS mold replication strategy significantly improves deep pattern fabrication in SCIL.
• The use of PET as a bonding layer effectively addresses adhesion issues between PUA and PDMS.
• This enhanced process facilitates the production of high-fidelity molds for advanced micro/nanofabrication applications.