Exploiting the oxygen inhibitory effect on UV curing in microfabrication: a modified lithography technique

Area of Science:

• Materials Science
• Microfluidics
• Photopolymerization

Background:

• Standard lithography for microfluidic channels requires multiple deposition and UV curing steps.
• Oxygen diffusion can inhibit photopolymerization, complicating microfabrication processes.

Purpose of the Study:

• To investigate and utilize the interplay between oxygen diffusion and UV curing in liquid photopolymers.
• To develop a modified lithography technique for efficient microfluidic channel fabrication.

Main Methods:

• A novel two-step UV exposure technique was employed using liquid polyurethane methacrylate (PUMA).
• The first step involved maskless UV exposure to control oxygen inhibition at the surface.
• The second step used a photomask for pattern transfer of microfluidic channels.

Main Results:

• The developed technique successfully fabricated microfluidic channels in a single coating step.
• Fabricated structure heights were correlated with oxygen concentration and UV dose.
• The process demonstrated reduced fabrication steps and improved microstructure integrity.

Conclusions:

• The modified lithography technique offers a promising approach for rapid prototyping of microfluidic devices.
• This method significantly shortens processing time and enhances the integrity of microstructures.
• The findings highlight the potential for controlled oxygen inhibition in advanced microfabrication.