Breaking the 100 µm Barrier: Sub-10 µm 3D Microfluidic Channels via Low-Cost Maskless Photolithography

Area of Science:

• Microfluidics
• Photolithography
• Rapid Prototyping

Background:

• Microfluidic device fabrication is crucial for lab-on-a-chip technologies.
• Vat photopolymerization is advantageous but limited by over-curing and channel blockage.
• Existing methods struggle with fabricating high-aspect-ratio and small-dimension microchannels.

Purpose of the Study:

• To develop a cost-effective and precise method for rapid microfluidic device prototyping.
• To overcome the limitations of conventional photopolymerization techniques in microchannel fabrication.
• To enable the creation of microfluidic devices with sub-10 µm channel dimensions.

Main Methods:

• A modular, maskless photolithography system utilizing a digital micromirror device (DMD) was employed.
• Regional photocuring of resin was performed between prefabricated rigid substrates and covers.
• Layer stacking enabled the transition from 2D to complex 3D microfluidic architectures.

Main Results:

• Microchannels with widths as small as a single DMD pixel and heights below 10 µm were fabricated.
• The method eliminated the need for a separate sealing layer, preventing microchannel blockages.
• Achieved channel dimensions significantly surpassed the limitations of conventional 3D photopolymerization techniques.

Conclusions:

• The presented DMD-based photolithography offers a low-cost, high-precision, and rapid alternative for microfluidic device fabrication.
• This method facilitates the creation of advanced microfluidic systems with customizable properties.
• It expands the capacity for innovative microfluidic device design and application development.