A continuous tilting of micromolds for fabricating polymeric microstructures in microinjection

Area of Science:

• Materials Science
• Microfluidics
• Nanotechnology

Background:

• Microstructure-based microfluidic devices are crucial for microanalysis and lab-on-chip applications.
• Undercutting (T-profile) in photoresist during UV lithography leads to imperfect mold duplication and instability.
• Existing methods struggle with stable mold fabrication for microfluidic devices.

Purpose of the Study:

• To present a practical design and integration of multidirectional tilted UV lithography and microinjection molding.
• To overcome the photoresist undercut problem in microstructure fabrication.
• To enable the stable and durable production of microstructure-based microfluidic devices.

Main Methods:

• Utilizing multidirectional tilted UV lithography to control microstructure slope angles.
• Tilting the chuck during UV exposure to achieve slope angles up to 30 degrees.
• Integrating this technique with microinjection molding for device fabrication.

Main Results:

• Successfully prevented photoresist undercut problems through controlled slope angles.
• Facilitated easy release of microfluidic devices from the molds.
• Demonstrated high durability of the fabricated microfluidic devices.
• Achieved stable molds essential for mass production.

Conclusions:

• Multidirectional tilted UV lithography offers a simple and effective route for fabricating durable microfluidic devices.
• This technique addresses critical challenges in mold stability and device release.
• The method is suitable for microanalysis and lab-on-chip applications, enhancing production efficiency and device reliability.