Using femtosecond laser to fabricate highly precise interior three-dimensional microstructures in polymeric flow chip

Area of Science:

• Materials Science
• Microfabrication
• Laser Technology

Background:

• Fabricating precise 3D microstructures in closed systems is challenging.
• Traditional methods like mechanical drilling can damage delicate structures.
• Laser ablation offers a non-contact, high-precision alternative.

Purpose of the Study:

• To report the use of femtosecond laser marking for fabricating 3D interior microstructures.
• To demonstrate the precision and advantages of this technique for plastic substrates.
• To address limitations of conventional microfabrication methods.

Main Methods:

• Utilized a femtosecond Ti:sapphire laser (800 nm, ~120 fs pulse duration, 1 kHz repetition rate) for ablation.
• Fabricated strip-like slots (800 μm×400 μm×65 μm) on acrylic slides.
• Employed defocused beams for surface finishing and sonication for polishing.

Main Results:

• Achieved highly precise microstructures with arithmetic roughness values of 1.5 nm and 4.5 nm.
• Demonstrated the capability to engrave interior microstructures directly within a closed chip.
• Confirmed that femtosecond laser marking surpasses nanosecond laser marking and mechanical drilling in precision.

Conclusions:

• Femtosecond laser marking is a superior method for fabricating high-precision 3D microstructures in closed plastic channels.
• This technique eliminates the risk of damage associated with chip sealing procedures.
• The method enables advanced microfluidic device fabrication with enhanced accuracy and integrity.