Gaining Micropattern Fidelity in an NOA81 Microsieve Laser Ablation Process.

Area of Science:

• Materials Science
• Biotechnology
• Microfabrication

Background:

• Microsieves fabricated using soft-lithography and laser micromachining are crucial for cell capture via passive pumping.
• Achieving high reproducibility in micropore geometry is essential for consistent cell capture yield and survival.

Purpose of the Study:

• To investigate and optimize the micropattern fidelity of Norland Optical Adhesive 81 (NOA81) microsieves.
• To determine the key fabrication parameters controlling the formation of three-dimensional (3D) micropores.

Main Methods:

• Soft-lithography and laser micromachining were employed to fabricate NOA81 microsieves.
• Systematic investigation of NOA81 film thickness, laser pulse repetition rate, number of pulses, and beam focusing distance.
• Characterization using scanning electron microscopy (SEM) and focused ion beam (FIB) for cross-sectional analysis.

Main Results:

• The number of laser pulses was identified as the dominant factor controlling pore aperture formation for NOA81 films.
• Laser pulse repetition rates between 50 and 200 Hz showed no significant influence on micropore quality.
• Optimized laser ablation conditions resulted in smooth micropore surfaces with minimal debris.

Conclusions:

• The combined soft-lithography and laser micromachining process enables the creation of high-quality, reproducible 3D micropores in NOA81.
• The established process window is sufficiently large for reliable biological applications, including cell capture.