A reproducible method for μm precision alignment of PDMS microchannels with on-chip electrodes using a mask aligner

Area of Science:

• Microfluidics
• Materials Science
• Electrical Engineering

Background:

• Lab-on-a-chip devices require precise alignment of microchannels and electrodes.
• Existing methods for aligning polydimethylsiloxane (PDMS) microchannels can be complex and lack high resolution.
• Achieving sub-micrometer alignment is crucial for advanced microfluidic applications.

Purpose of the Study:

• To develop a reproducible and high-precision method for aligning PDMS microchannels with coplanar electrodes.
• To adapt a conventional mask aligner for sub-micrometer alignment in microfluidic chip fabrication.
• To enable reliable bonding and alignment of microfluidic chips for lab-on-a-chip applications.

Main Methods:

• Utilized a silicon mold and a PMMA sarcophagus to ensure precise parallelism of molded PDMS.
• Employed a conventional mask aligner equipped with a custom steel chuck and magnets for alignment.
• Developed a technique for aligning PDMS slabs with electrodes patterned on glass chips.

Main Results:

• Achieved reproducible alignment of PDMS microchannels and coplanar electrodes with a resolution below 2 micrometers.
• Demonstrated the effectiveness of the custom chuck and magnet system in the mask aligner.
• Validated a robust method for fabricating aligned microfluidic devices.

Conclusions:

• The developed method offers a cost-effective and accurate approach for microchannel-electrode alignment.
• This technique is suitable for mass production of lab-on-a-chip devices requiring high alignment precision.
• The reproducible sub-micrometer alignment facilitates the development of advanced microfluidic systems.