Low Voltage Electrowetting-on-Dielectric Platform using Multi-Layer Insulators.

Area of Science:

• Microfluidics
• Surface Science
• Materials Science

Background:

• Electrowetting-on-dielectric (EWD) is a key technology for microfluidic manipulation.
• Achieving low actuation voltages is crucial for portable and low-power EWD devices.
• Optimizing insulator properties and fabrication processes are essential for device performance.

Purpose of the Study:

• To develop and characterize a low-voltage, multi-layer insulator EWD platform.
• To investigate the relationship between insulator properties and actuation voltage.
• To demonstrate precise droplet dispensing from on-chip reservoirs.

Main Methods:

• Fabrication of EWD devices using a multi-layer insulator (tantalum pentoxide, parylene C, CYTOP).
• Utilized a two-level-metal process for high-density electrode integration.
• Measured droplet dispensing and actuation threshold voltages for various insulator configurations.

Main Results:

• Dispensed 300pl droplets from 140nl reservoirs with voltages as low as 11.4V.
• Actuation threshold voltage of 7.2V achieved with a 1Hz switching rate.
• Observed threshold voltage scaling consistent with theoretical models.
• Demonstrated low voltage actuation for scaled devices with 30pl droplets.

Conclusions:

• The developed EWD platform enables low-voltage, high-precision micro-droplet manipulation.
• The multi-layer insulator design and two-level-metal process are effective for enhancing EWD performance.
• This technology holds promise for advanced microfluidic applications requiring minimal power consumption.