Cab-nanoelectronics

Nanoelectronics Silicon based microfluidic platforms

 

Silicon based microfluidic platforms that enable the miniaturization, integration and automation of biochemical assays for lab-on-a-chip applications are being fabricated using a combined DRIE/XeF2 micromachining technique that enables having microchannels buried underneath the silicon substrate at different levels.

Complex and long fluidic paths can thus be processed within smaller sample areas and with very small footprint. The resulting chip surface is passivated and sufficiently flat to allow further processing of functional devices (sensors and actuators) on top of it for enhancing fluid transport, metering, mixing, switching, incubation, separation, droplet formation and splitting, nL and pL dispensing, and detection.

The several stages for the production of such silicon microfluidic chips are (a) to pattern silicon oxide on top of the substrate at the channels locations, (b) etch narrow and deep trenches by DRIE (1-2 µm by 20-30 µm), (c) isotropically etch the bottom of the trenches using XeF2 gas and closed channels by conformal PECVD deposition of oxide and nitride layers.