Fabrication of self-sealed circular nano/microfluidic channels in glass substrates

We realized self-sealing fluidics channels with circular cross-sections having diameters ranging between 30 and 2000 nm on a 200 mm glass wafer through CMOS compatible processes. Lateral voids were narrowed and sealed with non-conformal plasma enhanced chemical vapour deposition (PECVD) of phospho silicate glass (PSG) along silicon oxide trenches on silicon wafers. Leveraging on the reflow properties of PSG, circular profiled-channels were formed after undergoing high temperature annealing. These devices were subsequently transferred onto a borosilicate glass substrate through anodic bonding, and a fully transparent microfluidic device was achieved with the complete removal of the handle silicon substrate. The process offers a means of integrating electrochemical and optical sensing on the same platform, for biological research.