Microfluidic plastic capillaries on silicon substrates: a new inexpensive technology for bioanalysis chips

This paper reports the fabrication and testing of large-volume plastic capillaries and other fluidic components using a batch lithographic process. These components are fabricated on planar substrates using a simple three mask, low-temperature, IC compatible process that allows the integration of microfluidic and circuit elements. The microfluidic elements are conformal to the substrate thus overcoming the planarization required by bonded structures. In addition they have relatively large volumes in contrast to polysilicon based devices and are completely sealed in a batch manner overcoming the limitations of micromoulding. The capillaries are also optically transparent and can range from 0.5 μm to 100 μm in height. The fluidic components have been fabricated on top of regular silicon, glass, and polycarbonate wafers. Mechanical and biocompatibility tests indicate that the plastic components are suitable for DNA analysis instrumentation