Method for fabrication of microfluidic systems in glass

In this report we describe a new way of fabricating integrated microfluidic elements in glass. By employing a matrix of underpinning posts and a thin wall, surrounding etched flow channels, an efficient sealing of glass chips substrates to thin cover glass can be accomplished. The use of this arrangement enables the overlay sheath of glass to hermetically close the flow channel by fusion bonding while avoiding problems with void or crack formation that are due to dust particles, non-planarity and differences in thermal coefficient of expansion. As an example a structure with a thin cover glass, useful for studying phenomena in capillary electrophoresis utilizing large numerical aperture microscope lenses, was fabricated.