Fabrication of on-chip microcapillary using photosensitive glass

The on-chip microcapillary applying for electrophoresis analysis device has been fabricated on photosensitive glass. This process can make a high aspect-ratio channel structure. The channel-depth can be controlled by varying wet-etching time without widening the channel width because the substrate material has vertical high etch rate selectivity. This high aspect-ratio structure obtains a long optical path and appropriate sample volume resulting in high-sensitivity for various analyses. The fabrication process is simpler than a usual glass micromachining process because of photo-resistless lithography process. In order to smooth the channel surface and to attach a cover glass onto the substrate, a polysilazane coating process is proposed and revealed to be effective.