Fabrication of glass-based microfluidic devices with photoresist as mask

Abstract

This paper presents a low cost method for etching of glass based microfluidic devices. Microchannels with the depth up to 150 μm were achieved by implementing a photoresist and wet etching process. In particular, a photoresist based mask method is introduced for glass etching which can strongly resist against etchant attacks up to 2 hours, showing high adhesion properties on glass substrate for fabrication of microfluidic microchannels. The width of the channels is determined by the width of the lines in photo-mask design and the rate of glass isotropic etching. The channel width range about 30μm to 350μm is fabricated. Commercially available inexpensive microscopic glass slides have been used as substrate. Achieving smooth and clear surface after wet etching process is an important factor for easily flowing fluid through channels and monitoring purposes. It is achieved by implementing special etchant with adding HCL in diluted BOE solution to get smooth and clear surface. The etch rate of the glass strongly depends on the concentration of the etchant. A mixture of different solutions with special ratios has been applied. Finally, typical UV curable glue is utilized for glass-glass bonding.