Direct assembly of cyclic olefin copolymer microfluidic devices helped by dry photoresist

A generic method for rapid, reproducible, and robust selective bonding of microfluidic chips made of Cyclic Olefin Copolymer (COC) has been developed and optimized. In this work we propose an adhesive bonding technique using ORDYL negative dry film photo-resist as glue to perform the packaging of COC micro-patterned structures. The ORDYL resist is qualified in terms of resolution, biocompatibility and fluidic sealing. The adhesive bonding is achieved by laminating a thin layer of ORDYL SY300 (<17 μm) on top of the microfluidic part and then bonded to the other COC part. In this research, an oxygen plasma treatment for adhesion improvement was performed on COC surfaces at various plasma times. The bonding method is described in detail and the bonding quality of the chips was evaluated by a shear strength testing procedure and a leak test by pressurizing a microfluidic channel with an aqueous solution using an external peristaltic pump. Results are reported emphasizing the efficiency of the proposed approach and the developed process features high yields (>70%).