Microfluidic chip fabrication by micro-powder blasting

Micro-powder blasting uses the high speed gas flow which mixed the micro-particle and gas to impact the brittle substrate by the specialized nozzle. This research combined various diameters Al₂O₃ eroding particle with a novel masking technique to fabricate the pattern channels in soda glass with a width down to 50 mum and depth down to 90 mum. The masking technology is consisted by the combination of two polymers: (1) the brittle epoxy resin SU-8 for its photosensitivity and (2) the elastic and thermal-curable poly-(dimethyl siloxane) (PDMS) for its erosion resistance. This research uses the different processing parameters (gas pressure, nozzle/substrate distance, particle size, impact angle, and erosion time) to find the optimal process by single-parameter method. The results show that the micro-channel becomes deeper as the gas pressure increases. The micro-channel decreases the depth as the nozzle/substrate distance increases. The surface roughness of micro-channel of microfluidic chip is about 5-6 mum.