Safety valve in PCB-MEMS technology for limiting pressure in microfluidic applications

A safety valve that prevents liquid from flowing through a fluidic circuit when its pressure is larger than a certain threshold is presented in this paper. The valve has been designed to be integrable in PCB fluidic systems, and its parameters can be modified easily to adapt the threshold pressure. Fabrication process uses PCB as the substrate, and the copper present as a sacrificial layer. Structural part is made of negative photoresist SU-8, which is deposited on top of copper and is released to form a suspended beam when copper is etched away. The experimental characterization of the valve is presented, showing its correct operation.