Nano mesh thin film microfluidic device design based on focused ion beam and MEMS machining method

The invention relates to a nano mesh thin film microfluidic device design based on a focused ion beam and an MEMS machining method. The invention discloses a method for machining a nano mesh thin film microfluidic device by using a focused ion beam. The method comprises the following steps: 1) emptying a back cavity of a substrate by KOH erosion so as to suspend a region for preparing nano meshes; 2) designing an ''initial interference'' graph, presetting the ''initial interference'' graph on the obtained suspended thin film with the aid of FIB so as to induce a rayleigh instability direction, carrying out FIB large-area scanning, and obtaining a suspended nano mesh thin film structure with a smooth surface by controlling FIB energy, dosage, scanning layout, scanning time and dwell time; 3) obtaining a nano mesh microfluidic device on the prepared nano meshes by deposition and sputtering technology and bonding with a PDMS flow channel; 4) controlling the characteristics of double electrode layers of the surfaces of a metal mesh outer dielectric layer by regulating voltages at two ends of a metal electrode, wherein target substances in a solution can be controlled and detected; and 5) further improving device control and detection capabilities and applicability by accurately controlling size parameters of the nano meshes.