Integrated vertical screen microfilter system using inclined SU-8 structures

A multidimensional, vertical screen filter system is developed in which structures analogous to the mesh of a window screen are extended vertically through the cross-sectional area of a simultaneously-formed flow channel. Vertical screens with heights of up to 400 microns and aperture sizes of 10 microns have been achieved in a simple, multiexposure fabrication approach without the need for stacking or lamination. A triple filtering system with multiple inlet and outlet streams and three different mesh sizes of 57.3 μm, 27.3 μm, and 10.0 μm in its horizontal diagonal has been simultaneously fabricated with flow channels and tested. Each mesh filters out microparticles larger than 35 μm, 18 μm, and 6 μm, accordingly. In addition to microfiltering, the utility of the vertical screen filter structure as a passive micromixer has been demonstrated.