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 /spl mu/m, 27.3 /spl mu/m, and 10.0 /spl mu/m in its horizontal diagonal has been simultaneously fabricated with flow channels and tested. Each mesh filters out microparticles larger than 35 /spl mu/m, 18 /spl mu/m, and 6 /spl mu/m, accordingly. In addition to microfiltering, the utility of the vertical screen filter structure as a passive micromixer has been demonstrated.