We present a three-dimensional (3D) micro-traps array for size selective sorting and patterning of microbeads via evaporation-driven capillary flow. The interconnected micro-traps array was manufactured by silicon micromachining. Microliters of aqueous solution containing particle mixtures 10 of different sizes - 0.2 to 20 μm diameter beads were dispensed onto the micro-traps substrate. The smaller particles spontaneously wicked towards the periphery of the chip, while the larger beads were orderly docked within the micro-traps array.