Fabrication of Passive Micromixer using a Digital Micromirror Device-based Maskless Lithography System

We developed a maskless lithography system using a digital micromirror device (DMD). This system incorporates a light-emitting diode (LED) driver to generate ultraviolet (UV) light, illumination optics using a fly-eye lens, and telecentric projection optics to generate a parallel light source reflected from the DMD. The potential problems caused by using a mask (e.g., increased expense, increased time for processing, contamination, and alignment problems) can be circumvented with the proposed maskless system. Exposure energy intensity and the micropattern-generating performance were tested with the developed system. To investigate the performance of the developed system, a passive micromixer was fabricated using the soft lithography process. The molds for the micromixer were fabricated using the proposed DMD system and a conventional UV lithography system. Mixing experiments were performed in order to compare the performance of the micromixers fabricated using both approaches. The surface texture of the micromixer fabricated by the DMD system induced more vortex flow in the channel and thus the micromixer showed approximately 10% higher mixing performance.