Fabrication of polymer microfluidic devices with 3D microfeatures that have near optical surface quality

A low cost manufacturing method for creating polymer microfluidic devices with microfeatures that have near optical surface quality is described in this paper. The manufacturing method involves laser micromachining, partial hot embossing, and molding (LHEM) to create polymethylmethacrylate (PMMA) mold masters for device replication. A metallic hot intrusion mask with the desired microfeatures is first machined by laser and then used to produce the mold master by pressing the mask onto a PMMA substrate under applied heat and pressure. The resultant 3D micro-reliefs have near optical quality surface finishes. Design parameters such as the height and width of the extruded features are investigated in this study. The experimental results demonstrate that different heights of the extruded features of a mold master can be fabricated using a single mask at a set of process parameters. Examples of curved microchannels of the PMMA mold masters and an integrated microchannel/microlens of the mold master are presented to illustrate the proposed methodology.