Hot embossing of microfluidic platform

Microfabrications of polymer are becoming increasingly important and considered as a low-cost alternative to the silicon or glass-based MEMS technologies. However, most of hot embossing studies were done on a thin film that may not fulfill the structure requirement of the product. In this study, micromolding via hot embossing was applied to microfeatured fluidic platform. The microfeature in the Ni–Co-based stamp includes microchannel array of approximately 27 μm in depth and 110 μm in width. A PMMA film of 1 mm thickness was utilized as molding substrate. Effect of molding conditions on the replication accuracy of microfeatures was investigated. The imprint width, imprint depth and sidewall draft angle of microchannels were analyzed and correlated. It was found that all the accuracies of the imprint depth, width and draft angle increase with the applied force until the associated dimensions reach saturated values. Embossing temperature shows similar influence on the accuracies of imprint depth and width as the applied force. Basically, 20 kN applied force and 180 °C embossing temperature can achieve acceptable results considering reasonable cycle time. However, if the applied force is increased to 25 kN accompanied with 200 °C embossing temperature and 5 min embossing time, one can obtain a nearly perfect replication.