Fabrication of multilayered microfluidic 3D polymer packages

The realization of microfluidic packages by stacking and bonding several layers of microstructured polymer films opens up the potential of creating complex three-dimensional microfluidic structures based on relatively simple two-dimensional manufacturing processes. Whereas a multitude of microstructuring techniques have been developed, packaging and bonding technologies for multilayer microfluidic devices are still underrepresented. Bulk bonding processes like thermal diffusion bonding fit well into a lab environment, but feature extensive bonding times. With increasing fluidic complexity, bonding technologies that enable selective bonding and sealing at pre-selected areas (e.g. around channel walls or process chambers) are required. Selective bonding technologies enable a localized heat generation exactly at the desired bond position and thus significantly reduce the risk of structure deformation and channel clogging. In this paper, experimental results for a variety of bulk and selective bonding methods are reported and compared. Surface modification of polymers and lasers welding of polymer sheets are identified as suitable technologies for integration with high-throughput production environments.