New joining and automation approaches for multilayer-based manufacturing of complex, customized microsystems

Micro systems are an indispensable tool in many research areas. Their applications range from point-of-care diagnostics to drug development and personalized medicine. Hence multilayer technology is already established in modern printed circuit board manufacturing it could also enable the rapid and effective production of complex microfluidic micro systems, hence it is already cost effective for small batch sizes of 50 pieces and less. By micromachining polymer foils and subsequent thermal bonding, channels and cavities can be realized down to a minimum structure size of 50 μm. For smaller structures, free-standing structures (pillars) or structures with varying depths (e.g. micro lenses), the technology reaches its limits. Such structures can be realized by hot embossing. Nevertheless, some challenges still remain when multilayer manufacturing and hot embossing technology are combined: First the filigree, hot embossed structures must be retained during the subsequent joining processes. Second the hot embossed components are usually very thin and significantly smaller than the overall system. Successful integration requires exact positioning and handling without twisting. Here we present the realization of multilayer based micro-fluidic systems for the integration of hot embossed components. In this process, joining partners are functionalized using plasma treatment and then bonded at lower pressures and temperatures. For automated assembly, a robot-setup was adapted and customized tools were developed. A special suction gripper even enables the handling of porous membranes without warping. With the extended technology chain, smaller and freestanding structures with varying depths can be realized.