Film Coating - Large Area Encapsulation Process for Electronics Packaging

For improved reliability of microelectronics an encapsulation of sensitive structures is crucial, this is true especially for polymer electronics, where oxygen diffusion and water vapor ingress do dramatically influence the electrical performance. For the protection of semiconducting polymers within organic LEDs a glass layer is the method of choice, providing optimized sealing except for the edge areas. Disadvantage of glass as a sealing material is its rigidity and its sensitivity against mechanical stress. For the realization of low cost applications as smart labels / RF ID tags besides barrier properties also mechanical protection is needed to ensure device functionality. This is especially true when these devices need to operate within harsh environment. Various approaches are possible to apply such barrier layers, typically CVD/PVD or spin coating are used, to yield thin, homogeneous layers of encapsulants of 1 to 5 μm thickness. For the high speed encapsulation of large areas also lamination is discussed, where multilayer films are applied using temperature and pressure, layer thickness is in the range of 5 to 30 μm. As a further technology, suited for the deposition of low viscosity liquid barrier materials, film coating processes are proposed. Focus of the technology development described is the application of homogeneous coating on large areas. Expected advantage is the contactless application at high speed on large area substrates, especially useful on substrates showing a 3D topography, as present with devices integrating heterogeneous structures as organic semiconductors (OSC), printed passives or coils.