Organic thin film devices, especially organic electroluminescent devices or organic photo voltaic devices comprise multiple structured layers such as electrodes or shunt lines (sometimes also denoted as mesh lines) deposited on top of the electrodes to distribute the current without significant losses over a large electrode area. Existing manufacturing processes rely on masked deposition and/or lithography processes in order to provide structured layers. The use of masks requires large preparation (each structure requires an individual mask) and process control effort (accurate mask-substrate alignments mandatory) and is therefore a quite expensive process. Furthermore, accurate structures also require an expensive tool for high resolution lithography. Therefore, a demand for reducing the manufacturing costs exists. Self-aligned deposition of layers are known from document WO 2010/034815 A1, where electrically conductive metal structures for transistor devices are created using photoresist layers and shielding structures deposited prior to the photoresist layer. During the irradiation process for the photoresist layer, the shielding structures acts as a mask and corresponding conductive metal pattern could be created in the areas outside the shielded areas.
In contrast to transistor devices, organic electroluminescent devices (OLEDs) and/or organic photovoltaic devices are large area devices. Roll-to-roll processing is a promising manufacturing technique for organic thin film devices for reducing the manufacturing costs, where masks are widely replaced by alternative processes like laser deposition, laser ablation, photo-lithography and/or printing technologies. However, the applied structuring technologies lead to geometries of the particular layers being not as accurate as present in case of masked deposition and/or the occurrence of particles or small material areas adjacent to the desired structures (so-called satellite structures) increases. Especially the occurrence of small metal satellite areas outside the desired metal areas is a critical and non-avoidable effect increasing the risk of shorts between the layers. Metal particles or metal areas outside the desired deposition location and/or with a non-smooth shape will shorten the lifetime of organic thin film devices due to occurring shorts during the operation of these devices. Applied cleaning steps to remove the satellite areas require a very high effort due to the non-regular pattern and non-predictable position of such non-desired metal areas, which could be very small, eventually non visual to human eyes. Aggressive cleaning steps may be able to remove metal satellites, but would also negatively affect the intended metal deposition areas. Passivation of satellites with additional layer coated on top is often not applicable due to the wide and random spread of satellites, their hardly detectable position and their small, sometimes non-visual size. Additionally deposition processes like printing technologies provide desired layers but with irregular shapes or frayed edges requiring an electrical passivation as well to avoid shorts. A reliable passivation of areas with non-straight borders using mask technologies for applying the passivation layers will result in passivated areas larger than theoretical necessary and/or uncovered areas. Due to the non accurate structures, mask coating of the printed structures is difficult and may lead to a waste of functional area, e.g. to generate light.
USPTO Backgrounds
USPTO Backgrounds