The Finnish company Beneq and the Laser Zentrum Hannover e.V. (LZH) have jointly developed a Spatial ALD system with which complex-shaped 3D objects such as optics can be coated at previously unattainable speeds on a production scale. The C2R ALD system achieves speeds of up to 200 rpm with application rates of up to 1 µm/hour. It enables precise control of the coating thickness, e.g. for highly curved, small aspherical lenses. The ALD technology (atomic layer deposition, ALD) is a self-limiting and isotropic process that can achieve a layer thickness of around 1 angstrom per cycle and can therefore produce extremely dimensionally accurate layers or nano-multilayers.
At the heart of the Spatial ALD system is a rotary table that eliminates the need for the sequential sub-processes used in batch ALD systems. Instead, pressure and nitrogen curtains geometrically separate four zones within the system. One rotation of the turntable corresponds to one ALD cycle, whereby the samples are exposed to the required reactants at different points during the rotation. The LZH is currently working on the coating of optical lattice structures and polymer optical lenses for use in virtual and augmented reality glasses using the Spatial ALD process.
