The spatial Atomic Layer Deposition (sALD) technology developed by Holst Centre (TNO) is a ground-breaking innovation for the large-scale production of flexible solar collectors, OLED lamps, sensors and displays. The possibility to produce uniform, ultra-thin layers of chemical substances on large surfaces is of great importance to the global high-tech industry. The long-term cooperation between knowledge institutes and businesses in the Eindhoven region made it possible to transfer this innovative technology from the lab to the manufacturer.
ABOVE: Schematic view of the roll-to-roll spatial ALD concept. A polymer foil is transported around a drum that houses injector slits (blue and red) for the reactive precursors, separated by inert gas (green). By moving both the web and the drum, a thin ALD-coating is applied on the polymer foil at high rate.
Global manufacturers of solar panels and batteries as well as their customers such as the automotive industry aim for higher returns of the energy conversion, more efficient power consumption, higher energy storage capacity combined with shorter charging times and a longer product lifespan. In all these growth markets short production times against the lowest possible costs are essential for success. Scientific testing has shown that sALD, a Holst Centre (TNO) invention, can play a decisive role in achieving this success.
Cooperation provides opportunities for a sALD revolution
Based on the sALD technology, VDL Enabling Technologies Group (VDL ETG) currently designs and builds machines that enable companies such as SALD and SALDtech to market their products. In this respect, SALD has taken up the role of equipment OEM of R2R and S2S sALD machines while SALDtech delivers OEM solutions particularly aiming at OLED applications. By doing so, four Dutch companies have created an enormous potential by completely embracing an advanced core technology, developing it and positioning it in emerging markets. The cooperation between scientific organisations, investors, regional governments and enterprises from the Brainport region enables large-scale production, increasing the opportunities for the Netherlands in today’s growing industrial sectors worldwide.
ALD versus sALD technology
Atomic Layer Deposition (ALD) is mainly known from the production of integrated circuits in the semiconductor industry. Using this technology, a substrate is consecutively exposed to precursors in a vacuum chamber. Ultra-thin layers are deposited with high compositional control, greatly improving the characteristics of the end product. However, this process is slow as one layer has to be completed before the deposition of the next layer can start. In order to achieve a high-volume production, multiple machines are used simultaneously, each producing its own batch of products. This leads to long production cycles and requires large footprints in expensive cleanrooms.
In 2008, TNO scientists created an innovative solution to mitigate the deficiencies of the conventional ALD process. They developed a technology in which an advanced deposition head combines multiple sequences of precursors to consecutively reach a fast-moving substrate. This improved version of ALD was called spatial ALD and with it, TNO managed to increase the production speed up to 100 times while retaining the coating quality. Tests showed that solar panel efficiency could be greatly improved. VDL ETG Projects and Holst Centre (TNO) collaborated in scaling up the new ALD technology to larger foil and panel sizes in R2R (roll-to-roll) and S2S (sheet-to-sheet) tools, respectively. These tools are used to research the protection of sensitive, flexible solar panels against grim environmental conditions, increasing their lifespan. VDL ETG continues to cooperate with its partners to adapt the sALD tools and make them suitable for other applications like flexible batteries, flexible OLED displays, etc.
More info: Holst Centre