Paul van Gerven
23 December 2021

Now that display manufacturers’ appetite for new deposition technology has faded for the moment, startup SALDtech is forced to explore other markets.

It’s not like the original business case is out the window, but a plan B was definitely needed, says CEO Huib Heezen of SALDtech. Initially aiming to introduce spatial ALD equipment – a real Dutch specialty – in display manufacturing, the TNO spinoff founded in 2018 has recently broadened its scope to include energy technology applications, such as electrolyzers, fuel cells and batteries. What happened?

What would spatial ALD bring to display manufacturing?

Heezen: “We were targeting two applications. One is to deposit encapsulation layers, which protect delicate OLED materials against moisture and oxygen. ALD enables much thinner layers compared to plasma-enhanced chemical vapor deposition, which is currently being used to deposit barrier layers. Thin layers are advantageous for flexible displays and, in certain cases, for rigid displays too.”

“Additionally, our version of the spatial ALD process eliminates the need for a mask to prevent deposition of material in between displays. Phone displays, for example, are manufactured on large substrates and cut to size afterward. Since material deposited in between displays can cause contacting problems, a mask is used during deposition steps to separate the displays. This mask introduces process complexity because it needs to be positioned, and since material is deposited on it, it needs to be cleaned regularly to prevent contamination issues. This causes downtime and additional cost, so manufacturers are eager to dispose of it.”

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SALDtech render
Render of SALDtech’s tool about to process a (patterned) glass substrate. Credit: SALDtech

“The other application is the deposition of indium gallium zinc oxide, a semiconductor material used to make the TFT backplane that controls the pixels. With ALD, it’s possible to make atomically precise nanolaminates of IGZO’s constituents, which increases electron mobility, which in turn allows for smaller pixels, and thus for higher resolution, as well as for higher refresh rates. We demonstrated IGZO with an electron mobility that’s several factors higher than what was being used currently.”

So why haven’t display manufacturers ordered SALDtech’s equipment yet?

“In a word: Covid. Several major display manufacturers had made clear that they were interested in buying our equipment once we could meet their specifications. We were quite far along when the pandemic started. First, this prompted the industry to adopt a wait-and-see position, then it hastily started expanding manufacturing capacity in response to the pandemic-driven increase in display demand. Under such circumstances, they don’t adopt new technology.”

“Things have started to settle down a little, but it’s still impractical – if not impossible – to travel to Asia. If you can’t meet your potential customers, it’s impossible to keep the process toward our first sale going. That’s why we started looking at other applications. There are still opportunities in the display market for us, but they’re on hold for the time being.”

Why is energy technology a good fit with ALD?

“Energy technology often involves porous materials to increase the surface area at which electrochemical reactions take place. ALD features great step coverage, meaning it’s very suitable for coating 3D materials. Such coatings provide a reactive surface or increase stability, for example. Of course, our technology was originally developed for flat surfaces, so we need to do a bit of optimization to handle 3D substrates.”

SALDtech’s course change means you’ll compete with SALD, which was carved out of TNO spinoff Solaytec after spatial ALD bombed in the solar market. You know that company well because you served as its CEO for years. Do we really need two Eindhoven-based companies working on the same technology and aiming at the same markets?

“I agree it would be ideal if we could work together. For a variety of reasons, that hasn’t happened yet. In the meantime, I hope that we can keep our overlap to a minimum. There are plenty of companies in the world selling ALD equipment; there’s no need for two ‘neighbors’ to try and outcompete each other.”