René Raaijmakers
20 January 2017

At TNO, research and developments in optics, sensors and EUV are spinning off knowledge into multiple markets. The research institute is also building an EUV facility where players in the semiconductor industry can test their recipes and materials for future nanometre nodes.

In 1998, ASML called upon TNO to help develop expertise in exposing chips using extreme ultraviolet radiation. The move made sense: thanks to the technology’s vacuum requirement, the conditions for EUV chip lithography are a good match for aerospace instrumentation – one of the research institute’s core competencies. For the past fifteen years, the group in Delft has also been working with Carl Zeiss to keep the mirrors for EUV optics clean. And since 2005 the South Holland city has been home to an EUV test system. In recent years this demanding discipline has generated such a wealth of knowledge that TNO is now tutoring organizations like ESA on topics such as contamination control.

In this kind of research and development process, TNO usually takes a pioneering role. ‘We’re more involved in revolutions than evolutions,’ says Rogier Verberk, TNO’s director of semiconductor equipment. For the first experimental EUV alpha tool, his team created roughly fifteen modules, ranging from sensors through electrostatic clamps for EUV masks to systems for contamination control and reticle handling.

As requested by ASML, this knowledge has since been transferred to the company and its suppliers. TNO’s role in further product development will be purely advisory. The peak days are over; the hours spent on EUV R&D in Delft have dropped to a quarter of what they once were. The research institute is now applying what it’s learned in a variety of other fields.

EUV TNO particle scanner
In future production equipment, even the tiniest debris can create chips that don’t work and wreak major financial damage on chip manufacturers. TNO’s newest Rapid Nano particle scanner can detect particles of just 22 nm on surfaces, such as reticle banks.


Meanwhile, TNO is assuming a key role in the global ecosystem for chip fabrication. The institute in Delft is currently building a special measurement facility, the EUV Beam Line 2 (EBL2), a vastly improved version of the 2005 system. The entire chip industry can use it to study its contamination issues in EUV environments. In addition to suppliers of EUV infrastructure and materials, all chip manufacturers with an EUV roadmap have already demonstrated interest. Semiconductor companies want to use the EBL2 to test their recipes for upcoming nanometre nodes. The materials and infrastructure suppliers include developers of EUV masks, pellicles and sensors that are used in the vacuum. In Delft, they want to test ways to keep their products clean and durable.


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A special feature of the EBL2 is that samples can be inspected using spectroscopic x-ray technology, cleaned with a plasma and irradiated with EUV, without having to be transferred from one machine to another. That makes the system’s measurements much more reliable – otherwise, it would be impossible to determine when contamination had occurred.

For a long time, the companies that play a role in EUV infrastructure seemed to have a wait-and-see attitude. That hesitation was a potential showstopper. Without infrastructure, there can be no EUV lithography. The EBL2 lowers the threshold for jumping in: not every research group can afford an EUV source or scanner. That fact gave TNO an opportunity to commercialize its expertise in vacuum technology and contamination control. Verberk expects the institute to be able to fully exploit the commercial potential of the EUV Beam Line service.

The source in the EBL2 was made by Ushio. It’s future-proof, meaning it operates beyond the 250 watts that ASML has set as its goal. The EBL2 produces lower power, but the radiation intensity on the samples is comparable to that of an ASML scanner. ‘We’re the only ones who have this flexibility,’ Verberk says. ‘You can also go to a synchrotron and ask for an EUV exposure, but in that environment you can’t experiment and the light isn’t the same as that in the ASML scanner. At our facility, customers run their own show, and there are five operators and experts standing by to help them.’

Working with Ushio over the past several months, TNO has built the EUV Beam Line 2. The test system will be switched on this December, and in March the first research programmes using the EBL2 should be up and running.


Leading companies in inspection and metrology have also found their way to Delft. Both KLA-Tencor and Applied Materials want to make use of TNO’s expertise in contamination control. In this discipline, the institute is also working on new concepts itself, Verberk notes. ‘Inspection and metrology are lagging behind lithography, while the entire chip industry is clamouring for solutions.’

TNO has traditionally been strong in optical inspection and metrology. It’s since added another flavour to its offerings: technology based on atomic force microscopes. An application that can inspect a 300-mm wafer is now being further developed by spin-off Nearfield Instruments. ‘Nearfield is still at an early stage, but it’s moving fast,’ Verberk says. ‘The investments necessary to move from concept to machine are large. That’s why we turned it into a separate company. The end users tell us that scanning probes are relevant.’

In any case, it underscores the industry’s desperate search for new inspection and metrology methods. Optical technologies are having increasing difficulty seeing and calculating today’s tiny features. ‘There, too, we will continue to work with the industry to use smart solutions such as adaptive optics and computational optics to increase quality and capabilities,’ says Verberk.


Companies encounter substantial obstacles during the pioneering phase of product development, Verberk knows from experience. That’s precisely where TNO’s innovative strength lies. ‘For a completely new product, smaller companies in particular have to learn new disciplines. TNO can help them clear those hurdles. Once they’ve been overcome, these companies can usually handle the rest themselves.’

Those hurdles are not only technological, but also often financial. For that reason, TNO and TU Delft decided this year to tackle the problem by setting up the Dutch Optics Centre. There, the institute is working with companies and other research institutes. ‘We’re now in talks to set up a fund for true market innovations, things that have real economic value for the Netherlands but whose financial risk is too high for small companies. We’re proposing that the government hedge that risk. It need not be a gift; it could be a deferred-payment loan, for example. We’re talking about complex developments that are hard for banks to understand. So it helps to have an environment where the Ministry of Economic Affairs is more willing than commercial banks to delve into the subject.’

The idea for the Dutch Optics Centre arose in part from TNO’s optics manufacturing facilities. ‘We can create very difficult things: lenses, mirrors, gratings in the most unusual shapes. Everything that isn’t commercially available,’ Verberk says. ‘But that capacity isn’t being fully exploited. That’s why we asked several organizations to brainstorm with us on whether and how to maintain this facility, because it requires substantial investments.’

Here, too, ASML’s influence over the past decades has been significant. ‘It’s given the Dutch optomechatronics industry an enormous boost,’ says Verberk. Thanks to its position as an expert, TNO has evolved into a global go-to for questions on optics and optomechanics. ‘We’re also in contact with the Intels and Samsungs of this field. We play the role of the front door. Through us, large customers gain access to the entire network of Dutch suppliers.’ TNO’s strategy is to grow the Netherlands’ economic pie. ‘Then we’ll see how we slice it up,’ Verberk says.

The Dutch Optics Centre opened its doors last October. Its member organizations are currently creating business cases and setting up projects, Verberk says. ‘We’ve identified several topics where we can develop new product-market combinations within a few months.’ The inspiration is provided largely by TNO’s semiconductor and aerospace network, but Verberk also sees opportunities for medical applications. For example, he expects that specific sensor developments in the semiconductor equipment industry and aerospace can also lead to products for the medical industry.