Small, smaller, smallest also means clean, cleaner, cleanest. Because almost every high-tech and manufacturing company has to be more and more precise and accurate, it is logical that the cleanliness of all components must meet ever higher requirements. And those components can only be kept clean in a vacuum.
When a product is clean enough depends on the application. 'Clean for one person is not clean for another,' says Jeroen van Westing of vacuum specialist Vacutech in Den Hoorn. 'Customers sometimes come with wishes they don't need at all in practice. We advise them on this, because of course there is a price tag on how high the bar is set.'
Manufacturability and possible cleanliness start with the design, Van Westing argues. 'When we get a drawing from a customer, we add our knowledge about vacuum and clean to it. For example, it sometimes happens that a designer does not take into account the welding process. We then like to sit down with such a party - preferably as early in the process as possible - and together ensure a design that is easy to make and easy to clean.'
Advantage provides opportunities
The demand for clean and extremely clean products is increasing. Cleanrooms are popping up like mushrooms at a lot of suppliers, especially those working in the high-tech industry. The big drivers behind this trend are ASML and Thermo Fisher. 'The push from those companies and their entire ecosystem makes the Netherlands a global leader in contamination control,' says Freek Molkenboer, senior systems engineer at TNO and vice president of the Dutch vacuum association Nevac. He draws a comparison with Nevac's American counterpart. 'At the AVS a few years ago, no one had heard of ultraclean vacuum while it was already very big in the Netherlands at that time.'
Ask a Dutch high-tech supplier for grade 1 or grade 2 and he will know what is meant. 'It is probably not surprising that the term is not immediately recognized abroad, because it is ASML language, but they often do not even know there what is important at all. The Netherlands really has a head start and we can take advantage of that," Molkenboer says.
There are opportunities in the analytical market, some of which are already being filled through Thermo Fisher. In the production of OLED screens or sensors for the automotive industry, for example, cleanliness requirements are also increasing. This may not yet be at the same level as at ASML, but you can wait until these markets also have to work ultra-clean. Dutch specialists will have everything ready by then.
ASML's requirements for cleanliness are immense. 'There is no company in the world that sets the bar so high,' says Hans Cools, operations manager at IPS Innovar, which specializes in high-precision industrial cleaning. 'At Thermo Fisher and Carl Zeiss they also ask a lot in the area of clean work, but ASML sets the standard. That company has written the language for extremely clean.'
And Cools means that literally. The cleanliness levels grade 1, 2, 3 and 4 come directly from the specialists in Veldhoven. 'Recently ASML revised the grades, making them one step more stringent,' Cools says. 'I expect that trend to continue. It's not something for next year right away, but systematically it will have to be cleaner and cleaner and therefore increasingly difficult to meet the requirements.'
Actually impossible
To explain the difficulty of ASML grades, Cools gives an introductory lesson in high-tech cleaning. 'There are two major groups of contaminants: particles and molecular contamination. For particles, you have to think of dust and fibers. For grade 4, these may be 40 to 50 micrometers in size. In principle, you could achieve that with a good dishwasher. However, as soon as you take the parts out, they are already no longer grade 4 because of all the dust swirling in the kitchen, so you have to do that in a clean room. Grade 2 involves particles no larger than 20 to 30 microns. That doesn't seem like such a big step, but it's a world of difference. We have a special car wash for that. Then it's not spectacularly difficult anymore.'
Then the ultimate: grade 1. 'All particles larger than 0.5 microns must then be removed. That is actually impossible,' laughs Cools. 'That's why the requirement is that a maximum of twenty thousand per square meter may remain. That sounds a lot, but is really very little. For that you need very specialized equipment, with extensive cleaning programs.'
By molecular contamination, you have to think of coolants and lubricants, oils and emulsions that were used during the production process and left on the part. 'Largely, you can solve that with the same cleaning steps as for the particles, which mainly involve degreasing,' Cools explains. 'Then the products often go into an oven to burn everything out and a residual gas analysis follows for verification. Molecular cleaning may sound more complicated than removing all the particles, but in practice it's a little easier.'
Finally, there is such a thing as hydrogen induced outgassing. Cools: 'These are elements that break out the moment they come into contact with hydrogen. That is pernicious for the operation of the ASML machines so you have to prevent that. Unfortunately, you can't measure that inline like you can with the RGA. It has to be done at the process level. The effort for that is extremely high.'
Basic knowledge is too often lacking
ASML's grades are of course useful for all companies in the Veldhoven machine builder's ecosystem. But they are also somewhat extreme; by no means all applications need that level. 'It would be nice if there were general guidelines,' thinks Van Westing of Vacutech. 'Even grade 4 is by no means always an issue. Guidelines have been drawn up from TNO and Nevac, but they are not international. A general standard in the industry would be very nice.'
Van Westing notes that many engineers lack basic knowledge about vacuum and clean. 'We almost always have to retrain new employees. Although we are in a fairly specialized field, the market is growing so fast that all suppliers in the chain have to keep up. And that's not a given.'
Molkenboer adds: 'It would be very good if vacuum and clean became a standard subject at technical universities, at colleges of higher education and at intermediate vocational schools. Because in general there is too little attention to it now, while its importance is only increasing. Without vacuum and clean, we would be years behind in a lot of developments.'
Cools also notices the pressure on the labor market. 'Everyone is building clean rooms but they also need to be filled with people. It's challenging anyway to find enough technical staff, but people with cleanroom experience are even more scarce,' Cools said. 'With the growth that ASML, for example, wants to experience in the next few years, we need a lot of people everywhere. Part of the puzzle is to automate more; not because we have to out of cleanliness, but simply to be able to solve it with the available staff. You can already do a lot with machines, but it's about using them in the right way. That is human work, the craftsmanship of vacuum and clean.'
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