The EUV chain: how ZEISS and TRUMPF sit inside every leading-edge chip
ASML builds the world's only EUV lithography machines. But the light source laser comes from Ditzingen's TRUMPF and the mirrors from ZEISS. A look at Germany's place in the chip supply chain.
Every advanced processor in a modern smartphone or AI data centre is patterned using extreme ultraviolet light. The machines that do this are made by one company, ASML of the Netherlands, which is the only manufacturer of EUV lithography systems in the world. Less widely understood is how much of each machine is German. Two of its most critical subsystems, the drive laser and the optics, come from Baden-Württemberg.
Why EUV is so hard
Chipmaking is a printing process. Light is shone through a pattern, or reflected off one, and focused onto a silicon wafer coated with a light-sensitive layer. The shorter the wavelength, the finer the features that can be printed. EUV light has a wavelength of 13.5 nanometres, far shorter than the deep ultraviolet used in earlier generations. But there is no convenient lamp for it, and almost every material absorbs it, including air and glass. That means the light must be generated in a vacuum and steered entirely with mirrors.
TRUMPF: making light from tin
The light source is the part of the system that sounds least plausible. According to TRUMPF, a droplet generator fires 50,000 tiny droplets of molten tin every second, and each droplet is hit by a pulse from a high-power CO2 laser. The impact turns the tin into a plasma that emits EUV radiation. The laser that does this, the TRUMPF Laser Amplifier, is built around a CO2 laser running in continuous-wave operation and amplified into precisely timed pulses.
TRUMPF, a family-owned machine-tool and laser group headquartered in Ditzingen near Stuttgart, was already a leader in industrial cutting lasers before it took on EUV. The project drew on decades of experience with CO2 lasers for sheet-metal processing, scaled up to a level of power and stability that few other firms could attempt.
ZEISS: mirrors at atomic precision
Once generated, the EUV light must be collected, shaped and projected onto the wafer. That is the job of the optics from ZEISS, whose semiconductor manufacturing technology unit, ZEISS SMT, is based in Oberkochen. ZEISS describes itself as ASML's strategic partner and the supplier of optics for its lithography systems.
The numbers for the newest generation, known as High-NA EUV, are striking. According to ZEISS, the numerical aperture rises from 0.33 to 0.55, which allows features below ten nanometres to be imaged. The projection optics contain more than 40,000 parts and weigh about twelve tonnes. Each mirror is roughly twice as large and ten times as heavy as its predecessor, is built from more than 100 layers to atomic precision, and takes around a year to manufacture. The mirrors are measured in vacuum chambers five metres across with an instrument that weighs about 150 tonnes. The company says more than 1,200 network partners are involved in the effort. These are the ZEISS EUV optics that make High-NA possible.
A tightly bound partnership
The relationship between ASML and ZEISS is closer than a typical supplier contract. In 2016 the two companies announced a strengthened partnership for the next generation of EUV, under which ASML took a minority stake in Carl Zeiss SMT and committed to support its research and development. The logic is plain: neither company can build an EUV machine without the other, so their roadmaps are effectively joint.
What this means for Europe
Discussions of chip sovereignty often focus on where fabs are built. The EUV chain is a reminder that strategic leverage can sit further upstream. A handful of firms in the Netherlands and southern Germany supply capabilities that no one else currently offers at this level, and they do so from regions better known for machine tools and precision optics than for semiconductors.
There are lessons for policymakers too. Neither TRUMPF's laser nor ZEISS's optics emerged from a semiconductor strategy. They grew out of long-standing industrial specialisms, cutting lasers and precision glass, that were patiently extended into a new field over many years. That kind of capability cannot be bought quickly, which is precisely why it is valuable.
Risks in a concentrated chain
Concentration cuts both ways. A chain in which each critical step has a single qualified supplier is efficient when demand is steady, but brittle when it is not. Capacity at ZEISS and TRUMPF has to be planned years ahead, because the skills, clean rooms and test equipment involved cannot be expanded at short notice. Export controls add a political dimension: decisions about which customers may receive EUV systems are taken by governments, and they directly shape the order books of suppliers in Oberkochen and Ditzingen. For investors, that means the EUV business behaves less like a normal component market and more like strategic infrastructure.
Key points
- ASML is the sole maker of EUV lithography machines.
- TRUMPF supplies the CO2 laser amplifier that turns tin droplets into EUV light.
- ZEISS SMT supplies the mirror optics, including the High-NA systems with a 0.55 numerical aperture.
- Both German firms built these capabilities on decades of experience in adjacent industrial fields.