ASML’s magic uncovered: Tech and partners behind EUV edge China can’t replicate

While China is racing to close the lithography gap with homegrown tools from Huawei-linked SiCarrier and Yuliangsheng, the reality is that extreme ultraviolet (EUV) lithography remains an entirely different universe. Machines capable of printing sub-5nm chips are not just complex—they’re the pinnacle of global scientific collaboration.

Take ASML, the Dutch firm that holds a virtual monopoly in EUV. With Intel, TSMC, and Samsung as its main clients, ASML’s dominance isn’t merely about technological leadership—it’s about an ecosystem that no country can replicate overnight.

As Focus: The ASML Way reveals, ASML doesn’t exactly build EUV scanners—it conducts them like a symphony. Instead of crafting the optics, light source, or other core modules on its own, ASML serves as the master orchestrator, coordinating a global network of over 100 top-tier suppliers.

Let’s take a closer look inside this technological marvel—unpacking the structure of ASML’s EUV system, the key enablers behind its core components, and how this intricate collaboration has become the driving force behind ASML’s dominance.

From light to chip: Inside ASML’s EUV process
As ASML explains, its EUV lithography is like carving circuits with a “nanoscale light scalpel.” Imagine trying to etch an entire encyclopedia onto a single grain of rice—ASML’s EUV machines do something similar: they use extremely short-wavelength light to “print” microscopic circuit patterns onto silicon wafers.

First, the system needs a light source. In the case of EUV, it uses a special 13.5 nm wavelength light—5,000 times thinner than a human hair. This incredibly short wavelength is what enables printing such microscopic patterns. But keep in mind that the entire process must occur in a vacuum because this type of light gets absorbed by air instantly. Without a vacuum, the precious EUV light would disappear before reaching the wafer.

Next, ultra-precise reflective mirrors are required to capture, focus, and guide the light through the system—like using a magnifying glass to focus sunlight, but with precision millions of times greater. These mirrors are polished to atomic-level smoothness to ensure no light is lost.

The light is then shaped and shines through a “stencil” called a photomask, which contains the chip’s circuit design. The light projects this pattern onto a silicon wafer, almost like shining a flashlight through a paper cutout to leave a tiny, precise shadow on the surface.

Notably, one critical advantage ASML has is its High-NA EUV technology, which uses anamorphic optics to compress patterns 4x in one direction and 8x in the other—like a smart shrinking lens. This allows a single exposure to create extremely fine features.

In contrast, DUV lithography systems (currently the most advanced technology accessible to Chinese manufacturers) must use multi-patterning—stamping the same area multiple times—to approach similar resolution, making the process slower, more expensive, and more prone to defects.

Team effort behind ASML: Key component suppliers
Twenty years! That’s how long it took ASML and its partners to perfect EUV lithography technology, according to the company. The payoff? A machine so complex it contains roughly 100,000 parts working in perfect harmony, and shipping a single unit is like orchestrating a small military operation—40 freight containers, three cargo planes, and 20 trucks, all coordinated just to get one machine from factory to fab.

And, the price tag? The latest High-NA EUV machine commands over $350 million—more expensive than a private jet, yet essential for manufacturing the world’s most advanced chips. To achieve such a feat, ASML teams up with specialized suppliers, each mastering their part, to build a machine that pushes the limits of chip-making.

ZEISS: Masters of EUV optics
Because EUV light is absorbed by air and glass, ZEISS had to create a fully mirror-based optical system that works in a vacuum. This marvel stands 1.5 meters tall, weighs 3.5 tons, and is made of over 35,000 parts.

Yet, the precision is mind-blowing: the mirrors themselves are optical masterpieces—if scaled to cover Germany, the highest bump would be just 0.1 millimeters. Each mirror has more than 100 atomically precise layers, only a few nanometers thick, to reflect EUV light with minimal loss. Making just one of these mirrors takes months, ZEISS points out.

Experts who can handle this level of precision are extremely rare. The stakes are so high that Huawei reportedly tried to lure engineers from Germany’s Zeiss SMT—the team behind ASML’s cutting-edge optics—offering salaries up to three times higher to secure their expertise in late 2024.

The dependency between ASML and Zeiss SMT is absolute. ASML has invested €1.5 billion in Carl Zeiss SMT and acquired a 24.9% stake in 2016, receiving billions in dividends since. Over the same period, Zeiss SMT’s revenue has soared from €1.2 billion in 2016 to €4.1 billion in 2024. Without Zeiss, ASML operations would come to a complete halt.

Cymer: Laser power behind EUV
Next comes ASML’s collaboration with the U.S. company Cymer on laser technology. Cymer’s excimer lasers use gases like argon fluoride (ArF) or krypton fluoride (KrF) to produce deep-ultraviolet light, but for EUV and next-generation High-NA EUV systems, they rely on Laser-Produced Plasma (LPP) technology.

In this process, high-powered lasers fire at tiny tin droplets—each the size of a coin—thousands of times per second, turning them into a plasma that emits 13.5 nm EUV light. Every variable—droplet speed, laser energy, vacuum control, and cooling design—must be precisely controlled, as even small changes can affect the performance of the entire lithography machine.

Notably, in 2013, ASML acquired Cymer to speed up the development of EUV lithography for semiconductors, while keeping it out of competitors’ hands.

Immersion breakthrough
With support from its suppliers, ASML made a major leap in chip shrinking with immersion lithography. Traditional “dry” lithography shines light through air directly onto the wafer. Immersion lithography, however, inserts a thin layer of highly purified water between the lens and the wafer. This water acts like a magnifying glass for the light, making tiny patterns easier to resolve—similar to how a drop of water makes objects underneath appear larger.

Before immersion, the industry tried shorter wavelengths (e.g., 157 nm light) to increase resolution. But calcium fluoride lenses caused double refraction, creating blurry images that couldn’t meet chip specifications. Immersion lithography cleverly sidestepped this problem by sticking with 193 nm light but using water to boost the resolution.

This technology is a modern marvel: as the lens scans across the wafer, a thin film of water must float perfectly beneath it. Not a single bubble can appear, no drop can stick to the wafer, and no mark can be left behind on the delicate patterns. And all of this happens at incredible speeds, with the wafer moving faster than the eye can follow.

This breakthrough wouldn’t have been possible without key partners. ZEISS in Germany figured out how to tweak standard lenses to work with immersion lithography, while Philips Research brought their expertise in optical recording to help design systems that could precisely move and control the water layer under the lens.

By the end of 2004, TSMC, a key ASML client, had used these early immersion systems to produce the first fully functional 90-nanometer node chips.

Why China has yet to catch up?
ASML CEO Christophe Fouquet once said China is 10 to 15 years behind in chipmaking—and the real gap may be even wider. ASML’s lead isn’t due to a single company but a complex technological ecosystem. Even if a competitor copied the exterior of a lithography machine, they couldn’t access ZEISS’s precision lenses, Cymer’s lasers, TSMC’s testing facilities, or years of fine-tuned operational data.

It’s like trying to perform a symphony by only reading the sheet music: the notes are there, but without the orchestra, the conductor, and decades of practice, the music never comes alive. This orchestration of partners, expertise, and infrastructure is what keeps ASML ahead and makes it nearly impossible for Chinese companies to catch up, at least in the near future.

Source: TrendForce, Taiwan.