Extreme ultraviolet (EUV) photolithography: the technology that underpins the future of chips

When discussing the future of chips, the most powerful mobile phones, or the coming artificial intelligence, there's one term that always comes up in the conversation: extreme ultraviolet photolithography, also called EUV lithographyThis technology has become both the bottleneck and the driving force behind the advancement of the world's most cutting-edge semiconductors.

Although the concept sounds very technical, understanding what EUV lithography is, how it works, who controls it, and what impact it has on geopolitics and the global economy is key to understanding why there is a chip shortage, why some countries are fighting over these machines, and why companies like ASML, TSMC, Samsung or Intel They have become strategic on a global scale.

What is extreme ultraviolet (EUV) photolithography?

In the semiconductor industry, EUV lithography refers to a photolithography technique that uses extreme ultraviolet light with a wavelength of 13,5 nanometers, that is, in the region of so-called soft X-rays within the electromagnetic spectrum. This wavelength is much shorter than that of visible light (400-700 nm) and also than that of deep ultraviolet (DUV) lithography, which typically works at 248 nm (KrF) or 193 nm (ArF).

The use of this very short wavelength allows define much smaller and denser patterns on silicon wafers, which translates into the possibility of integrating billions of transistors onto a single chip. Each new generation of lithographic nodes (7 nm, 5 nm, 3 nm, 2 nm, 1,8 nm…) comes with faster chips, with greater capacity and a significantly lower energy consumption.

Photolithography, whether with DUV or EUV, basically consists of project a geometric pattern onto a wafer coated with a photoresistThis photopolymer is altered when selectively illuminated through a mask (or photomask), so that the exposed areas become soluble or insoluble, allowing microscopic structures to be etched onto the substrate. With EUV, the physical principle is the same, but the technical complexity of the system increases dramatically.

A key fact is that The wavelength of 13,5 nm is more than ten times smaller than that used in ArF scanners (193 nm). Thanks to this, EUV equipment can print details smaller than 20 nm, something that conventional lithography could only achieve with very complex, slow, and expensive multi-pattern techniques.

How EUV light is generated and handled

Producing 13,5 nm light in a controlled manner and with the necessary power is one of the major technical challenges of this technologyIn current systems, a high-power CO₂ laser source It fires two extremely rapid pulses at a tiny, moving droplet of liquid tin. The first pulse deforms the droplet; the second, more intense pulse vaporizes it, forming a plasma.

This hot tin plasma emits EUV radiation, which is captured by a collector mirror and sent to the rest of the optical system. This entire process repeats at an impressive rate, around 50.000 times per secondto generate a light flow intense enough to maintain an industrial production rate.

Since EUV radiation is absorbed by air, the path it travels from the source to the wafer must be inside a high-quality vacuum chamberFurthermore, any dust particle or any minimal irregularity in the optical components can ruin the projected image, so the requirements for cleanliness, mechanical stability, and vibration control are extreme.

Reflective optics, impossible mirrors, and special masks

Unlike DUV lithography, which uses transmission lenses and transparent quartz masks, EUV lithography is based on fully reflective opticsThe reason is simple: virtually all materials, including the glass used in traditional lenses, absorb light of 13,5 nm.

Instead of lenses, EUV systems use a system consisting of ultra-precision multi-layered mirrors These mirrors guide and focus the beam from the source to the wafer. They are made up of dozens of alternating layers of different materials deposited with atomic precision, allowing them to reflect EUV radiation with the highest possible efficiency within the limits of physics.

However, even with these sophisticated solutions, each mirror absorbs a significant portion of the light it receives. ASML's current systems utilize at least two condenser mirrors and six projection mirrors, and together, Approximately 96% of the emitted light is lost.This requires the EUV source to be extraordinarily bright so that, after all reflections, enough energy reaches the wafer.

The masks are also different: instead of being transparent plates with opaque areas, EUVs use reflective masksThese are also multi-layered, with patterns engraved on them as reliefs and coatings that modulate reflection. Any defect in the mask or the mirrors immediately results in printing errors and, therefore, defective wafers.

What makes ASML's EUV machines so special?

The EUV photolithography machines manufactured by the Dutch company ASML are, literally, some of the most complex machines ever builtA single first-generation EUV unit integrates over 100.000 parts, some 3.000 cables, 40.000 bolts, and around two kilometers of internal electrical wiring. And all of this is perfectly coordinated by extremely sophisticated control software.

This level of complexity makes the equipment gigantic: each machine occupies a space similar to that of a city bus And it requires multiple auxiliary modules, cooling systems, vacuum equipment, and precision electronics. Furthermore, they are not shipped fully assembled; they are transported in hundreds of crates and assembled and calibrated on-site at the customer's factories.

Much of ASML's success lies in its network of technology partners. Approximately 90% of the components of these machines come from other manufacturers distributed throughout the world. Among them, two key names stand out: Cymer and ZEISS, both absolutely essential for EUV lithography to function as it should.

ZEISS's contribution: optics at the limits of physics

The other key partner is ZEISS, the historic German high-precision optics company. ZEISS designs and manufactures the EUV equipment reflective optical components from ASML, from the initial collecting mirrors to the complex projection optics that transfer the pattern to silicon.

These mirrors must work with a wavelength of 13,5 nm maintaining uniformity and precision of the extreme waveform. The flatness of the surface is such that, if a mirror were enlarged to the size of a country, the irregularities would be less than the height of a blade of grass. Any minimally noticeable deviation would ruin the pattern and render the wafer unusable.

In addition to mirrors, ZEISS is involved in developing sensors and actuators that correct in real time The system detects minor deformations, displacements, or vibrations that may occur during operation. It also provides software that continuously monitors the optical system's behavior and ensures it remains within exceptionally tight tolerances.

High-NA EUV: the new generation that breaks the 3nm barrier

After several years consolidating the first generation of EUV equipment, ASML has taken the next step with its machines of high numerical aperture, known as High-NA EUVThe most representative commercial model is the Twinscan EXE:5200, considered today to be the most advanced lithography equipment in the world.

The key to these new systems lies in the increase in the numerical aperture of the optical system: it goes from NA = 0,33 in current EUV equipment to NA = 0,55 in the High-NAIn broad terms, this allows for printing even finer details at the same wavelength of 13,5 nm, improving the resolution of the patterns transferred to the wafer.

Thanks to this improvement, High-NA EUV equipment opens the door to manufacturing integrated circuits beyond the commercial threshold of 3 nmallowing nodes around 2 nm and even the 18A (1,8 nm) technology that Intel plans to use. Furthermore, ASML has optimized the mechanical and wafer handling systems so that a single High-NA machine can process more than 200 wafers per hour, which is critical for maintaining a competitive cost per chip.

The price of a High-NA machine is estimated to be around $300 million per unitThat's roughly double the price of a first-generation EUV, which costs around 150 million. Even so, for manufacturers who want to stay ahead of the curve, it's practically a must-have investment.

A technological monopoly with enormous geopolitical impact

In the EUV lithography market, there is one undeniable fact: ASML is the only manufacturer capable of producing these machines on an industrial scale. This monopoly translates into an unprecedented position of power within the semiconductor value chain.

Giants like TSMC, Samsung, and Intel rely on ASML's EUV equipment to produce their most advanced chips. Approximately a quarter of the income ASML's revenue already comes directly from the sale of EUV systems, not including service contracts, upgrades, training and maintenance.

This technological domain also has a clear geopolitical dimensionTensions between the United States and China have placed EUV lithography at the center of the debate. Washington has pressured the Netherlands to limit the export of its most advanced machines to China, aiming to curb the Asian country's access to cutting-edge nodes. Meanwhile, Japanese manufacturers like Canon are exploring alternatives such as nanoimprint lithography (NIL), theoretically capable of producing 2nm nodes, but for now, EUV remains the de facto standard at the technological forefront.

Why EUV lithography is so important for today's chips

The relevance of EUV lithography is best understood by looking at the devices we use daily. Many of the smartphones, smartwatches, video game consoles and computers more recent, both in their chip design As in their manufacturing, they use CPUs, GPUs, SoCs and memories manufactured with 7nm, 5nm or lower nodes, where EUV is already essential for certain layers of the process.

Samsung, for example, announced the use of EUV to manufacture its 7nm chips called 7LPPThese technologies will be fundamental for enabling high-capacity 5G networks, advanced artificial intelligence applications, the Internet of Things, and autonomous driving systems. According to the company, the switch to EUV allows for up to a 50% reduction in energy consumption, a 20% increase in performance, and a roughly 40% decrease in footprint compared to previous multi-pattern ArF-based technologies.

Companies like Apple, Huawei, and other major chip designers also rely on them. Foundries that use EUV to be able to offer faster and more efficient devices. And it's not just about raw power: reducing power consumption and heat is crucial for mobile phones, laptops, and servers to perform better within reasonable thermal limits.

Key advantages of EUV lithography versus DUV

The first major advantage of EUV lithography is the possibility of print much smaller featuresWith such a short wavelength and a suitable numerical aperture, structures can be manufactured that, for the same chip size, multiply the number of transistors available by several times compared to previous technologies.

This translates into chips with greater processing capacity, more integrated memory And, above all, significantly lower energy consumption per operation. For data centers, communications networks, or large-scale AI applications, this improvement in energy efficiency has a dramatic impact on operating costs.

The second advantage is process-related: EUV allows reduce the number of lithographic steps required to achieve the same pattern. While ArF and multi-pattern methods could require three or four different exposures to achieve a complex structure, EUV often only requires one. This simplifies the manufacturing flow, improves yield, and can reduce the cost per chip in the medium term.

Furthermore, by being able to concentrate more functionality on a smaller surface area, it opens the door to increasingly integrated system-on-a-chip architectures, with blocks of CPU, GPU, AI accelerators, memory, and specific logic coexisting on the same piece of silicon—something only viable when a very high integration density.

The current drawbacks and limitations of EUV

The main obstacle to EUV lithography is, undoubtedly, the astronomical cost of the machines and the infrastructure they require. We're not just talking about equipment that easily exceeds one hundred million dollars per unit, but also entire plants designed around them, with advanced cleanrooms, very powerful power supplies, and extremely complex support systems.

This means that only a few top-tier foundries and IDMs—TSMC, Samsung, Intel, and a few others—can afford to deploy EUV on a large scale. Much of the rest of the industry continues to use DUV lithography, which is more affordable and perfectly adequate for its intended purpose. less advanced chips such as those employed in automotive, basic consumer electronics, and many industrial systems.

In addition, technology still drags technical challenges Important factors include: the power of the light sources, the lifespan of the optical coatings against such high-energy radiation, the complexity of the reflective masks, and the need to maintain high productivity without triggering defects per wafer—issues that continue to be refined generation after generation.

ASML, Intel, Samsung and TSMC: a chain of cross-dependencies

The collaboration between ASML and major chip manufacturers is not just a client-supplier relationship. Intel, for example, invested around $4.000 billion in ASML in 2012 to support the development of the first EUV machines, ensure priority access to the technology, and actively participate in its development.

ASML is currently delivering its first High-NA EUV systems to strategic customers. The first Twinscan EXE:5200 system has been delivered to an Intel factory in Hillsboro, California, a move that aligns with the company's roadmap to reach its 18A (1,8 nm) node in the second half of the decade. close the gap with TSMC and Samsung in the race for technological leadership.

Samsung and TSMC, meanwhile, are vying for both available EUV production capacity and priority in ASML shipments. Export delays—exacerbated by the COVID-19 pandemic—have occasionally forced readjust roadmaps, postpone pilot production of nodes such as 3nm and reorganize the allocation of wafers among high-value customers such as Apple, Qualcomm or large car manufacturers.

This entire ecosystem means that the availability of EUV systems, the delivery rate of ASML, and the adaptability of Cymer, ZEISS, and other suppliers have become decisive factors in determining Which companies and which countries are setting the pace? in the next-generation semiconductor industry.

Extreme ultraviolet photolithography has established itself as the key to keeping Moore's Law alive, manufacturing 7, 5, and 3 nm chips, and venturing into 2 nm and below, but also as a scarce and extremely expensive resource controlled by a handful of players. Understanding its physics, its challenges, and its market helps us see why our mobile phone, our car, or the cloud we use daily actually depend on a few gigantic machines scattered around the world and on the ASML and its partners' ability to continue pushing the boundaries of EUV technology.

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Alberto Navarro

I am a technology enthusiast who has turned his "geek" interests into a profession. I have spent more than 10 years of my life using cutting-edge technology and tinkering with all kinds of programs out of pure curiosity. Now I have specialized in computer technology and video games. This is because for more than 5 years I have been writing for various websites on technology and video games, creating articles that seek to give you the information you need in a language that is understandable to everyone.

If you have any questions, my knowledge ranges from everything related to the Windows operating system as well as Android for mobile phones. And my commitment is to you, I am always willing to spend a few minutes and help you resolve any questions you may have in this internet world.