Counting photons
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The limits · Explainer 19

How far can lithography go?

Marks lithography has made, each as its maker or lab reports it, stand on one block of silicon at one scale: from the 38 nm that Nikon and ASML each state for their own immersion scanners to a single hydrogen atom lifted off by a microscope tip. Each is in its publisher's own measure, in the order this page visits them.

38 nmArF immersion scanners, Nikon and ASML, each for its own
8 nmHigh NA EUV, ASML's stated resolution
1.7 nmone feature, Brookhaven, 2017
Scene: one block of silicon; each sample drawn at its true size relative to the others, its height at the 2:1 height to width imec calls ideal for a line. From the back: Substrate's 12 nm contacts (undated page); Nikon's and ASML's 38 nm; imec's 9.5 nm lines at a 19 nm pitch, printed on ASML's 0.55 NA scanner in their joint lab (August 2024); lines at 8.5 nm half-pitch by directed self-assembly (University of Chicago, imec and Argonne, 2019); Canon's 14 nm nanoimprint lines (2023); PSI's 7 nm half-pitch lines and its "1.9–2.0 nm isolated patterns", drawn at 2.0 nm (2024); Brookhaven's 1.7 nm feature (2017); one hydrogen atom lifted (UT Dallas, 2020). Seen from the front of the row, so the nearer samples look larger; chapter 08 shows the row from the side. Silicon atoms 0.235 nm apart: Princeton and NIST's CODATA. All sources are listed at the end.
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01 · Photons

Fewer photons.

Light arrives in photons, and a shorter wavelength means more energy in each: 6.42 eV at 193 nm, 91.8 eV at EUV's 13.5 nm (our arithmetic). So the same dose brings about 14.3 times fewer photons. OIST's Tsumoru Shintake writes that this "leads to worse LER (line edge roughness), due to random Poisson distribution."

Pick a wavelength and a dose. Each mark in the 10 nm square is one photon; silicon's atoms are drawn around it at the same scale.

One photon
91.8 eV
Photons counted
680
Against 193 nm, the same dose
14.3 times fewer
Energy and count: our arithmetic from NIST's CODATA constants, the dose over the photon's energy across 100 nm²; at 10 mJ/cm², 9,716 at 193 nm against 680 at 13.5 nm. Shintake (OIST, 2024). 6.7 nm: Johns Hopkins and others (2025). Doses marked: two research resists (Johns Hopkins and others; Victoria with Berkeley Lab, 2025) and the doses ASML rates its NXE:3800E and EXE scanners at. EUV in products since 2019: CSET. Square and atoms to scale; marks placed at random.
02 · The light source

Brighter light.

Today's EUV light comes from tin: a CO2 laser hits droplets about 25 µm across up to 50,000 times a second (ASML), the laser amplified to "tens of kilowatts of average pulse power" (TRUMPF).

Others are working on light from electrons in an accelerator, sent through an undulator of alternating magnets: KEK in Japan, xLight in the US and a Tsinghua-led team, each at its own stage. Substrate says it uses accelerators for X-ray lithography.

Light from
Tin plasma
Stage
In use
Feeds
One scanner
Tin: ASML (EUV systems; light and lasers); TRUMPF. Power: IEEE Spectrum reported ASML's sources "rated at 500 watts" (2024); no ASML page read states a wattage. Lawrence Livermore announced in December 2024 a project to test whether its BAT laser can raise the tin source's efficiency by "about 10 times" over CO2 lasers. KEK, as IEEE Spectrum reports it (2024): 20 µm infrared light from 17 MeV electrons in a hall 60 by 20 m, and 800 MeV needed for EUV. xLight: its FEL systems deliver light "to up to 16 scanners at once", starting with a first system in Albany, New York; a $150 million CHIPS award (June 2026). Tsinghua-led team: the mechanism of steady-state microbunching shown in a storage ring in Berlin with a 1,064 nm laser (Nature, 2021); a kW EUV design proposed by its first author (arXiv, 2026). Scene: KEK's hall at its stated size; the rest drawn, generic, not to scale.
03 · Past one exposure

Routes near 16 nm.

imec reached a 16 nm pitch in 2019 by multi-patterning: SAOP from 128 nm with 193 nm immersion, "three times a patterning doubling approach"; SAQP from 64 nm and SADP from 32 nm with EUV.

High NA EUV raises the NA from 0.33 to 0.55; ASML states 8 nm resolution against 13 nm. On one in their joint lab, imec printed 9.5 nm lines at a 19 nm pitch (2024) and yielded 20 nm pitch (2025), writing that the yielded limit "will therefore be larger than 16nm pitch". DSA multiplied a guide five times to 17 nm (2019).

First print
128 nm
Pitch now
128 nm
Steps
3 doublings
How spacers work: Writing with light. imec (2019, 2024, 2026: 3 to 4 masks at 0.33 NA against one at 0.55 for A14 and A10 metal). ASML: EXE:5000 and 5200B (at least 110 and 175 wafers an hour at 50 mJ/cm²), NXE:3800E; optics by ZEISS SMT. Users: SK hynix assembled one for mass production at M16 (September 2025), citing precision and density "by 1.7x and 2.9x"; Intel and ASML count over one million wafers (September 2026); Samsung plans it for DRAM by 2028; TSMC from 2030. DSA: Chicago, imec, Argonne. True scale.
04 · Nanoimprint

Printing by stamp.

Canon's FPA-1200NZ2C (October 2023) presses a mask carrying the pattern into resist "like a stamp". Canon states a minimum linewidth of 14 nm and expects 10 nm with better masks, says power consumption "can be reduced by about one-tenth compared to advanced logic exposure technology", and warns that a trapped particle can cause "destruction of the pattern on the mask itself". One went to the Texas Institute for Electronics in September 2024.

Stage
Resist laid
Minimum linewidth
14 nm
Better masks
10 nm
Canon: the launch (13 October 2023), the product page, its nanoimprint technology page (with its 2022 award shared with Dai Nippon Printing and Kioxia) and the shipment to TIE, supported by the University of Texas at Austin (26 September 2024). The machine is generic and cut open; the template's teeth and the lines are drawn at Canon's 14 nm, the spacing drawn equal. How the resist hardens is not on the Canon pages read for this one, so no step shows it. The particle is drawn.
05 · Electron beams

Writing with electrons.

An electron beam writes without a mask. IMS Nanofabrication's mask writer drives 262,144 beams at 50 keV and writes a photomask in under 10 hours; at 50 keV an electron's wavelength is 5.36 pm, about 2,521 times shorter than EUV light (our arithmetic).

Multibeam writes wafers directly with miniature columns at 5 kV, up to 25 an hour in its secure chip ID case. In laboratories, Brookhaven made a 1.7 nm feature (2017), PSI 7 nm half-pitch lines (2024).

Wavelength
5.36 pm
EUV is longer by
2,521 times
Writes with
262,144 beams, on a mask
IMS Nanofabrication and Multibeam: their own pages. Through a mask, Nikon states at least 280 wafers an hour at 96 shots for its NSR-S636E, and ASML 295 for its NXT:2100i, no condition on its page. Brookhaven (Nano Letters, 2017); PSI with Brookhaven (ACS Nano, 2024). Wavelength: our arithmetic, relativistic, from NIST's CODATA constants. Scene: a 6-inch mask on a moving stage under one column, a 300 mm wafer under miniature columns, both drawn and generic; the inset shows 32 by 32 of the beams, magnified.
06 · Atoms

One atom at a time.

A microscope tip lifts single hydrogen atoms off a silicon surface, "revealing silicon underneath" (UT Dallas, with Zyvex Labs, 2020).

Atoms can also be the beam. A 2019 paper from NTNU and the University of Bergen, among others, puts the case: an atom has "much less" kinetic energy than a photon of the same wavelength. At 13.5 nm that is 1.1 µeV for a helium atom against 91.8 eV for the photon (our arithmetic).

Separately, the company Lace says it develops "BEUV (Beyond-EUV) atom lithography systems".

Hydrogen atoms lifted, of 12
5
Helium, 13.5 nm
1.1 µeV
Photon, 13.5 nm
91.8 eV
UT Dallas (11 December 2020); Zyvex Labs, its products page (a control system for automated STM lithography); Lace, its home page (founded 2023; Norway, Spain, the UK and the Netherlands); Nesse and others, Physical Review Applied (February 2019). No page read for this one links Lace to that paper. Silicon atoms at Princeton's 0.132 nm radius, 0.384 nm apart on the surface (our arithmetic from NIST's CODATA lattice parameter); hydrogen, the tip, the mask and the atom beam are drawn, generic. Energies: our arithmetic from NIST's constants and helium-4's mass.
07 · The other way

Bigger than one field.

Nikon's and Canon's scanners list an exposure field of 26 by 33 mm; High NA's anamorphic mirrors "require an exposure field half the size" (ASML). Larger chips are joined: Nvidia's Blackwell is two reticle-limit dies, Cerebras's chip is 46,225 mm², TSMC expects a 40-reticle system on a wafer in 2029.

Canon prints 50 by 50 mm in one shot for image sensors; Nikon's maskless DSP-100 supports substrates up to 600 mm square. ASML and TSMC aim at 12-inch masks ready for production by 2033.

Shown
One field
Area
858 mm²
In fields
1.0
Nikon (NSR-S636E), Canon (FPA-6300ES6a); half field: ASML (EXE:5000), 26 by 16.5 mm ours. Nvidia (2024); Cerebras: about 54 fields; TSMC (April 2026). Canon: 50 by 50 mm (2023); 52 by 68 mm, and 100 by 100 mm in four shots (2022); 515 by 510 mm panels (2020). Nikon: DSP-100 (2025), nine times the 100 mm packages per substrate of a 300 mm wafer. Masks (September 2026): 6-inch "for decades" (Samsung and ASML); 12-inch, a pilot line by 2031, to "remove stitching constraints" (ASML and TSMC); "6x12-inch" (Intel and ASML). Areas and counts ours; one scale.
08 · The routes side by side

Side by side.

The slab from the side, at one scale. Lithography makers on this record: ASML, Canon, Nikon and SMEE, each in its own measure for its own tools. ASML: resolution 8 nm at 0.55 NA and 13 nm at 0.33 NA. Nikon: resolution ≤ 38 nm, ArF immersion. Canon: minimum linewidth 14 nm, nanoimprint; resolution ≤ 90 nm, KrF. SMEE: layers at 90, 110 and 280 nm, SSX600.

Each maker's own pages, as in the chapters above. SMEE's page is in Chinese; the translation is ours.