EUV Mask Blanks and Pellicles

Mo/Si multilayer · low-expansion glass · pellicle · AGC, Hoya, Mitsui Chemicals

Every EUV mask starts as a blank from one of two Japanese companies, AGC or Hoya, and most are protected by a pellicle from a third, Mitsui Chemicals. The first challengers are Korean: S&S Tech's EUV blanks entered testing on a Samsung 4nm line in 2026, and FST is scaling carbon nanotube pellicles.

An EUV mask blank and pellicle, layer by layer, with who supplies each. Pellicle membrane: Mitsui Chemicals in volume; FST and S&S Tech of Korea developing. Tantalum-based absorber, ruthenium cap and 40 to 50 molybdenum and silicon pairs: deposited by AGC or Hoya, both Japanese; S&S Tech samples in test at Samsung since 2026. Low thermal expansion glass substrate: AGC, Corning and SCHOTT. No layer is made in volume in China. WHO MAKES EACH LAYER OF AN EUV MASK FRAME, A FEW MM GAP Pellicle membrane MITSUI CHEMICALS IN VOLUME Absorber, tantalum-based PATTERNED LATER BY THE MASK SHOP Ruthenium cap AGC OR HOYA Mo/Si multilayer, 40 to 50 pairs AGC OR HOYA; S&S TECH IN TEST Low-expansion glass, 6.35 mm AGC, CORNING, SCHOTT LAYER THICKNESSES NOT TO SCALE 2 Volume makers of EUV blanks AGC AND HOYA, BOTH JAPANESE; NO PUBLIC SHARE SPLIT SAMSUNG BUYS MOST OF ITS BLANKS FROM HOYA (THE ELEC, 2026) SOME US VOLUME MADE ABROAD
EUV blank makers
AGC, Hoya
Multilayer
40 to 50 Mo/Si pairs
Defect limit
About 0.1 per cm²
Main pellicle maker
Mitsui Chemicals
Light lost, 90% pellicle
19% (computed)
Hub
Materials

The blank

An EUV Blank Is a Mirror With No Room for a Buried Defect

EUV light at 13.5 nm is absorbed by almost everything, so an EUV mask reflects light instead of passing it. The blank is a mirror: a slab of glass that barely expands with heat, coated with 40 to 50 alternating layers of molybdenum and silicon about 3.5 nm thick each, a ruthenium cap against oxidation, and a tantalum-based absorber that the mask shop later patterns. The stack reflects about two-thirds of the light at its peak.

The EUV mask blank stack
LayerWhat it doesHard part
Low-thermal-expansion glassHolds the pattern flat as the mask heats in the scannerFlatness and near-zero expansion; polished to below 0.1 nm roughness
Mo/Si multilayerReflects 13.5 nm light by constructive interferenceOne buried defect shifts the phase of reflected light and can print on every wafer
Ruthenium capProtects the multilayer from oxidation and cleaningFew nanometers; must survive repeated cleans
AbsorberPatterned by the mask shop to block light where there is no circuitThinner, higher-absorbing materials needed for High-NA EUV

A production blank needs fewer than about 0.1 phase defects per square centimeter, measured with EUV light. That is why the business is closed: the deposition tools, the actinic inspection and years of defect learning are all needed at once. How the finished mask is written and sold is on Photomasks and Reticles.

Blank makers

Two Japanese Companies Make Every EUV Blank in Volume

AGC and Hoya, both of Japan, make the EUV blanks used in volume. Neither publishes its share, and estimates in circulation disagree on which is larger; Samsung buys most of its EUV blanks from Hoya, according to The Elec. AGC says it is the only maker that produces both the glass and the coating, raised its EUV blank capacity about 30% by 2025 with support from Japan's trade ministry, and targeted mask blank sales above 40 billion yen for 2025.

EUV blank makers and challengers
CompanyHomeStatus
AGC (AGC Electronics)JapanVolume supplier; makes its own glass; capacity up about 30% by 2025
HoyaJapanVolume supplier; main EUV blank source for Samsung (reported)
S&S TechSouth KoreaSent EUV blank samples to Samsung in March 2026; in test on a 4nm line for less demanding layers; orders could take six months to over a year (The Elec, April 2026)
Applied MaterialsUSHas shown blank deposition technology; not a volume supplier
Corning, SCHOTTUS, GermanyGlass substrates only, not coated blanks

Pellicles

A Pellicle Costs Light Twice Because the Mask Reflects

A pellicle is a membrane on a frame a few millimeters above the mask, so a particle that falls on it is out of focus and does not print. For deep ultraviolet masks it is a routine polymer film. For EUV it has to be a free-standing film tens of nanometers thick that lets most of the light through, survives the heat of a 400 W to 600 W source and resists the hydrogen in the scanner.

EUV masks reflect light, so the light passes through the pellicle twice, once on the way in and once on the way out. A pellicle that transmits 90% in one pass lets through 81% after two, a loss of 19% of the light reaching the wafer; at 95% one-pass transmission the loss is 10%. A particle that lands on the pellicle sits a few millimeters above the pattern and is too far out of focus to print. MASK: REFLECTIVE MULTILAYER WITH PATTERNED ABSORBER PELLICLE, TENS OF NM In: pass 1 Out: pass 2 Particle on pellicle OUT OF FOCUS, DOES NOT PRINT LIGHT REACHING THE WAFER AFTER TWO PASSES No pellicle 100% 90% film 81% 95% film 90% COMPUTED: ONE-PASS VALUE SQUARED.

Because the mask reflects, light crosses the pellicle twice. A film that transmits 90% in one pass delivers 81% of the light, so a fab gives up about a fifth of its exposure dose, which it pays back in scanner time (computed). That is why some EUV layers have run without pellicles, and why fabs decide layer by layer.

Pellicle makers

Mitsui Chemicals Leads; Carbon Nanotube Films Are Next

EUV pellicle makers
CompanyHomeTechnology and status
Mitsui ChemicalsJapanMain commercial supplier; production licensed from ASML in 2019; silicon-based membranes; above 90% transmission reported
Mitsui Chemicals with imecJapan, BelgiumCarbon nanotube pellicle for sources above 600 W; partnership signed December 2023; target introduction 2025 to 2026
FST (Fine Semitech)South KoreaCarbon nanotube membranes made on Canatu reactors; commercial production license October 2025; second reactor ordered August 2026 for 2027 delivery
CanatuFinlandSupplies the carbon nanotube reactors and process; royalties from licensees
S&S TechSouth KoreaPellicle frames and membranes developed with Samsung (patents reported)
TSMCTaiwanMakes some pellicles in-house (reported)

Carbon nanotube films conduct heat better than silicon films of the same thickness, so they are the main candidate for the higher source powers coming with newer low-NA and High-NA EUV scanners. See ASML EUV Scanner for source power by generation.

Inspection

Only Lasertec Inspects Blanks With EUV Light

A phase defect buried in the multilayer is invisible to visible light and electron beams but scatters EUV light at the wafer. Finding it requires actinic inspection, at 13.5 nm, and Lasertec of Japan is the only commercial maker of actinic blank and mask inspection tools. Its lead times limit how fast mask shops and blank makers can add capacity. See Metrology and Inspection Equipment.

China

China Has No EUV Blank Supply and No Scanner to Use One

China has no EUV scanner in production and no EUV blank, pellicle or actinic inspection supplier. Its fabs pattern leading layers with deep ultraviolet immersion and multi-patterning instead, so the EUV blank chain is one China does not yet need; the gap matters only once a domestic EUV scanner exists. See Lithography Equipment for SMEE and the domestic scanner programs.

Sites

Only the Glass Has US Volume

  • Made in US
  • Made abroad
EUV blank, glass, pellicle and inspection sites
SiteLocationMakesStatusUS status
AGC ElectronicsKoriyama, Fukushima, JapanEUV mask blanks; capacity raised about 30% by 2025OperatingMade abroad
HoyaJapanEUV and DUV mask blanksOperatingMade abroad
S&S TechDaegu, South KoreaEUV blank samples in test at Samsung; DUV blanksTestingMade abroad
CorningCanton, New YorkULE low-expansion glass for EUV substratesOperatingMade in US
Mitsui ChemicalsIwakuni-Otake Works, JapanEUV pellicles under ASML licenseOperatingMade abroad
FST (Fine Semitech)South KoreaCarbon nanotube pellicle membranes on Canatu reactorsScalingMade abroad
LasertecYokohama, JapanActinic blank and mask inspection toolsOperatingMade abroad
Placeholder: other blank, glass and pellicle plants

Record

Page Record

Covers
The EUV blank stack, blank makers and challengers, pellicles and the two-pass light loss, pellicle makers, actinic inspection, China, and production sites
Sources
AGC release on EUV blank capacity (April 27, 2023); The Elec (S&S Tech blanks at Samsung, April 16, 2026); Mitsui Chemicals and imec release (December 14, 2023); Canatu release on FST (August 24, 2026); company site lists; light loss through the pellicle computed from one-pass transmission
Last verified
October 2026