DUV immersion lithography (ArF 193 nm)

Why the concentration exists

Immersion lithography works by filling the space between the projection lens and the wafer with highly purified water, which raises the effective numerical aperture above 1.0. ASML introduced this approach for DUV systems in 2003, and current immersion tools reach a numerical aperture of 1.35. The technique was first proposed in the 1980s and gained industry attention in 2002 when 157 nm lithography ran into technical problems. ASML publicly announced the industry's first immersion system, the TWINSCAN XT:1250i, in December 2003. The water medium lets 193 nm light resolve features below 45 nanometers, with a theoretical resolution limit of 36 nm at 1.35 NA.[13][4][14][16]

The physics of high-NA immersion at 193 nm imposes severe demands on optical materials, which must have a large bandgap to remain transparent in the deep ultraviolet. Candidate materials include MgO, Lu3Al5O12 (LuAG), HfO2, and ZrO2, while sapphire is eliminated due to its low refractive index at 193 nm. ASML's NXT:2050i uses a 1.35 NA catadioptric projection lens that achieves production resolutions down to 40 nm in C-quad configuration and 38 nm in dipole configuration. The system produces 295 wafers per hour and delivers 2.5 nm cross-matching on product overlay. These combined optical and throughput demands create a high qualification barrier for any new entrant.[5][6][15]

What the evidence shows

Who supplies it

ASML dominates the immersion lithography market with nearly 99% share, having shipped 131 immersion DUV tools in 2025. The company's leading 193 nm immersion platform is the mature XT:1900 series, introduced over a decade ago. ASML plans to ship approximately 130 immersion systems globally in 2026, matching 2025 levels. The current production workhorse is the TWINSCAN NXT:2050i, designed for 300 mm wafer volume production at advanced nodes.[20][2][7][15]

ZEISS Semiconductor Manufacturing Technology supplies the DUV lithography optics used at 193 nm, while Cymer provides the ArF immersion light sources at 193 nm wavelength. On the Chinese side, Shanghai Micro Electronics Equipment (SMEE) has reportedly sold around ten units of its SSA800 series, which targets 28 nm immersion DUV lithography. SMEE has also patented methods to improve chip pattern quality, and a separate Shanghai state-owned enterprise, Aisheng Na Electronic Technology Group, has absorbed personnel from both Yuliangsheng and SMEE.[1][3][21][11][18]

What it depends on, and what depends on it

Through multi-patterning, 193 nm immersion extends well beyond its single-exposure resolution floor. SMIC demonstrated 7 nm production using DUV multi-patterning for Huawei's Kirin 9000S, according to TechInsights. Chinese domestic immersion DUV machines target 28 nm manufacturing using single exposure, and through multiple patterning could support production at 7 nm and potentially 5 nm nodes. SMEE's 193 nm ArF immersion DUV system is considered capable of 28 nm semiconductor manufacturing, and with advanced multi-patterning techniques could potentially support processes down to 7 nm. This multi-patterning capability is what keeps immersion relevant as EUV emerges for the most critical layers.[8][22][12]

The immersion tool itself combines a 193 nm catadioptric projection lens with a high-purity water delivery system between the lens and the wafer. The optical materials must have a large bandgap to remain transparent in the DUV, which restricts the pool of viable compounds. The deep ultraviolet optics operate at 193 nm wavelength, and the ArF immersion light sources provide the patterning illumination. These subsystems together represent decades of accumulated process and component knowledge that any new entrant must replicate.[15][16][5][6][1][3]

Where it sits in the stack

What would break it

China has begun manufacturing domestically developed immersion deep ultraviolet lithography machines, with the developer identified as Shanghai Yuliangsheng Technology, a startup with ties to Huawei and the SiCarrier equipment group. A state-backed company in Shanghai has begun mass-producing these machines, with first units due for delivery in 2026 to SMIC, Hua Hong Semiconductor, and ChangXin Memory Technologies. Output targets around five machines in 2026 and roughly 20 in 2027. Yuliangsheng's 2027 target of 20 machines would represent roughly 12% of ASML's anticipated capacity.[9][7][17]

The Chinese DUV machines rely on critical components supplied by vendors outside China, most notably from Japan. SMIC has been testing a Yuliangsheng immersion lithography system since September 2025, with the system resembling ASML's Twinscan NXT:1950i from 2008 in its overall architecture. SMEE has also been developing a 193 nm ArF immersion DUV system, and the two Chinese efforts together represent the most credible challenge to ASML's near-monopoly. The qualification timeline for these domestic tools will determine how quickly they can displace imported systems.[19][10][21][12]

What to watch

Mass production of the Yuliangsheng tool is targeted as early as 2027. The Yuliangsheng immersion DUV system is designed for 28 nm-class fabrication technologies, with multi-patterning potentially extending it to 7 nm. Industry experts estimate at least two years of qualification work before high-volume deployment, placing that milestone in late 2027 at the earliest. The goal is to integrate domestic immersion DUV lithography machines into production lines starting in 2027, after their qualification.[23][10][12][7]

Related nodes

Sources

1. zeiss.com
2. asianometry.com · 2023-02-14T01:28:13
3. cymer.com · 2024-10-04T17:50:37
4. spie.org
5. researchgate.net · 2015-07-23T00:00:00
6. scispace.com
7. tomshardware.com · 27 July 2026
8. tomshardware.com · 2025
9. semiwiki.com · July 27 (Reuters)
10. tomshardware.com · 17 September 2025
11. digitimes.com
12. semiwiki.com · Jun 28, 2026
13. asml.com · 2003
14. asml.com · December 2001
15. asml.com
16. en.wikipedia.org · 2015
17. techtimes.com
18. en.sedaily.com · 2026.07.29
19. hothardware.com · Tuesday, July 28, 2026, 01:30 PM EDT
20. finance.biggo.com
21. cryptobriefing.com · September 2025
22. techstartups.com · 2026-07-27
23. kucoin.com · September 2025