Extreme ultraviolet lithography
Summary of key features
The following table summarizes key differences between EUV systems in development and ArF immersion systems which are already widely used in production today: The different degrees of resolution among the 0.33 NA tools are due to the different illumination options.

Extreme ultraviolet lithography

Section Title: Summary of key features
Table Section Text: The following table summarizes key differences between EUV systems in development and ArF immersion systems which are already widely used in production today: The different degrees of resolution among the 0.33 NA tools are due to the different illumination options.

EUV	ArF immersion

Wavelength	13.5 nm	193 nm

Photon energy	92 eV	6.4 eV

Light source	CO2 laser + Sn plasma	ArF excimer laser

Wavelength bandwidth	5.9%	<0.16%

Secondary electrons produced by absorption	Yes	No

Optics	Reflective multilayers (~40% absorbing per mirror)	Transmissive lenses

Numerical aperture (NA)	0.25: NXE:3100 0.33: NXE:33x0 and NXE:3400B High NA (0.55): in development	1.2, 1.35

Resolution spec Note: k1 defined here as resolution/(wavelength/numerical aperture)	NXE:3100: 27 nm (k1=0.5) NXE:3300B: 22 nm (k1=0.54), 18 nm (k1=0.44) with off-axis illumination NXE:3350B: 16 nm (k1=0.39) NXE:3400B: 13 nm (k1=0.32)	38 nm (k1=0.27)

Flare	4%	<1%

Illumination	Central angle 6 degrees off axis onto reticle	On axis

Field size	0.25 and 0.33 NA: 26 mm X 33 mm High NA: 26 mm X 16.5 mm	26 mm X 33 mm

Magnification	0.25 and 0.33 NA: 4X isomorphic High NA: 4X/8X anamorphic	4X

Ambient	Vacuum hydrogen	Air (exposed wafer area underwater)

Aberration control (including thermal)	None	Yes, e.g., FlexWave

Illumination slit	Arc-shaped	Rectangular

Reticle	Pattern on reflective multilayer	Pattern on transmissive substrate

Wafer pattern shift with reticle vertical position	Yes (due to reflection); ~1:40	No

Pellicle	Available, but has issues	Yes

Wafers per day (Note: depends on tool and dose)	1000	6000

# tools in field	36 (all 0.33 NA tool models)	> 400

Sentence(s)

The EUV spectrum has a wavelength of 13.5 nm.

final_sentence: The EUV spectrum has a wavelength of 13.5 nm.