EUV lithography

Extreme ultraviolet lithography (EUVL or simply EUV) is a technology used in the semiconductor industry for manufacturing integrated circuits (ICs). It is a type of photolithography that uses 13.5 nm extreme ultraviolet (EUV) light from a laser-pulsed tin (Sn) plasma to create intricate patterns on semiconductor substrates.

As of 2025, ASML is the only company that produces and sells EUV systems for chip production, targeting 5 nanometer (nm) and 3 nm process nodes, though Reuters reported in December 2025 that China had developed its own prototype EUV lithography system, China is also pursuing alternative EUV light-source approaches, including accelerator based Steady-state microbunching (SSMB) and laser-induced discharge plasma (LDP).

The EUV wavelengths that are used in EUVL are near 13.5 nanometers (nm),to produce a pattern by using a reflective photomask to expose a substrate covered by photoresist.

Image formation mechanism in EUV lithography.

  EUV multilayer of silicon-based glass spacer and molybdenum reflectors

  Absorber

  EUV radiation

  Resist

  Substrate

  Secondary electrons

EUV multilayer and absorber constituting mask pattern for imaging a line. EUV radiation reflected from the mask pattern is absorbed in the resist and substrate, producing photoelectrons and secondary electrons. These electrons increase the extent of chemical reactions in the resist. A secondary-electron pattern that is random in nature is superimposed on the optical image. The unwanted secondary-electron exposure results in loss of resolution, observable line edge roughness and linewidth variation.