Lithography is used to transfer a pattern from the mask/reticle to the layer of resist deposited on the surface of the wafer. The type of lithography that is used depends on the wavelength of radiation used to expose the resist: Photolithography (UV radiation), X-ray lithography (X-rays), e-beam lithography (electron beams) and ion beam lithography (ion beams). Furthermore, it is a process of printing on a smooth surface using photosensitive material and transferring a pattern by selective exposure to a radiation source and remove selective parts from the thin film.

It can currently print images using a wavelength of 200 nm and is continuing to develop in order to make even smaller images. For this reason, lithography is the process by which the tinier features of integrated circuits are made.
In order for lithography to take place, a photomask must be created once the resist has been applied. The photomask is made by a photographic process and developed onto a glass substrate. The mask is then aligned carefully. This can either be done through contact (the mask is on the substrate), proximity (the mask is close to the substrate) or projection (the mask is projected onto the substrate).

The resist experiences a chemical reaction during the exposure period. If it is a positive resist, the light will cause it to become polymerised. If it is negative, the reverse occurs. Once developed, a negative of the mask remains on the pattern of the resist. The wafer then undergoes a post-bake process where the sidewall angles can be altered as desired.

In order to create these thin etchings on thin films, lithography uses deep ultraviolet light. Different types of DUV lights all create different sized wavelengths. For instance, krypton fluoride produces a 248 nm spectral line while argon fluoride can make a 193 nm spectral line. Using immersion lithography, smaller sizes can be created as well.