248nm-Lithography

248 nm lithography names an exposure wavelength rather than a technology node. In semiconductor manufacturing the term ordinarily refers to KrF excimer-laser deep-ultraviolet exposure. A process described as 250 nm, 180 nm, or 130 nm uses a different naming convention: those numbers identify process generations or design rules, not the photons illuminating the wafer.

The number is useful for understanding optical-material compatibility. Projection optics and resist chemistry must work at the exposure wavelength. A process developed for another spectral range cannot simply be assumed to behave identically under 248 nm illumination. The source, optics, mask, and resist therefore form a matched imaging system.

A wavelength does not place a same-sized ruler on the wafer. Lithographic resolution depends on wavelength together with numerical aperture and the process-dependent imaging factor. Their interaction determines which patterns can be separated with adequate contrast. A nominal wavelength alone cannot identify a qualified minimum line width or contact-hole size.

The historical tool record illustrates subwavelength patterning. ASML announced a KrF scanner for 130 nm design rules in 2000. This is a specific tool-development statement, not a promise that all 248 nm equipment can print every 130 nm layout. Mask structure, illumination, resist, and focus conditions remain part of the qualification.

Use this entry to disambiguate dimensions in a process description. When a document mentions both 248 nm and a smaller node, first determine whether each number describes light, a drawn feature, a pitch, or a measured structure. That reading habit prevents an apparent contradiction and makes comparisons between KrF and ArF technologies much more precise.

Sources and further reading. [ASML lithography light sources](https://www.asml.com/en/technology/lithography-principles/light-and-lasers); [ASML 130 nm KrF scanner announcement](https://www.asml.com/en/news/press-releases/2000/asml-introduces-krf-lithography-scanner-optimized-for).

Read 248 nm lithography as the wavelength-specific name for KrF exposure rather than a statement that all printed features are 248 nm.