Lithography is one of the most important technologies in micro/nano fabrication. It transfers designed patterns onto a substrate and defines the starting point for subsequent etching, deposition and doping processes. As devices have evolved from micrometer to nanometer dimensions, lithography has also undergone continuous development.

Conventional optical lithography supported earlier microelectronic manufacturing by projecting mask patterns onto photoresist-coated wafers. As feature sizes decreased, shorter wavelengths, improved optics and more precise alignment systems became necessary. Deep ultraviolet (DUV) lithography greatly improved resolution and supported advanced semiconductor process nodes.

Extreme ultraviolet (EUV) lithography pushed patterning into even smaller dimensions. With a wavelength of 13.5 nm, EUV enables finer circuit patterns and reduces the complexity of multiple-patterning flows. However, EUV equipment is costly, system requirements are strict and mask defects, resist performance and process stability remain major challenges.

Electron-beam lithography offers very high resolution and is widely used in research, mask writing and small-batch fabrication, but its throughput is limited. Nanoimprint lithography provides another route for high-resolution patterning by mechanically transferring nanoscale features, offering potential advantages in cost and large-area patterning.

Future lithography must balance resolution, productivity, process window, cost and material compatibility. In micro/nano fabrication, lithography will continue to be integrated with advanced etching, thin-film deposition and metrology to support semiconductor, MEMS, photonic and nanodevice manufacturing.