Elektronilithografia

Elektronilithografia, or electron lithography, is a lithographic technique that uses a focused beam of electrons to create patterns on an electron-sensitive resist or to modify a substrate directly. It offers very high spatial resolution, often reaching the nanometer scale, and is typically used as a maskless method for research, prototyping, and specialized fabrication tasks.

The principle involves coating a substrate with an electron-sensitive resist, such as PMMA or HSQ. A focused electron beam, steered by electromagnetic lenses, exposes regions of the resist according to the desired pattern. After exposure, the resist is developed to reveal the patterned areas, which can then be etched or used as a template for metal deposition and liftoff. Electron exposure induces chemical changes in the resist, such as chain scission or cross-linking, and scattering of electrons within the resist and substrate creates proximity effects that can blur features at small scales. Processing typically occurs in a vacuum environment.

Equipment and methods emphasize maskless writing. An electron beam lithography system, often based on a scanning electron microscope with a field-emission gun, writes patterns directly without photomasks. Key considerations include dose control, alignment accuracy, proximity-effect correction, and resist selection. Common resists cover a range of tones and sensitivities, and multi-layer stacks enable complex processing.

Applications span nanoscale devices, quantum structures, plasmonic and photonic components, and research-grade micro- and nano-fabrication. Limitations include low throughput, high cost, sensitivity to charging and proximity effects, and the need for specialized vacuum conditions, which confine industrial-scale use but keep it essential for high-resolution research. The technique has evolved since the 1960s and remains a cornerstone of nanoscale patterning.