The fast progress nanotechnology and nano-science in the last few decades indebted to electron beam lithography (EBL) a powerful top-down nanofabrication approach. As the name suggest this method is a lithography method functions by electron illumination of the e-beam resist (electron sensitive polymers) followed by development and removal, deposition of the desired materials and final etching. The typical steps of an EBL process for fabrication of a metallic disk over a silicon wafer is demonstrated schematically in the following figure.
Since the wavelength of the electron are very small, the resolution of the method is very high and it enables fabrication of the structure in few 10th of nanometer which are unattainable in optical lithography. In contrast to chemical approaches, EBL can allow the designer to precisely control the structure geometry, size and the spatial distribution of the patterned structures. Accordingly, the EBL is the primary technique in order to develop and fabricate nano-size pattern as structures such as metamaterials, metasurfaces, nano-circuits and miniaturized sensors among others.
The typical process step is very similar to that of optical lithography but there is no need of masking. In other words, the cost of instrumentation (>1.0M$) and its relatively low throughput limit its application in large scale fabrication process. However, its precision and high control over the geometry makes it an inevitable technique for state-of-the-art nano-dimension devices and advanced research laboratory.