The E-beam lithography, abbreviated EBL or e-beam lithography is the process of transferring a pattern onto the surface of a substrate. The method involves first scanning a thin layer of organic film, referred to as resist, on the surface using a tightly focused and precisely controlled electron beam. The process also involves selective removal of the exposed or the non-exposed regions of the resist in a solvent.
Lithography companies have deployed the E Beam lithography successfully. In this post, we reveal why E Beam lithography has been successful.
- E beam Lithography allows Patterning of Very Small Features
One of the reasons why Ebeam lithography has been successful is that researchers have used the technology for patterning very small features with dimensions of sub micrometer down to a few nanometers. The approach involves either covering the selected areas of the surface using a resist, or exposing the otherwise resist-covered areas. Therefore, researchers process the exposed regions further for etching or thin-film deposition while the covered parts are protected during these processes.
The Electron Beam Lithography scans the focused beam of electrons in a patterned fashion across the surface. This allows the creation of very small structures like the integrated circuits or the other nanostructures.
- The Technology Features shorter Wavelength Compared to Wavelength of Ultraviolet Light
Therefore, through shorter wavelengths of accelerated electrons, the technology allows defining of much smaller diffraction limited features. In contrast with photon-based lithography, the electron lithography offers a higher patterning resolution because of using the shorter wavelength associated with the 10-100keV electrons involved.
- No Diffraction Limitation
In E beam lithography, the minimum obtainable feature dimension is not limited by diffraction. This is because the quantum mechanical wavelength of the high energy electrons is exceedingly small. Therefore, in EBL, the resolution is related to the spot size of the focused beam, but it is also affected by the forward scattering of the e-beam inside the resist. Diffraction is a severe issue that limits the accuracy of pattern transfer. Therefore, if other lithography systems are causing diffraction, you need to consider an alternative approach, which, e beam lithography, ensures greater accuracy. Therefore, if other lithography technologies result in diffraction, you should go for electron lithography, which is the best alternative.
- Uses E-Beam Instead of Visible Light Beam
The electron-beam lithography scans the focused beam of electrons in a patterned fashion across a surface. Through this process, the focused beam creates the very small structures like the integrated circuits of the nanostructures. This approach utilizes the E-Beam instead of a visible or UV light beam in the lithography process. However, just as the UV technology, energetic electrons can change the chemical characteristics of the solubility of the resist enabling a selective removal of the exposed or the non exposed regions of the resist.
- A Flexible Technique
The E-Beam Lithography technology is a flexible technique that works with various materials. Therefore, using the technology, you can achieve almost an infinite number of patterns. Besides, the Ebeam lithography can print complex computer generated patterns directly on the wafer. The electron beam lithography uses different electron beam sources. The alternative electron beam sources include thermionic emitters, which feature electrons released due to thermal energy. The second alternative is photo emitters, which occur due to incident radiations. The electron beam lithography can also use field emitters as an electron beam source. The field emitter is applicable due to the applied current and quantum mechanical property of electrons.
Conclusion
Electron beam lithography involves direct writing lithography process using a focused beam of electrons to form patterns by material modification, material deposition, or material removal. Therefore, electron beam lithography is one of the preferred patterning methods used for product development. In electron beam lithography, a resist layer is directly patterned by scanning with an electron beam electronically. Modern electron beam lithography systems feature an outstanding depth of focus and can correct for large scale height variations.
Electron beam technology is however, a pricey technology compared to conventional optical lithography technologies. Besides, the maintenance cost is high, making the systems a reserve for the well-established research institutions and the laboratories. Traditionally, the optical lithography systems monopolize the microelectronics fabrication because it is an easy processing, parallel, and material compatible technique.
