E-beam lithography refers to a specialized technique used to create striking patterns required by the modern electronics industry for integrated circuits. This creation of distinctive designs is made possible due to the electronics’ petite spot size. Resolution in optical lithography is usually limited by the wavelength of light that is used for exposure. The electron beam features such a small wavelength while the diffraction no longer defines the lithographic resolution.
The core advantage of E-beam lithography lies in the ability to draw custom patterns. The technology can directly write prints with sub-10nm resolution. Electron beam lithography systems applied in commercial applications feature a dedicated E-Beam system that is very expensive.
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How Are E-Beam Systems Classified?
The Electron beam lithography systems are classified according to the accelerating voltage, the processing chamber pressure, and the electron gun mounting position. These characteristics affect the scale, the manageability of the equipment, and the welding processes that can be performed. Let’s have a look at each of the three classification criteria work.
Accelerating Voltage — High Voltage Vs. Low Voltage E-Beam Lithography Systems
The accelerating voltage largely determines the output of an electron beam. Therefore, the E-Beam lithography systems with an accelerating voltage of between 100 to 150 kV fall under the high-voltage classification. In contrast, those of about 30 to 60 kV are classified as low voltage.
The high-Voltage e-beam lithography systems can weld steel materials with a thickness of about 0.1 and 200 millimeters. Also, these systems can weld aluminum alloys with a thickness of about 0.1 to 300 millimeters.
If melting on none specialized applications, the low voltage devices are more comfortable to use. Therefore, the low voltage devices are commonly used in different fields, including in the electronic component industry.
Processing Chamber Pressure — High Vacuum vs. Low Vacuum
The second major characteristic of the electron beam lithography systems is that the e-beam lithography melting process can be performed in the vacuum processing chamber. However, the e-beam lithography companies have introduced electron beam machines capable of welding without using a perfect vacuum.
Generally, the processing chambers with a pressure of up to 0.067 Pa are considered high-vacuum enclosures. On the other side, the processing chambers that feature forces of up to 6.67 Pa are classified as low-vacuum chambers. The processing chamber pressure varies depending on the application. The volumes are increasing, with some equipment boasting an internal volume of several hundred cubic meters.
The general-purpose high-vacuum exhaust devices include those applied in oil diffusion pumps, the mechanical booster pumps, and the oil rotary pumps. The low vacuum devices include those involved in the mechanical booster pumps and the oil rotary pumps.
Lithography companies have introduced devices that feature scroll pumps and molecular turbopumps. These devices offer less noise, minimum vibration, and heat thanks to the technologies that allow energy efficiency.
Electron Gun Mounting Position — The Fixed Electron Gun vs. Moving Electron Gun
The e-beam emitting gun can be mounted either on the inside or outside the processing chamber. The processing chamber is generally categorized as fixed or movable for the externally attached electron gun and comes with a superior sliding seal. For the selected electron gun devices, the welding position is changed by moving the base material. On the other side, the welding position is adjusted by moving the electron gun. Therefore, the moving electron gun devices feature a satisfying stroke of several meters that enable the welding at a wide variety of positions.
In the e-beam lithography systems with the electron gun mounted inside the processing chamber, the electron gun is attached to a robot capable of simultaneous control along five axes.
Conclusion
The e-beam lithography systems can be applied in different industrial applications. The industrial applications include Cryo-electric devices, Opto-electronic devices, quantum structures, transport mechanism studies of semiconductor/ superconductor interfaces.