What Is an Electron Beam Lithography System?
Electron beam lithography systems are used to draw circuit patterns for LSI (large-scale integration) circuits.
Electronic devices such as cell phones and PCs contain semiconductor electronic circuit components called LSI.
After designing an LSI circuit, the circuit pattern must be burned onto a reticle (equivalent to film in silver halide photography) with an electron beam.
At this time, dimensional and positional errors must be kept within 2 to 5 nm.
The electron beam lithography system is used to burn the circuit pattern onto the reticle with this accuracy.
Uses of Electron Beam Lithography Systems
Electron beam lithography systems are used in the baking process of ultra-fine circuits used in LSIs.
LSI is an essential component of electronic devices. For example, LSIs are used as components in cell phones, PCs, game consoles, cameras, and other devices.
LSI designs change depending on the application, and there are LSIs suitable for various fields, such as communication devices, power supplies, acoustic processing, image processing, sensors, and AI.
In order to accommodate a wide range of LSI design patterns, circuit patterns designed by CAD (computer aided design) are burned onto reticles using an electron beam lithography system.
Principle of Electron Beam Lithography Systems
The LSI process is largely divided into design, front-end process, and back-end process.
Circuit patterns are drawn on reticles in the design stage, highly integrated electronic circuits are formed on silicon wafers in the front-end process, and semiconductors are cut from the wafers, fixed in place, and sealed in the back-end process.
In the design stage, the fine circuit pattern of the LSI is conventionally burned onto the reticle by optical transfer, similar to silver halide photography.
However, visible light has a wavelength of approximately 400 nm to 700 nm, so circuits finer than the wavelength of light cannot be burned onto the reticle.
As LSIs have become larger and larger over time, the subject of research was how to concentrate numerous circuits on a small LSI.
This is where the electron beam came in.
The wavelength of an electron beam is 0.012 nm at an acceleration voltage of 10 kV, so it can draw much finer circuit patterns than light.
However, to draw highly detailed circuit patterns, a high-precision electron beam lithography system is required.
The electron beam lithography system was developed for this purpose.
There are two types of electron beam lithography systems: the raster scanning system (which arranges “dots” like pixels on a TV) and the vector scanning system (which fills in shapes such as circles and rectangles).
This electron beam lithography system enables the drawing of high-definition circuit patterns on reticles.