Electron Beam Lithography [EBL] is the process of drawing a custom pattern on the surface that is coated with a resist (electron-sensitive film).
When exposed to electrons, the surface of the material will behave either of the two ways-
- The material becomes significantly soluble, which enables its removal by immersing it in a solvent.
- Material cross-links which makes it resistant to solvents. Thus, allowing the removal of surrounding resistance.
How does Electron Beam Lithography [EBL] work?
The first development of Electron beam lithography dates back to the late 1960s. It was done by modifying the structure of SEMs or scanning electron microscopes. In EBL, the resist layer is patterned by directly scanning it electronically with an electron beam. Photolithography and EBL more or less share a similar thing working principle.
It's straightforward and efficient. A narrow beam of focused electrons is scanned across a substance covered in resist or electron-sensitive material. Depending upon the areas that are exposed or not exposed, the resistance is removed through development. Contemporary EBL systems have impeccable focus depth of more than hundreds of nanometers.
Components of Electron Beam Lithography [EBL] System
There are five central parts of the Electron beam lithography system. They are-
- An electron gun or a source that supplies electrons
- An electron column that focuses and shapes the electron beam
- A wafer handling system for automated feeding wafers to the system and uploading them after processing
- A mechanical stage that's utilised for placing the wafer under an electron beam
- A computer system controlling other components
Electron lithography and optical lithography employ negative and positive electron resists.
Electron Beam Lithography [EBL] has gradually become a highly suitable modern alternative type of lithography. One of the most favourable factors of EBL is that its cost-efficient and its applications have been very beneficial in the industry.
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Advantages of Electron Beam Lithography
EBL is used to manufacture tiny nanostructures with high accuracy and reliability at a resolution that's less than 10 nanometers.
There's no requirement for a photomask to do the same.
It is a suitable patterning method for the production of stamps utilised for nano-imprint lithography and patterning method for product development.
FAQs on Electron Beam Lithography [EBL]
Q1. Why should one choose Electron Beam Lithography [EBL] over photolithography?
Ans. The advantage of using Electron Beam Lithography [EBL] over photolithography is that EBL allows for resolution as high as 20 nm. It can also directly print intricate or complex custom patterns on the wafer. Lastly, it's a comparatively more flexible technique than photolithography, meaning it's simpler to work with different kinds of materials and patterns.
Q2. Name some disadvantages of Electron Beam Lithography [EBL]?
Ans. Like any other process, Electron Beam Lithography [EBL] has its own set of disadvantages too.
- Blanking or deflection error
- Shaping error
- Backscattering calculation error
- Slower than Photolithography
Q3. What factors control the resolution of Electron Beam Lithography [EBL]?
Ans. There are three factors that affect the resolution of Electron Beam Lithography [EBL] are-
- Spot size
- Electrostatic repulsion happens due to the interaction of two electrons
- Scattering of electrons off the resistor substrate
Q4. What are the industrial applications of Electron Beam Lithography [EBL]?
Ans. Electron Beam Lithography [EBL] is a versatile technique that has a wide range of industrial applications.
- Optometrist-electronic devices.
- Microsystem techniques.
- Cyro-electric devices.
- Transport mechanism studies of superconductor or semiconductor interfaces.