Must-Know Techniques Of Electron Beam Lithography

Must-Know Techniques Of Electron Beam Lithography

The e-beam technology allows the development of photo-lithography masks that have huge application diversity in multiple fields. The electron beam lithography asks you to write the patterns more effectively. You can ease the process; there are various techniques available with EBL lithography that reduce the writing time. 

Common Yet Useful Techniques On Electron Beam Lithography Resolution

Let’s explore what all techniques can be related to electron beam technologies and how they are functional on the practical level. Below are the complete details:

#1. Increased Acceleration Voltage

You need to find out how much initial acceleration was there and to what range it was increased while executing the electron lithography. As the electron resistance keeps on decreasing, the value of voltage acceleration increases. The forward electrons come with more efficient working and energy transfer. They have the capacity to transfer energy at lower acceleration voltage. Hence, the electron stream gets broader and requires very low effort. The clearance dose is dependent on the product’s substance and development process. 

#2. Collimate Size and Current limit the Beam 

The electron beam current density must be decreased or limited to some extent. The collimation can be easily carried out by allowing multiple apertures. The usual collimation aperture of the electron beam is 120 microns in diameter, and the same needs to be decreased. More is the current limit; more will be the electron flow in the process. The electron microscope has an inbuilt collimation feature, and you can set the numerical value of the aperture. It has been advised that for an aperture of 120 m diameter, the numerical value will be 1-2 m. 

#3. Speed of Electron Beam 

You can control the speed of the electron beam in ion beam lithography with the help of software. It uses eLine design software and GDSII format to import the necessary files with the Raith lithography module. The file format can be others as well, like bitmap, etc. You just need to choose the right reference mode of the file. The electron beam will be as per the mentioned files and write field. The value can be changed anytime, and the electron beam can be controlled.

#4. Enable Higher Current Mode

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The lens focusing properties can be managed and altered to enable the high current modes. Once this is changed, the electron beam becomes smaller and more parallel. This can increase the exposure and enable a high current mode. Although there can be a slight downfall in the final resolution due to the effects of space-charged particles, still the parallel Beam will boost the depth of focus. If we use the collimating aperture of 120 m diameter and voltage of 10 kV, the current density will be around 7 nA. 

#5. Enable Write Mode

In the electron beam melting process, there is a single write field that can be used to move the Beam around multiple sorts of scanning options. These are raster scans or vector scans. While the raster scan is one of the simplest methods, vector scan is a bit more complicated. But, the former one is very time-consuming. In a raster scan, the electron beam is scattered on the surface and covers it everywhere.

While the vector scan allows the electron beam to reach each sort of area that needs to be exposed and leaves out the rest of them, that’s the reason why it is faster and saves a lot of time. The better pattern we are creating, the greater the chances of faster scanning. 

#6. Enable Field Size and Dimensions 

The usual size of the writing field in electron beam lithography is 100 m, and that’s very average. If we see the maximum size, it goes up to 2000 m. So as we keep on increasing the writing field, it starts multiplying as the multiplication of 100 folds, and the number of involved write fields decreases easily. The sample stage will move ahead and faster, the overall time of moving and settling of the sample stage can be reduced by 100 times, and efficiency will be increased without much effort. 

We hope the above shared information proves helpful to you.

Author: Nina Mdivani