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It Doesn’t Have To Be Difficult To Use Electron Beam Lithography. These 10 Pointers Should Be Read

It Doesn’t Have To Be Difficult To Use Electron Beam Lithography. These 10 Pointers Should Be Read

For several purposes, EBL may be utilized to generate photolithography masks. EBL takes longer since it requires you to write the pattern in a specific sequence. To cut down on writing time, a variety of approaches are employed. In industrial environments, EBL devices often employ extremely high acceleration voltages (50 kV).

Let’s look at the most crucial tips which make Electron Beam Lithography Easy!

Take a look at these under-the-radar ways for lithography businesses to improve their electron beam lithography systems:

How Do you Figure out How Fast You’re Going?

The dose required to overcome resistance increases as the acceleration voltage increases. Why? Because forward-scattered electrons transmit energy to the resistor more efficiently at lower acceleration voltages (10 kV), clearance dose requirements are decreased, but at the expense of a larger incident beam spot and rougher line surfaces.

Furthermore, depending on the developer type and development process, the amount of clearance necessary varies considerably.

Aperture Size Selection for Collimation

To collimate and current-limit an electron beam, you can utilize a beamline with interchangeable apertures. A collimating aperture with a diameter of 120 microns was used to increase the beam current. More electrons from the filament were able to reach the sample as a result of this. In an electron microscope, a collimating aperture in the electron column is a typical feature. It’s essentially a way to change the numerical aperture of a beam. Lower apertures result in a smaller numerical aperture, resulting in a larger depth of focus.

The High Current Mode Must be Turned On.

Raith offers a “high current” option that modifies the condenser lens’ focusing properties on generating a narrower, more parallel beam. The beam current is nearly doubled at this level. Due to the effects of space charge, the ultimate resolution will be slightly reduced, but the depth of focus will be improved because of the narrower, parallel beam. Using a collimating aperture with a 120-meter diameter and a 10 kV acceleration voltage, we measured a beam current of 6.8 nA.

Set the Size of the Field.

A standard writing field is 100 m by 100 m in size. Because we used such a large write field, we were able to replicate the pattern even with a 100-fold reduction in the number of write fields (the maximum is 2000 m 2000 m). As a result of the sample stage moving and settling being faster, the sample stage moving and settling time will be decreased by 100. There are some disadvantages to using bigger write fields. Because the pattern generator’s digital-to-analog converter (DAC) has a limited addressable resolution, it’s important to reduce the minimum step size. The addressable step size of the EBL is still rather small for write fields of 1000 m 1000 m.

In a write field, there are two methods for moving the beam around: raster scan and vector scan. Although it is the most basic method, it takes the longest to finish. As the beam passes overexposed areas, it begins to unblank. The vector scan is more technically challenging since it leads the beam to each region that has to be exposed and only scans over the components that need to be exposed. While utilizing a vector scan might save time, it is very dependent on the pattern being created, so bear that in mind while using it.

The E – LiNE design program employs the GDSII Raith lithography module. For integrated circuits, the GDSII format is extensively used. Bitmaps and other pattern file formats, as well as other file kinds, can be imported. You may import a bitmap using the “bitmap as reference” function of the e LiNE program. You can use the “bitmap as reference” format while using the line or meander modes. As the laser scans the whole write field, un- and exposure blanking will occur.

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