The birth of SEM3300, the "KING" of Tungsten Filament Scanning Electron Microscopy

Tungsten filament Scanning Electron Microscopy (SEM) is cost-effective, easy to maintain, relatively simple to operate, and requires less space, making it easy to use by the general public. However, for a long time, the resolution of tungsten filament SEM has been at a standstill, making it difficult to achieve the user's pursuit of higher resolution.

CIQTEK recently introduced the SEM3300, a tungsten filament scanning electron microscope that has successfully increased its 20 kV resolution to 2.5 nm, a 16% improvement over ordinary tungsten filament electron microscopes!
3 kV resolution of 4 nm, a 2-fold improvement!
1 kV resolution of 5 nm, a 3-fold improvement! 

It redefines the industry standard of tungsten filament scanning electron microscopy by significantly outperforming ordinary tungsten filament electron microscopy in all voltage bands!

CIQTEK SEM3300

The following three pictures are real pictures of standard gold particles at different voltages, each particle size is around 300nm, with sharp edges, rich details, and distinct heights.

 Images of standard gold particles at different voltages taken with SEM3300

It is well known that the diaphragm material in lithium batteries has poor electrical conductivity and tiny pores, and a low-voltage, high-resolution field emission electron microscope must be used to capture better images.

Figure a shows the effect of conventional tungsten filament SEM, the details are blurred and unclear. SEM3300 accomplishes this difficult task effortlessly, the septum pores are clearly visible at 1 kV, and the edges of the pores are sharp enough for septum inspection (Figure b).

 
Figure a: Lithium battery septum photographed by conventional tungsten filament SEM, with blurred and unclear details 

Figure b: SEM3300 photographed lithium battery diaphragm, diaphragm pores clearly visible, the sharp edge of the hole

How the CIQTEK SEM3300 is redefining tungsten filament SEM?

The CIQTEK SEM R&D team analyzed the main factors limiting the resolution of tungsten filament SEM:

The tungsten filament emission structure is a 3-electrode structure with a cathode, gate, and anode. At low acceleration voltage, the filament brightness will be significantly reduced by the space charge effect and electron source aberration. At low landing energy, the chromatic and diffraction aberrations caused by energy dispersion are large, resulting in a large beam spot. In order to ensure the collection efficiency of the lateral secondary electron detector, the working distance is relatively large and the objective magnification is not large enough.

In response to these problems, CIQTEK added a 10 kV high voltage tube from the anode directly to the objective lens pole shoe inside the mirror barrel, which we figuratively call a high voltage tunnel. Here is an example of 1 kV landing energy.

At the upper end of the high-voltage tunnel: a strong electric field of 11 kV is formed between the cathode and the anode, and the field strength of the filament surface is extremely high. A large number of hot electrons overcome the limitation of the space charge effect on the beam brightness and significantly increases the beam brightness.
At the other end of the high-voltage tunnel: the tube mouth and the lower pole shoe of the objective lens form a 10kV deceleration field electric lens, which forms a complex mirror with the magnetic lens, thus effectively reducing the spherical aberration coefficient and chromatic aberration coefficient of this complex mirror.

In addition, the electron detector in the mirror barrel can collect most of the accelerated secondary electrons at a very short working distance with a collection efficiency of up to 90%, which is several times higher than the signal strength of the side ET detector of a conventional tungsten filament.

Combining all of these innovations, the CIQTEK SEM3300 finally breaks the decades-old ceiling of tungsten filament limiting resolution in the full voltage range, redefining tungsten filament SEM.