A scanning electron microscope (SEM) is a type of microscope where a focused beam of electrons is scanned over the sample to generate its image or to modify the sample surface with nanometre resolution (usually better than 10 nm). The sample image is most often formed by detecting secondary and backscattered electrons emitted from the impact location of the beam.
The preferential usage of SEM in the Nanofabrication laboratory is for e-beam lithography (EBL), where the resist-coated sample is selectively exposed to the focused electron beam by means of an electrostatic beam blanker and the sophisticated nanolithography attachment, allowing the preparation of very small patterns (<50 nm) on the resist surface. The stage accuracy of a common SEM is the key limitation for most lithography patterning. Therefore, the instrument is equipped with the laser interferometer stage (LIS) to allow for ultra-high resolution structuring of areas of a millimeter in size.
A Scanning Electron Microscope combined with a precise laser-based interferometric stage for e-beam patterning of areas up to 45 mm x 45 mm.
|Lithography system Raith Elphy Plus|
|Proximity effect correction software|
|Active anti-vibration suspension system|
|Sample size||up to 2" wafer size|
|Chamber vacuum||< 9e-3 Pa (< 5e-4 Pa reachable)|
|Tescan Mira 3||FEG|
|Accelerating voltage||200 V – 30 kV|
|Probe current||2 pA – 200 nA|
|View field||> 6 mm x 6 mm at WD 9 mm|
|Magnification||1× – 1 000 000×|
|Detectors (resolution)||Secondary Electron (SE) detector (1.2 nm at 30 kV)|
|In-Beam SE detector (1.0 nm at 30 kV)|
|Patterning area||45 mm x 45 mm (x 25 mm)|
|Stitching accuracy||<= 100 nm|
|Overlay accuracy||<= 100 nm|
|Raith Elphy Plus|