Metrology and analysis
Which correctly describes the principle of the scanning electron microscope (SEM)?
- AA finely focused electron beam is scanned over the sample surface, and secondary electrons and other emissions are detected to observe surface shape
- BCrystal structure is examined from X-ray diffraction
- CFilm thickness is measured from light interference
Show answer and explanation
Answer: A. A finely focused electron beam is scanned over the sample surface, and secondary electrons and other emissions are detected to observe surface shape
An SEM scans an electron beam over the sample surface and forms an image by detecting the secondary and backscattered electrons emitted. It can observe surface shape at higher magnification than an optical microscope. In semiconductor fabs, CD-SEMs, which measure pattern linewidths, are used for process control.