The introduction of scanning electron microscopes on the market is roughly contemporaneous with the rise of the semiconductor industry and microchips assembly. It is in this field that the SEM has spread the most, being recognized as a highly valuable tool in the development of manufacturing processes of devices.
Throughout the years, transistor gates have gone from a typical width of a few micrometers in the late 1960s to less than 100 nanometers in the XXI century. Not only did the SEM made it possible to see beyond the limits of the optical microscope, but its vision proved to be very practical to aid in microfabrication where it is often important to control the verticality of the deposited or engraved layers.
SEMs as Manufacturing and Damage Control Tools in Microchip Assembly
Very popular in research and development laboratories, production units, and industrial control tools. The electron probe of a SEM can also be used not to observe, but to write and manufacture, becoming electron beam lithography.
Another application of SEMs in semiconductor production units is the characterization of microparticles that contaminate the surface of wafers: the goal is to identify the cause of the contamination in order to remove it.
These particles, which can vary in size from 100 nm to 1 μm, can be detected by a specialized inspection machine that communicates the particle’s coordinates to the analytical SEM. This is then used both in the imaging mode, to produce an image of the particle at high magnification.
The image can help in the identification of the particle, but it is above everything else, the chemical characterization resulting from the wavelength analysis of X-rays that will give a clue to the cause of the contamination, which implies that the SEM is equipped with an X spectrometer