Answer by Mira Zaslove:
Scanning Electron Microscopes (SEMs) are much more common than Atomic Force Microscopes (AFMs) in wafer fabs today. SEMs have been around a lot longer, since 1935. Whereas AFMs are newer technology — invented in 1986 and commercialized in 1989.
SEMs are the standard for wafer manufacturing & wafer defect review in most metrology processes today. SEM's are faster, and can analyze larger surface areas compared to AFMs.
AFMs are still installed in wafer fabs, and are commonly used in nanotechnology research.
Fabs chose AFMs for a few reasons. For instance, AFMs:
- Provide 3D images. SEM provides 2D images.
- Can manipulate molecules in addition to imaging. SEM can be used only for imaging.
- Samples do not require special treatment (such as metal/carbon coatings).
- Technology provides higher resolution images.
- Can operate in liquids and work with sample sizes ranging from a few nanometers up to several micrometers.
An AFM is a great tool for visualization on the atomic scale. It provides images of both conductive and nonconductive materials. AFMs also allow for a different way to visualize molecules in 3D. AFM manufactures, such as Bruker and Veeco are investing heavily in the technology, and I expect AFM popularity to grow in wafer fabs. Already they are getting more popular in biology and biotechnology.