Electron microscopes designed primarily for imaging and analysis classify under SITC 87131, while highly integrated semiconductor process-control tools that incorporate electron optics as one subsystem of a larger automated inspection platform may classify under semiconductor manufacturing equipment headings. The determining factor is whether the electron-optical column is the primary functional element or a component of a broader automated system.

Yes — atomic force microscopes (AFM) and scanning tunneling microscopes (STM) are non-optical instruments that use physical probe interactions rather than light or electrons for imaging, and they generally classify within the non-optical microscope heading. Importers should confirm the specific HTS subheading with a customs broker, as the precise classification can affect applicable duty rates.