SU 3800 VP Electron

The Hitachi SU 3800 VP Electron is a variable-pressure scanning electron microscope (SEM) used for metrology and inspection in semiconductor fabrication. Scanning electron microscopes produce high-resolution images by scanning a focused electron beam across a sample surface, enabling the measurement and characterization of sub-micrometer features.

A scanning electron microscope operates by generating a narrow beam of electrons from an electron gun and focusing it onto the sample with electromagnetic lenses. The beam is raster-scanned across the surface, and the interaction of the primary electrons with the sample produces secondary electrons, backscattered electrons, and other signals that are collected by detectors to form an image.

The variable-pressure (VP) capability of the SU 3800 VP Electron allows the specimen chamber to operate at a controlled gas pressure, reducing charge build-up on non-conductive samples and eliminating the need for conductive coatings in many applications. The vacuum system includes a dedicated vacuum pump to maintain the required pressure levels in the column and chamber.

The SU 3800 VP Electron is used in semiconductor fabrication for in-line or off-line metrology and defect review after key process steps such as lithography, etching, deposition, and chemical-mechanical planarization. The instrument provides critical dimension (CD) measurements, profile analysis, and imaging of defects that are too small for optical microscopes.

In the fab workflow, the electron microscope typically receives wafers from inspection stations that flag defects or measurement sites, and the resulting images and measurements feed back into process control and yield management systems. The tool is also used in failure analysis laboratories for root-cause investigation of electrical or physical failures.

Primary applications of the Hitachi SU 3800 VP Electron include critical dimension measurement, defect review and classification, and process monitoring for advanced semiconductor devices. The variable-pressure capability extends its use to samples that are insulating, difficult to ground, or moisture-sensitive without requiring metal coating.

The instrument is also applied in materials science for cross-section imaging, film thickness measurement, and particle analysis. In addition to semiconductor wafers, the tool can be used to inspect and measure structures on photomasks, hard disk components, and other microelectronic substrates.