S 9200

A CD-SEM is a semiconductor metrology tool that uses electron imaging to measure patterned features on wafers. CD-SEM tools are typically used to check linewidth, spacing, and profile-related image information after patterning steps. CD-SEM tools belong to the metrology and inspection part of the fab rather than to a material deposition or pattern transfer step.

A scanning electron microscope forms images by scanning a focused electron beam across a sample and collecting emitted signals to build magnified views of surface features. A CD-SEM applies that imaging method to patterned semiconductor structures so measurement software can evaluate critical dimensions and related geometry. CD-SEM operation generally combines stage positioning, automated focus and stigmation, image acquisition, and pattern recognition for repeatable measurements.

CD-SEM tools are used between process modules to verify how lithography and etch steps have shaped wafer features. CD-SEM measurements commonly feed process control loops for exposure, develop, and etch conditions. CD-SEM tools therefore sit downstream of pattern creation and upstream of process adjustments based on measured feature results.

CD-SEM tools are used for dimensional measurement of patterned semiconductor features on production wafers and test structures. Typical applications include monitoring line and space patterns, contact or via features, and other structures where image-based dimensional control is needed. CD-SEM tools are also used for recipe-based repeat measurements across wafers for process monitoring and engineering analysis.