Puma 9130 Darkfield Defect

The KLA Puma 9130 is a darkfield defect inspection system.^[1][2]

The Puma 9130 falls under the metrology and inspection category of semiconductor manufacturing equipment.^[1][3]

A darkfield imaging architecture images scattered light against a dark background, so particles and defects appear as bright spots on the image.

The system acquires images of the surface, and defect detection is performed by comparing the signal from inspected regions against a reference. A reference die, cell, or database pattern is typically used to distinguish real anomalies from the geometric patterns of the device itself.

Darkfield inspection relies on a clean, low-background surface signal, so it is best suited to films and substrates that are not densely patterned; brightfield inspection is generally used for the most complex patterned layers.

A darkfield inspection tool of this class typically operates alongside brightfield inspection, review scanning electron microscopy, and optical review tools. The darkfield tool performs high-speed sampling of a lot or wafer population, and suspect locations are subsequently imaged at higher resolution for classification and root-cause analysis.

Typical applications include contamination monitoring on incoming wafers, post-clean and post-strip checks, film-defect monitoring after deposition, and general defect sampling on product wafers.

Darkfield inspection is also widely used in the manufacture of photomasks and other substrates where small particles can cause printable defects, because a single particle on the mask surface scatters light strongly against the dark, otherwise clean background.