KLA
The KLA 2351 is an inspection system used for wafer defect detection. The KLA 2351 supports 8 inch and 12 inch wafer sizes. The KLA 2351 uses a wavelength illumination of 370–720 nm, covering visible and UV bands.[1][2]

Wafer size
Wafer Transfer System
Optics
370~720 nm[1]
The KLA 2351 is a wafer inspection system for semiconductor metrology and inspection.
Wafer inspection is performed during manufacturing to find defects and monitor process excursions before the flow advances to later steps.
The KLA 2351 is used for wafer defect inspection on semiconductor production wafers.
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Die-to-die comparison is typically faster and works well for masks with repeating patterns, while die-to-database mode can identify defects even in non-repeating areas by comparing the captured image against the designed layout. The sensitivity level achievable depends on the optical resolution of the system and the quality of the reference data.
Many advanced reticle inspection systems support multiple illumination modes such as transmitted, reflected, and even polarized light to enhance contrast for different defect types and absorber materials. The choice of illumination mode is selected based on the mask blank and pattern characteristics.
Throughput varies significantly with the mask size, required resolution, and defect sensitivity settings. In general, higher sensitivity inspections take longer. Machines of this class are designed to balance speed and sensitivity for production environments, with automated handling to minimize operator intervention.
Sophisticated image processing and machine learning algorithms are employed to filter out nuisance defects that are not actually pattern errors or contaminants. The system allows tuning of detection thresholds and can learn from user feedback to reduce false counts without compromising real defect capture rate.
The following facts about the 2351 are absent from this record as of this revision. First-hand knowledge or a citation closes a gap; every submission is reviewed before publication.
No publicly documented production dates or lifecycle milestones (introduction, end of production, EOL) for the 2351 are on record.
Answerable by: OEM historical records or a trade-press announcement
No publicly documented variants, configuration options, or revision breakpoints of the 2351 are on record.
Answerable by: an OEM product catalog or an engineer who ordered or specified the tool
The control-system platform and OS era of the 2351 are not on record.
Answerable by: an engineer who operated it or OEM installation records
No publicly documented failure modes or field errata for the 2351 are on record.
Answerable by: a field service engineer, process engineer, or maintenance technician
The process node or technology generation of the 2351 is not on record.
Answerable by: an OEM datasheet or a fab qualification report
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Last updated Oct 3, 2026.
The KLA .204 PSL Wafer is an 8-inch NIST-traceable reference wafer compatible with Surfscan 6xy0 and Sp1 particle counters.
KLA .496 PSL Wafer is an 8-inch NIST traceable wafer stated to be capable on Surfscan 6xy0 and SP1.
The KLA .498 PSL Wafer is a NIST traceable reference wafer.