traceability

Traceability is the ability to track every chip from raw wafer through fabrication, packaging, and test to the end customer, enabling quality investigation, failure analysis, and targeted recalls. Traceability levels: (1) Wafer-level—wafer ID, lot ID, process history (every tool, recipe, chamber, operator); (2) Die-level—wafer map position, probe test results, defect inspection data; (3) Package-level—package lot, assembly date, bond wire/solder type; (4) Unit-level—individual device serial number, test results, bin assignment; (5) Customer-level—ship date, destination, customer lot assignment. Traceability data flow: (1) Wafer fab—MES records every process step with tool ID, time, recipe; (2) Wafer sort—probe results linked to wafer map (x,y position); (3) Assembly—die-to-package mapping, assembly lot tracking; (4) Final test—test results per unit linked to package and die history; (5) Shipping—serialized tracking to customer. Key identifiers: (1) Lot ID—group of wafers processed together; (2) Wafer ID—unique per wafer (laser scribed); (3) Die ID—x,y coordinate on wafer; (4) Device serial—unique per packaged device (e-fuse or laser mark). Traceability systems: MES (manufacturing execution system), OCAP (out-of-control action plan), RMA (return material authorization) databases. Applications: (1) Failure analysis—trace field failure back to specific wafer, lot, process conditions; (2) Containment—when defect found, identify all potentially affected product; (3) Root cause—correlate failures with process excursions; (4) Continuous improvement—data-driven process optimization. Automotive requirements: IATF 16949 mandates full traceability, AEC-Q100 requires lot-level tracking. Recall capability: if systematic defect discovered, trace forward from process excursion to all affected chips in the field. Traceability is non-negotiable for quality-critical applications and provides the data foundation for zero-defect manufacturing programs.