Methods for reading a feature pattern from a packaged die

摘要

Methods for tracking the identity of die after singulation from a wafer. The product chips and die include a pattern of features formed in a metallization level of a back-end-of-line (BEOL) wiring structure. The features in the pattern contain information relating to the die, such as a unique identifier that includes a wafer identification used to fabricate the die and a product chip location for the die on a wafer. The features may be imaged with the assistance of a beam of electromagnetic radiation that penetrates into a packaged die and is altered by the presence of the features in a way that promotes imaging.