Wafer sort (probe test)
Beginner
Testing each chip with tiny needles while it is still on the round slice of silicon it was made on, before the slice is cut up.
Novice
The first production test. A probe card with fine needles touches each chip’s pads while the chips are still on the wafer, before it is cut up. Failing chips are marked and never packaged.
Expert
Limited by probe contact, power delivery and speed, so it may run a reduced or slower test set. Its main job is to keep bad dies out of packages; for multi-die packages it is the screen that defines a known-good die.
Explained in Design for test (Design Flow).
See also: Final test (package test), known-good die.