UF 60 A

A wafer prober is an electromechanical test system that makes temporary electrical contact between a semiconductor wafer and an electronic tester. Probers exercise the individual circuits on a wafer before those circuits are cut apart and packaged. The tool is a standard piece of equipment in semiconductor device testing and is used wherever die must be screened at the wafer level.

Wafer probers hold a wafer on a movable chuck and align the die to the needles of a probe card. The probe card is mounted above the chuck and connects the probe needles to the test head of an automatic test system. The chuck positions the wafer beneath the probe card and steps from die to die so each circuit can be tested.

Probing uses an optical alignment system to locate the die positions on the wafer. After alignment, the chuck raises the wafer to press the die's bond pads into the probe needles. Machines of this class repeat the contact-and-test sequence across the entire wafer and often include cassette handling to feed wafers automatically.

Wafer probers operate between front-end wafer fabrication and back-end assembly in integrated circuit manufacturing. At this stage, the prober contacts each circuit so known-good die can be separated from defective ones before dicing.

The probe step generates the first complete electrical test of the individual circuits on the wafer. Results from probing are used for yield analysis and process monitoring before the wafer moves to packaging.

Wafer probers are used in final electrical testing of integrated circuits at the wafer level. Wafer probers are also used for parametric testing of test structures fabricated alongside production die.

Probing supports production test, process development, device characterization, and failure analysis. The machines handle wafers of silicon and are applied to both logic and memory device testing.