4060 X

The Electroglas 4060 X is a probe station.^[1]

A probe station consists of a rigid mechanical frame, a motorized or manual chuck stage that moves the wafer in X, Y, and Z axes, and a probe head assembly that holds a probe card. The operator or automated system aligns the wafer to the probe tips using a microscope and camera system. Once contact is made, the test head applies electrical signals and measures responses from each die.

In operation, the chuck indexes the wafer in a step-and-repeat pattern, bringing each die under the probe array. The probe tips must make reliable, low-resistance contact with the metal pads without damaging the underlying layers. Alignment and planarity of the probe card relative to the wafer surface are critical to achieve consistent test results.

Probe stations are used after wafer fabrication is complete and before the wafer is diced into individual chips. The electrical test performed at this stage identifies known-good die, allowing defective die to be marked and discarded after singulation.

The probe station sits between the wafer-fab cleanroom and the back-end packaging line. Upstream processes include all deposition, lithography, etch, and implant steps that form the device circuitry. Downstream steps following probing include wafer dicing, die attach, wire bonding, and final package test.

The primary application of a probe station is wafer-level parametric test and functional test of integrated circuits, memory devices, and analog components. The same equipment is used for reliability studies, process-control monitoring, and failure analysis on prototype or production wafers.