Wafer probe or test is the first time that chips are tested to see if they function as they were designed to do. There are three basic tools used as a set to perform this operation.

First, the wafer prober is a material handling system that takes wafers from their carriers, loads them to to a flat chuck, aligns and positions them precisely under a set of fine contacts on a probe card. Mostly, this test is performed at room temperature, but the prober is increasingly being required to also heat or cool the wafer during test.

Secondly, each input-output or power pad on the die must be contacted by a fine electrical probe. This is done by a probe card, whose job is to translate the small individual die pad features into connections to the tester.

Thirdly, the functional tester or automatic test equipment (ATE) is capable of functionally exercising all of the chip's designed features under software control. Any failure to meet the published specification is identified by the tester and the device is cataloged as a reject. The tester/probe card combination may be able to contact and test more than one die at a time on the wafer. This parallel test capability enhances productivity at wafer probe.

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