Alessi REL 6100

Wafer probers are used to make electrical contact with devices on a semiconductor wafer before the wafer is separated into individual die. Wafer probers typically position an array of probe needles or a probe card against the device pads to measure electrical characteristics. Wafer probers are commonly found in semiconductor test floors and characterization laboratories.

Wafer probers hold the wafer on a chuck that moves in planar and vertical axes with sub-micron precision. A wafer prober uses a microscope or camera to align the probe tips to the target pads on the die. A wafer prober applies electrical signals through the probe contacts and measures responses through the same contacts.

Automatic wafer probers can index across the entire wafer, stepping from die to die to test each device sequentially. The probe station may include chuck heating or cooling stages for temperature-dependent testing. The system may also incorporate a probe card, which contains many needles that contact multiple pads simultaneously.

Wafer probing occurs after the completion of wafer fabrication and before the wafer is diced into individual chips. The probing step allows defective devices to be identified and mapped, so that only known-good die are assembled. Probing is also used for process monitoring and development.

Wafer probers are applied to characterize discrete semiconductor devices, integrated circuits, and MEMS devices. Wafer probers are used for DC and radio-frequency testing, as well as for reliability and failure analysis. Wafer probers also support parametric testing during process development.