Method of Testing Silicon Wafers

Wafer testing is an important step of semiconductor device fabrication. The wafer testing is done by test equipment known as Wafer Prober.

Types of Wafer Testing:

             1.      Wafer Final Test (WFT)

             2.      Electronic Die Sort (EDS)

             3.      Circuit Probe (CP)

During this process, Silicon wafer is sent for die preparation. In this process, Integrated circuits present on the wafer are tested for functional defects. This is done by applying the special test pattern.

The Wafer Prober’s Role is Silicon Wafer Testing:

Wafer probe is a device used to test integrated circuits. A probe card is used for electrical testing of the silicon wafers. The Wafer is moved into electrical contact by means of Vacuum-mounted on their surface. Die electrically test the Prober to start the next test. The wafer Prober is equipped with automatic pattern recognition optics. It is responsible for loading and unloading of the Silicon wafers. It is also capable of aligning the wafers together. The Silicon Test Wafers probe exercises test circuitry on the wafer scribe lines.

Non-Contact Wafer Testing

This method is for Silicon Test Wafer. It is an alternative to mechanical probing of integrated circuits. In this method, tiny RF antennae are used to replace both the mechanical probes and the metal probe pads.

Benefits of Non-Contact Wafer Testing:

             1.      No damage is done to circuits and probe cards.

             2.      No debris is produced

             3.      Probe cards are not required.

             4.      Wireless probe points can be placed anywhere IC

             5.      The wafer probe does not exert any force on the Silicon Wafers.

             6.      Repeated probing is possible without damaging the probe points

             7.      Faster data rates are possible than with mechanical probes