Probe performs the first of several tests each component must pass before being shipped to a customer. To test the die, a probe card is positioned over each wafer. Probe needles on the card touch corresponding bond pads on the die. The needles act as transmitters, electronically sending information to and receiving information from the die's memory.
A computer map of the wafer is generated showing the results for each die, and a database of information is created.
Parametric tests are also performed at Probe to define variations in the fabrication process and to check the reliability of the parts.
The tests performed in Probe save packaging and test costs, help increase yields by allowing for repair of some of the non-functional die, and generate important data for design and product engineers and yield analysis and enhancement.
After the wafers in a lot are tested, they are sent to Assembly. In some cases, unpackaged die and wafers are sorted and prepared for external customers who package the die according to their own specification.