Wafer testing

Wafer testing is a step performed during semiconductor device fabrication after back end of line (BEOL) and before IC packaging.

Considerable information about device performance is obtained from WPT using structured typically provided in the scribe lines.

The WFT "yield" is recognized as the key test in determining the economic outcome of the entire fabrication process.

Historically, non-passing circuits were marked with a small dot of ink in the middle of the die, today this information is stored in a file, named a wafermap.

This is not usually the case, since the removal of defective dies saves the considerable cost of packaging faulty devices.