What is Test?

Testing of ICs in mass production is a screen between the factory and the customer.

It uses acceptable overhead (throwing away good units) to deliver an acceptable defect level (bad shipments, usually customers want 0 dppm, but for consumer electronics, 300 dppm used to be acceptable) at the customer end.

A good test implementation will use a tester of reasonable cost (whose resources are limited) to achieve the required yield with an acceptable test time.

The challenge for the test engineer is to design the test hardware (cost not critical because very few units are produced - max of about 30) to provide parametrics with required accuracy, with electrical and mechanical robustness and a test program that achieves the yield goals with acceptable cost.