Test Performance Evaluation

In order to better understand and continually improve the manufacturing test process, it would be helpful to have a definitive measure of the “quality” of the test sets used. One method of measuring test quality might be to simply monitor the field reject rate - the number of parts returned or reported to the manufacturer as faulty. However, this is a crude measure for several reasons. Circuits can be damaged by a number of post-manufacture phenomena such as electrostatic discharge effects, poor encapsulation or wire bonding, etc. Also, on very complex circuits, some faults may never be detected if the corresponding portion of circuitry is not used by the consumer.