Using a new bathtub curve to correlate quality and reliability

With few exceptions, reliability investigations focus on aging circuits that are “known good” at time zero. Both goodness (quality) and time zero are relative terms. Reliability incorporates two additional dimensions beyond quality; time and stress. This work takes a position that quality and reliability are related and can even be interchanged – depending on your point of view. A bathtub curve that measures fallout is proposed to reveal quality and reliability correlations. By assuming that quality and reliability share a relationship along the continuum of both time and stress, the relationship can be used so that present measures of quality can predict future experiences in reliability.