TABLE OF CONTENTS Before discussing the flaw-stimulus relationships, two defect definitions need to be clarified, namely, patent defect and latent defect.
A patent defect is a flaw which has advanced to the point where an anomaly actually exists or it can be defined in terms of an out-of-tolerance, or a specification, condition which can be readily detected by an inspection or a test procedure [1].
Patent defects represent the majority of the defect population in an equipment and are readily detected without the need for stress screens. A small percentage of defects however, cannot be detected by conventional means. Such defects are termed latent defects.
A latent defect or a flaw is some irregularity due to manufacturing processes or materials which will advance to a patent defect when exposed to environmental or other stimuli [1].
A latent defect is characterized as an inherent or induced weakness or flaw in a material which will manifest itself as a failure in the operational environment. A subset of this is a design defect which should be corrected during maturation.
Both patent and latent defects are introduced into the product during fabrication, assembly, handling and test operations. The patent defects pass through various assembly stages until they are detected by a test or inspection of sufficient thoroughness and are subsequently eliminated from the product. When good quality control test and inspection procedures are applied, all but the most subtle patent defects should be detected and eliminated prior to shipment. Some examples of...
