Electronic devices are pervasive in many applications from computers to automobiles. Generally, electronic devices have a specified life time and are expected to not fail within that time.
Manufacturing defects may cause electronic devices to deviate from expected performance or fail at any point during the electronic device's life time. Electronic devices, therefore, are typically tested prior to shipping them to customers to ensure that the electronic devices perform within the limits set by their specification.
Defects may be categorized as intrinsic defects or extrinsic defects. Extrinsic defects are those that are directly reflected in the performance of the electronic device, and are typically caught during production testing by measuring the electronic device's performance and comparing it against the specification. Devices lost to extrinsic defects are also as infant-mortality. Certain type of manufacturing defects, however, may not manifest itself during initial testing as a normal-use failure, but may cause an application to fail later in the electronic device life. Such defects are known as intrinsic defects, and may be caught we certain types of stress testing. Devices lost to extrinsic defects are also as adult-mortality.
It is often desirable to screen out electronic devices with intrinsic defects prior to shipping them to customers to avoid system failures in applications using such electronic devices.