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Burn-in and Reliability

Tekmos offers Burn-In and Reliability Testing services.  The requirements can vary from part to part, and Tekmos can customize these services to meet your exact needs.

Burn-in

The failure rate of integrated circuits over time follows what is called the "bathtub" curve.  There is a high rate of infant mortality initial failures.  Then the failure rate drops, only to increase at the end of life due to wear out failures.  The reliability of a part can be enhanced by providing a burn-in at elevated temperatures prior to usage.  This burn-in is typically somewhere from 40 to 160 hours in length, and is done at a temperature of between 70ºC and 125ºC.  It is important that the parts be exercised during this burn-in.  It is also good to monitor the part performance during burning, so that the time point of failures can be detected.  That data can be used to set the optimum burn-in length.

One of the major costs of a burn-in is the boards used for the burn-in.  This is a tradeoff between the cost of the sockets on the boards, the number of boards needed, and the total number of parts to be burned in.  Major manufacturers with very high volumes will invest in high quality sockets that will cost from $50 to $100 per chip.  This socket cost adds up quickly.

In addition to the oven capacity, Tekmos also has in-house design and layout capability for both the burn-in boards and driver boards (if needed).

Reliability Testing 

There are several over-lapping reliability testing specifications.  Specifically, these are the JESD47I, the AEC-Q100, and the military Mil Spec 883.  These require subjecting several lots to stresses, and then looking for failures.  Some tests are for the die, and other tests check the packages.  Because of the standardization of the packages, the die tests are the most important.  And the main die test is the HTOL, or High Temperature Operating Life.  In this test, the parts are typically operated at 125ºC for 1000 hours.  If the parts cannot be tested in the oven, the parts will be periodically pulled from the oven, tested, and re-inserted back into the oven.  Common read points are at 48, 96, 168, 250, 500, and 1000 hours. 

Parts that fail are subjected to a failure analysis.  The type of failure analysis depends on the nature of the failure.  Some failures are obvious, such as a pin breaking off.  Other failures may need to be decapsulated, and analyzed optically.  Failure analysis is engineering intensive, and Tekmos can provide that support.

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