Accelerated Stress Testing Handbook

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Accelerated Stress Testing Handbook is a book that is:

  • titled Accelerated Stress Testing Handbook: Guide for Achieving Quality Products;
  • edited by H. Anthony Chan, AT&T Labs, Middletown, NJ, The Hong Kong Polytechnic University, Hong Kong and Paul J. Englert, Lucent Technologies, Bell Labs Innovations, Whippany, NJ; and
  • published by IEEE Press, The Institute of Electrical and Electronics Engineers (IEEE), Inc., New York and Wiley-Interscience, A John Wiley & Sons, Inc. in 2001.

The copyright belongs to Lucent Technologies, Inc. and AT&T Corp.

  • AST (Accelerated Stress Testing). A process whereby stresses are applied to a product in excess of specified operating limits to precipitate latent flaws to the point of detection via concurrent testing. The purpose of AST is to determine the margin or robustness in a specific product. AST should be initiated during the design stage on a product that is reasonably representative of the final product. Problems found in excess of specified limits on a few design samples often translate to problems found in the customer's product within specified limits. AST may be performed at various stages in the product's life cycle: Design AST (D-AST), Manufacturing Qualification AST (MQ-AS1), Periodic Qualification AST (PQ-AST), Full-Production AST (FP-AST), and Production Sampling AST (PS-AST).
  • COTS. Commercial Off the Shelf.
  • DVT (Design Verification Testing). A process whereby stresses that are within customer-specified operating limits are applied to a product in its design stage. DVT is often viewed as a design qualification procedure. An example of a DVT specification is the Bellcore NEBS document, which contains minimal requirements that must be met by switching and transmission equipment purchased by the Regional Bell Operating Companies (RBOCs). NEBS standards exist for temperature, earthquake shock and vibration, and combined temperature and humidity stresses that may often be encountered during normal equipment operation in the field.
  • ESS (Environmental Stress Screening). A process whereby stresses are applied to a product in excess of specified operating limits without concurrent testing. Many confuse ESS with AST because ESS had been the previously used industry acronym for any type of activity that incorporated stresses beyond customer limits. ESS has merit in that it is useful for helping to monitor ongoing component quality, as well as preconditioning product before it undergoes more comprehensive AST. In the past, ESS has tended to degrade into an activity in which bad product is merely separated from good product without performing FMA/RCA and corrective action. ESS on a high volume of product may be quite expensive and difficult to economically justify for products that are large and complex products or those that are in highly costsensitive markets.
  • EST (Environmental Stress Testing). Same as Accelerated Stress Testing.
  • FMA/RCA (Failure Mode Analysis/Root Cause Analysis). The process of determining the failure modes and root causes for all product failures that have been precipitated during AST. Some FMA specialists routinely practice RCA during the act of performing FMA without explicitly referring to the acronym RCA. Others explicitly adopt the phrase RCA to emphasize the need to determine the root causes of all product failures while performing FMA.
  • FMECA. Failure Modes, Effects, and Criticality Analysis.
  • HALT (Highly Accelerated Life Testing). A term coined by Dr. Greg Hobbs in the mid-1980s to describe a process whereby stresses are applied to a new design in excess of specified limits.
  • HASS (Highly Accelerated Stress Screening). A screening process applied in a monitoring mode during manufacturing process with stress limits established with HALT from the design process. HALT is often nondistinguishable from STRIFE and AST.
  • HAST (Highly Accelerated Stress Testing). A term commonly used for establishing the reliability or qualification of component packages.
  • OLT (Operational Life Testing). A process whereby stresses that are within customer-specified limits are applied for an extended period of time to a product, either during its design stage or otT-line after full production has commenced. Rather than addressing the attainment of customer specifications as in OVf or eliminating infant mortality as in AST, OLT is targeted for the long-term life ofthe product. OLT is used as a tool to determine that the intended life ofthe product is well below the wear-out time and associated failure mechanisms for the rightmost region of the bathtub curve.
  • PEM. Plastic Encapsulated Microcircuit.
  • PPL. Preferred Parts List.
  • PPQ (Periodic Product Qualification). A standard process wherein stresses that are within customer-specified limits are applied to a product at periodic intervals ofT-line of the fullproduction process. DVT and PPQ are often specified by the customer. But the intention of PPQ is to determine whether the performance of the product that had undergone DVT has drifted due to variations in the manufacturing process, component quality, or possibly design deficiencies not detected by DVT or Design AST. PPQ must be distinguished from Periodic
  • Qualification AST (PQ-AST). Although both PPQ and PQ-AST are utilized at certain intervals after manufacturing has begun, PQ-AST employs stresses in excess of customer-specified limits to better gauge product performance margins.
  • Safety Testing. The methodology used to determine the suitability of a candidate AST regimen for usage during manufacturing. The application of stresses to product will degrade the overall life of a good product, even if it is by some small amount. During safety testing, a number of stresses and/or stress cycles that are much in excess of the manufacturing AST regimen are applied to the product. If the product's performance does not deteriorate after the application of the extreme AST safety regimen, then it may reasonably be concluded that the candidate manufacturing AST regimen will not cause any significant degradation of good product that is shipped to the customer.
  • STRIFE. The robust design process using STRESS, testing, and corrective actions to increase the life of a product. This process was originally used by Hewlett-Packard and has become a common term for the electronics industry. STRIFE is often nondistinguishable from HALT and AST.
  • Take Corrective Action. The steps taken to increase the design margin or robustness of the product once AST and FMA/RCA have been performed.
  • WCA. Worst-Case Analysis.