Electronics Reliability Testing using HALT/HASS.pdf
The first part of this book addresses the need to use testing methods and discontinue FPM that is still the major “tool” of reliability development in the electronics industry. FPM is being used by many companies, especially military equipment contractors, as a key guide to developing a reliable product, although there is no supporting evidence of benefit. These probabilistic prediction methods do not produce or help to produce a reliable electronics system from the fact that most failures before technological obsolescence are due to one or more assignable causes, and not intrinsic wear out mechanisms. The first part of the book details the history of existing failure prediction methodologies, also the limitations of these existing methodologies using real field reliability data.
The author presents a new approach, using early discovery testing. The methodologies described are derived from HALT (Highly Accelerated Stress Test) and HASS (Highly Accelerated Stress Screening), terms coined by the late Dr Gregg Hobbs. The new school of reliability development is a major paradigm shift because the process shifts the process from attempting to quantify reliability in the time domain (lifetime) whereas HALT references the strength of materials and empirical operational limits. The later chapters provide case study evidence, support and some guidance for electronics reliability engineers on using empirical step stress methods such as HALT to develop reliable, robust assemblies. Applications of this new methodology are described fully.