Accelerated Mode Test for Automotive Electronics 960393
The role of tests employed in design verification and production is traditionally one which is static. Such tests are created in which ‘good’ signals are applied to the device-under-test (DUT); these tests are considered complete and are frozen once the DUT is released to production or production begins.
However, the effort to reach zero parts-per-million (PPM) defect manufacturing rates demands more than such static tests can provide. Tests must evolve to support design, component, and process variability to support zero PPM. Test developers must strive to achieve maximum fault coverage at minimal test times. The real fault spectrum of a DUT, with which a manufacturing operation deals, evolves with process and design maturity over time. Additionally, there are field conditions which stress DUTs which cause them to fail and be returned, suggesting that the internal factory bounding of fault spectrums is too narrow. Static tests often are unable to cope with these two external realities.
To both speed the development of tests which test better and more thoroughly, and to allow tests to properly expand and contract (minimizing test time), the use of accelerated ‘corner,’ stress, and degraded signal tests are suggested. These tests emulate the traditional static tests, plus emulate full functional and behavioral operation including those which are stressed in the field. The overall technique combines these harsh parametric and functional tests with test executive tools and statistical analysis in a general approach designated ‘Accelerated Mode Test’ (AMT).
Benefits of this approach yield higher coverage of faults, including those associated with ongoing process, design and component or material behaviors, in factory and field environment, while at the same time providing minimum test times.