Environmental stress screening of electronic assemblies, a thermal transient study

Recent studies have strengthened the case for applying a “Load-Strength Margin“ (LSM) approach to the design of stress screening profiles. This approach emerges from the achievement of progressively increasing product design robustness before transfer to manufacture, and requires that electronic hardware response to various thermal and mechanical input functions be controlled and measured. An in-depth review of current techniques for the prediction of thermal responses of electronic assemblies to various heat input functions as a basis for designing thermal screens, has exposed a number of theoretical and practical shortfalls. This study examines methods for achieving component and material energy transfer consistent with thermal screening requirements, and describes essential measurement techniques. Results and conclusions are provided, together with recommendations for improvement in thermal cycling chamber design and operational features