Prelidding Burn-In Evaluation.

摘要

Screening of hybrid circuits is designed to identify and eliminate early electrical failures. Rework of these failures is complicated by the fact that the hybrids are sealed. This evaluation was designed to determine whether or not it is feasible to perform part of the burn-in portion of the screening sequence prior to package sealing. A hybrid circuit was designed to incorporate a wide range of components and materials and to permit access to points internal to the circuit for parametric shift detection. A test plan was devised to assess the efficiency of performing prelid burn-in under various conditions and to verify that no long term deleterious effects were introduced. Results of this evaluation have shown that prelidding burn-in is effective and is non-destructive. It should be performed in a dry nitrogen, Class 10,000 maximum, environment at 125 deg. C for 48 hours. Sealed lid burn-in should be performed after prelidding burn-in at 125 deg. C. Total minimum burn-in time of 160 hours at 125 deg. C can be divided between prelidding and sealed lid burn-in provided that the total burn-in time equals or exceeds the specified 160 hour burn-in time equals or exceeds 96 hours.