From Halt and Hasa to Interconnect Reliability

ABSTRACT To reveal the design weakness and material latent defect of electronic product, conventional Highly Accelerated Life Testing (HALT) is widely used in the Design Verification Test (DVT) stage. A relative new approach, Highly Accelerated Stress Audit (HASA) is also used in mass production stage to screen the product quality before the shipment. Although the stress level of these test are significant difference in term of their correlation to the interconnect reliability and life time. In this article, HALT is used on an emulated electronic test vehicle in development stage to uncover latent defect in design, component selection and manufacturing that would not otherwise be found through regular qualification. During the assessment, failure mode and operation limit are carefully reviewed to benchmark for the setting of HASA. Failure modes in the overall view as well as in the microstructure level are studied to help the understanding of the distinction to the fatigue failure mechanism. The life of package-Lead Free Solder-PCB interconnect system is studied by accelerated thermal cycling to correlate the residual stress from HASA to the reliability scale. Field data of the product will be reviewed on the case of test vehicle without HASA and with HASA. Distribution model of the field data will be correlated to the ALT data to evaluate the variation of shape parameter and Eta life. In the product development stage the HALT will facilitate the understanding the weakest link in the material characteristic. On the ongoing basis, the correlation between HASA to life will help the quality screening process.