Analysis of ESD protection structure behaviour after ageing as new approach for system level reliability of automotive power devices

摘要

ESD (electrostatic discharge) protection devices as part of the device pad circuitry of semiconductors are designed for a specific wafer technology and ESD withstanding voltage. After successful qualification they will be released for a usage in high volume products where they must ensure the ESD robustness over the complete product lifetime. All present automotive qualification standards e.g. AEC (automotive electronic council) or JEDEC do not cover the assessment of the typical drifts of the characteristic electrical ESD protection device parameters after application of device specific reliability stress tests under consideration of the target ESD stress [Automotive Electronic Council, AEC-Q100-Rev-F, 2003; Automotive Electronic Council, AEC-Q101-Rev-C, 2005; JEDEC JP-001, Foundry Process Qualification Guideline, 2002]. The paper introduces a methodology to characterize ESD protection diodes after ageing by BTS (bias temperature stress) reliability tests. The used devices are partly ESD pre-stressed before application of the reliability test. The influence of the reliability stress on the ESD robustness is evaluated by using an ESD post-stress. The experimental results are presented and discussed. For ESD protection devices release targets for automotive power applications are defined.