ESD Protection Structure Qualification – A New Approach For System Level Reliability In Automotive Power Applications

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. These devices are protecting semiconductor products against damages due to electrostatic discharges. 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 [1-3]. The paper introduces a new 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 poststress. The experimental results are presented. For ESD protection devices release targets for automotive power applications are defined. Due to the device ageing possible impacts for the final system level ESD robustness are concluded.