System-level transient ESD noise monitoring using off-chip and on-chip circuits

Department of Electrical EngineeringElectrostatic discharge (ESD) is defined as a sudden flow of electric charge between the objects with different electrostatic potentials caused by contact and breakdown of air gap or dielectric layer. In electronic systems, ESD is the remarkable critical issue for reliability of compact and complex integrated circuits (IC) and systems and must be deliberated from the initial design process for the safety of users and wasted cost from damaged products. To analyze the effects by the ESD events, the noise voltages inside the products induced by ESD events can be measured. However, the passive measurement method using cables has some limitations. Various on-die ESD detector circuits have previously been proposed to overcome the limits, providing the useful information for ESD noise analysis. But these circuits require lots of time and cost for design and fabrication, so it is hard to apply from the initial design process. In this thesis, two approaches are proposed for monitoring the system-level transient ESD noise as the further progress of previous researches regarding the detection of system-level transient ESD event. One is the usage of the off-chip ESD detection module including multiple detection circuits with different thresholds for characterizing the range of ESD noises. The proposed detection circuit utilizes the time delay by RC network and can sense the positive ESD events at power line. The sensing characteristics of the detection circuit against ESD event can be represented as a threshold curve. Utilizing the detection threshold curve, the range of ESD noises can be estimated without measurement. For more specific identification of ESD noise range, the detection module with multiple detection circuits are designed and the more exact estimation of noise range becomes possible, depending on which detection circuits sense the ESD event. The threshold curves of detection module are extracted using transmission line pulse (TLP) signals and validated through ESD current injection tests. After then, as an application to real situation, the system-level transient ESD noises in a commercial solid-state drive (SSD) storage system are characterized and analyzed. The other approach is the capturing the noise waveform itself like digital oscilloscope. Although the previous on-die ESD detector circuits and the proposed approach provide useful information, it is further demanded to obtain the accurate noise waveforms for more complete analysis. So, an on-die oscilloscope circuit including on-chip ESD event detectors is designed and fabricated in a 180-nm CMOS process. The validation of operation is performed, and the measurement results of on-chip ESD detectors are comparable to the results from circuit simulations. However, the ability of waveform capturing is under the designed specification due to several problems in circuit design process.clos

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