Measurement Techniques to Identify Soft Failure Sensitivity to ESD

Electrostatic discharge (ESD)-induced soft failures are a critical issue for electronic systems as the failures are mostly found after the hardware design is completed. Any changes applied to the hardware may delay the project. Diagnostic tools capable of identifying soft failure-induced malfunctions in an early stage of product design help to reduce the risk of late stage ESD-induced project delays. In many cases, soft failures can be directly observed by the user interface, system crash, or other obvious indicators. However, in an early product design stage the operation system may be marginal and applications may not be available. To improve the ability to detect soft failure critical design choices, this paper presents several methods to identify ESD-induced changes which may not be observable via direct observation. These methods include the observation of ac or dc currents, monitoring dc voltages, capturing near fields and processing them via short-term fast fourier transform (FFT), wavelet transformation, down mixing to audible range, and monitoring for latch-up via thermal imaging. The paper introduces the basis of each method, shows examples, and compares them for their detection ability.