Human Body Model ESD Testing

Introduction

The most common system-level method for electrostatic discharge (ESD) testing is what is sometimes referred to as the Hand Metal Model (HMM). This ESD testing method is performed per familiar standards such as IEC 61000-4-2, DO-160, MIL-STD-461 CS118, etc. We’ve previously covered other important points about the HMM method of ESD testing under the Product Insight’s category of In Compliance Magazine (See References 1 through 4 for details).

To provide further in-depth coverage of ESD testing methods, in this article, we look at another type of ESD testing based on the “Human Body Model” (HBM) method of ESD testing.

The HBM method exists because ESD is a common cause of micro-electronic circuit failures where HMM testing is lacking (HBM is performed at the micro-level whereas HMM is performed at the system-level).

It is well-known that many micro-electronic devices can be damaged or destroyed by an ESD event as low as 20 V or lower. However, what might not be so well-known is that over the past several years, sensitivity to ESD has become more evident through the use, testing, and failure analysis of these same semi-conductor/micro-devices. Additionally, the trend in technology is towards greater complexity and increased package density, which means thinner dielectrics between active elements, resulting in newer, state-of-the-art micro-electronic devices becoming even more sensitive to ESD events. For these reasons, their customers require many integrated circuit component producers to test their device’s ESD susceptibility per the HBM test method.

Common HBM ESD Test Standards

At the time of this writing, the most common HBM ESD test standards are MIL-STD-883 and JEDEC JS-001 (formerly JESD22A-114 and ANSI/ESD STM5.1-2007). The formal version of the standard is titled “ANSI/ESDA/JEDEC JS-001 Human Body Model Testing of Integrated Circuits.”

The joint ESDA/JEDEC HBM Standard JS-001-2010 merged the JEDEC HBM Standard, JESD22-A114F, and the ESDA HBM Standard, ANSI/ESD STM5.1-2007, into a single document.

ESDA/JEDEC Joint Technical Report JTR001-01-12 explains how to use the merged document to apply HBM tests to IC components.

Table 1: HBM vs HMM ESD Waveform Characteristics

HBM ESD Simulators

Caution is the order of the day when selecting an ESD Simulator for properly conducting HBM ESD testing. Just because the simulator is known to be adequate for the typical HMM testing while using the 330 Ω/150 pF high-voltage (HV) coupling network does not mean it will also be suitable for use performing HBM testing just by fitting it with the HBM 1500 Ω/100 pF HV coupling network. The waveform obtained by the latter ESD simulator may not be compliant with JS-001, i.e., it does not output the correct HBM waveform characteristics (peak current and rise time) when verified. Additionally, adjustment of the coupling network is likely impossible with these ESD simulators. If the incorrect HBM simulator is chosen, over-testing the IC component is likely to occur.

The author believes only a couple ESD simulator solutions are available that fully meet JS-001 waveform characteristics. If looking to purchase an HBM ESD simulator, the best thing to do is thoroughly research potential suppliers, ensuring they can provide waveform captures showing compliance with JS-001. These suppliers would be able to make assurances that the ESD simulator they manufacture is suitable for HBM testing. In addition, sending an ESD simulator out to an accredited, third-party test facility, with the capability to check the tester’s output waveform before purchasing, is a viable option.

References and Further Reading

1. In Compliance Magazine, February 2018, What Every Electronics Engineer Needs to Know About: ESD Simulators.
2. In Compliance Magazine, February 2019,  Let’s Talk About Design for ESD Immunity.
3. In Compliance Magazine, February 2020, The Importance of Checking the Calibration of ESD Simulators.
4. In Compliance Magazine, February 2021, A Non-Typical Use for An ESD Simulator.
5. Overview of Equipment for Human Body Model ESD Testing, ESD Guns.