Electrical Overstress Protection For Electronic Devices

Electrical Overstress (EOS) continues to impact semiconductor manufacturing, semiconductor components and systems as technologies scale from micro- to nano-electronics. This bookteaches the fundamentals of electrical overstress and how to minimize and mitigate EOS failures. The text provides a clear picture of EOS phenomena, EOS origins, EOS sources, EOS physics, EOS failure mechanisms, and EOS on-chip and system design. It provides an illuminating insight into the sources of EOS in manufacturing, integration of on-chip, and system level EOS protection networks, followed by examples in specific technologies, circuits, and chips. The book is unique in covering the EOS manufacturing issues from on-chip design and electronic design automation to factory-level EOS program management in today’s modern world. Look inside for extensive coverage on: Fundamentals of electrical overstress, from EOS physics, EOS time scales, safe operating area (SOA), to physical models for EOS phenomena EOS sources in today’s semiconductor manufacturing environment, and EOS program management, handling and EOS auditing processing to avoid EOS failures EOS failures in both semiconductor devices, circuits and system Discussion of how to distinguish between EOS events, and electrostatic discharge (ESD) events (e.g. such as human body model (HBM), charged device model (CDM), cable discharge events (CDM), charged board events (CBE), to system level IEC 61000-4-2 test events) EOS protection on-chip design practices and how they differ from ESD protection networks and solutions Discussion of EOS system level concerns in printed circuit boards (PCB), and manufacturing equipment Examples of EOS issues in state-of-the-art digital, analog and power technologies including CMOS, LDMOS, and BCD EOS design rule checking (DRC), LVS, and ERC electronic design automation (EDA) and how it is distinct from ESD EDA systems EOS testing and qualification techniques, and Practical off-chip ESD protection and system level solutions to provide more robust systems Electrical Overstress (EOS): Devices, Circuits and Systems is a continuation of the author’s series of books on ESD protection. It is an essential reference and a useful insight into the issues that confront modern technology as we enter the nano-electronic era.

Practical rules and strategies designed to protect electronic systems from damage by transient overvoltages include symptoms and threats, remedies, protective devices and their applications, and validation of protective measures. 1989 edition.

Electrical overstress (EOS) and Electrostatic discharge (ESD) pose one of the most dominant threats to integrated circuits (ICs). These reliability concerns are becoming more serious with the downward scaling of device feature sizes. Modeling of Electrical Overstress in Integrated Circuits presents a comprehensive analysis of EOS/ESD-related failures in I/O protection devices in integrated circuits. The design of I/O protection circuits has been done in a hit-or-miss way due to the lack of systematic analysis tools and concrete design guidelines. In general, the development of on-chip protection structures is a lengthy expensive iterative process that involves tester design, fabrication, testing and redesign. When the technology is changed, the same process has to be repeated almost entirely. This can be attributed to the lack of efficient CAD tools capable of simulating the device behavior up to the onset of failure which is a 3-D electrothermal problem. For these reasons, it is important to develop and use an adequate measure of the EOS robustness of integrated circuits in order to address the on-chip EOS protection issue. Fundamental understanding of the physical phenomena leading to device failures under ESD/EOS events is needed for the development of device models and CAD tools that can efficiently describe the device behavior up to the onset of thermal failure. Modeling of Electrical Overstress in Integrated Circuits is for VLSI designers and reliability engineers, particularly those who are working on the development of EOS/ESD analysis tools. CAD engineers working on development of circuit level and device level electrothermal simulators will also benefit from the material covered. This book will also be of interest to researchers and first and second year graduate students working in semiconductor devices and IC reliability fields.

Many of the major semiconductor manufacturers have published the results of their own in-house design evaluations of new electrostatic discharge (ESD) protection networks. Several major users have published test and evaluation results on the ESD protection networks used on a wide cross-section of popular device types available today. The present work was undertaken to expand that data base and to compare the failure mechanisms which occur in devices subjected to both the human body and the charged device ESD simulation tests. The conclusions of this report are similar to those other workers. Failure mechanisms induced with the human body model are primarily electrothermal junction shorting, often associated with aluminum/silicon contacts near the bonding pads (an interlevel polysilicon layer placed between the aluminum and silicon in such contacts significantly raises the failure threshold). Layout mistakes such as closer spacing of protective network components to other junctions can cause significantly lowered failure thresholds for a pin. Interlayer oxide shorts were found to occur in some networks. The charged device test induced failures at much lower voltages but the failure mechanisms were similar in the best protective networks. In almost every case there were easily recognized reasons for increased sensitivity on one or more pins which could be fixed by minor layout changes.

Electromagnetic pulses from nuclear weapons, lightning, and electrostatic discharge are three examples of electrical overstress. Such overstress can cause failure, permanent degradation, or temporary malfunction (upset) of electronic devices and systems. This problem and general solutions are briefly reviewed. Nonlinear components and circuits for protection from electrical overstress are discussed in detail, emphasizing spark gaps, metal oxide varistors, and avalanche diodes. However, other components, such as semiconductor diodes, thyristors, resistors, inductors, and optoisolators are also discussed. Applications of these nonlinear components are discussed in the context of signal lines, AC power lines, and DC power supplies. The final chapter discusses specific upset protection circuits.

With the evolution of semiconductor technology and global diversification of the semiconductor business, testing of semiconductor devices to systems for electrostatic discharge (ESD) and electrical overstress (EOS) has increased in importance. ESD Testing: From Components to Systems updates the reader in the new tests, test models, and techniques in the characterization of semiconductor components for ESD, EOS, and latchup. Key features: Provides understanding and knowledge of ESD models and specifications including human body model (HBM), machine model (MM), charged device model (CDM), charged board model (CBM), cable discharge events (CDE), human metal model (HMM), IEC 61000-4-2 and IEC 61000-4-5. Discusses new testing methodologies such as transmission line pulse (TLP), to very fast transmission line pulse (VF-TLP), and future methods of long pulse TLP, to ultra-fast TLP (UF-TLP). Describes both conventional testing and new testing techniques for both chip and system level evaluation. Addresses EOS testing, electromagnetic compatibility (EMC) scanning, to current reconstruction methods. Discusses latchup characterization and testing methodologies for evaluation of semiconductor technology to product testing. ESD Testing: From Components to Systems is part of the authors’ series of books on electrostatic discharge (ESD) protection; this book will be an invaluable reference for the professional semiconductor chip and system-level ESD and EOS test engineer. Semiconductor device and process development, circuit designers, quality, reliability and failure analysis engineers will also find it an essential reference. In addition, its academic treatment will appeal to both senior and graduate students with interests in semiconductor process, device physics, semiconductor testing and experimental work.