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ESD Design and Analysis Handbook presents an overview of ESD as it effects electronic circuits and provides a concise introduction for students, engineers, circuit designers and failure analysts. This handbook is written in simple terms and is filled with practical advice and examples to illustrate the concepts presented.
While this treatment is not exhaustive, it presents many of the most important areas of the ESD problem and suggests methods for improving them. The key topics covered include the physics of the event, failure analysis, protection, characterization, and simulation techniques. The book is intended as both an introductory text on ESD and a useful reference tool to draw on as the reader gains experience. The authors have tried to balance the level of detail in the ESD Design and Analysis Handbook against the wealth of literature published on ESD every year. To that end, each chapter has a topical list of references to facilitate further in-depth study.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Physics and Models of an ESD Event

Abstract
Electrostatic discharge (ESD) events occur all around us. We might not know these events by the name ‘ESD’ but nevertheless they happen. The first time many people experienced ESD was on a cold dry winter day as a child. Going out of the house we walked across the carpet not knowing that the act of walking was charging our bodies to 1000’s of volts. Unsuspectingly, we reached for the door to open it and go outside. As our hand approached the doorknob a small spark flashed between our hand and the doorknob. The spark scared us and also hurt. The doorknob was at a lower potential than our bodies. This caused the charge to pass from our body through our hand to the doorknob. Confused we asked our parents. They probably just said, “You just shocked yourself. Go on out and play” Being more careful we opened the door but this time there was no shock because we had been discharged already. Even though we were confused we went on out and played.
James E. Vinson, Joseph C. Bernier, Gregg D. Croft, Juin J. Liou

Chapter 2. Failure Analysis Techniques

Abstract
Failure analysis is a necessary part of any semiconductor manufacturer’s operation. Failure analysis is the tool used for product and process improvement. Without failure analysis it is impossible to determine the cause of failure and implement corrective actions to prevent its reoccurrence. ESD related failures come from two primary sources. The first are failures produced by the ESD testers as a result of product classification. Part of a new product’s qualification process includes determining its ESD threshold and in turn, its ESD classification. Samples of parts are tested using the three ESD models detailed in Chapter 1. The parts that fail may require failure analysis to determine the weaknesses in the design or to learn how to improve the design. The other source of ESD related failure is product failure during manufacture or from the field. These failures may be caused by ESD or they could be caused by any number of failure mechanisms. The product failures where the source of the failure is not known require more methodical analysis so these other failure sources can be evaluated. This section will not attempt to provide an exhaustive review of failure analysis techniques but will focus on the techniques employed with failures originating from ESD testing. The general concepts reviewed here are applicable to any failure analysis but may not cover all of the steps and techniques available to locate failures that are not ESD related.
James E. Vinson, Joseph C. Bernier, Gregg D. Croft, Juin J. Liou

Chapter 3. Environmental Protection

Abstract
This chapter focuses on the generation and build up of charge and how these charges are allowed to move and interact with sensitive components. Environmental Protection implements procedures and uses extra equipment whose purpose is to limit charge build up and control the discharge path. This form of protection is one of two essential means of providing an overall ESD protection strategy. The other technique is increasing circuit robustness and is described in Chapter 4. For many years environmental protection was the major form of protection against ESD. This was due in part to the fact that building protection into circuits was more difficult and greater payback could be achieved through reducing the likelihood of an ESD event or reducing the event’s magnitude. As components became more sensitive it was clear that environmental protection alone was not capable of sustaining the level of protection necessary. The components themselves must be made more robust to ESD. A total protection strategy works to achieve the most robust device operating in the safest environment.
James E. Vinson, Joseph C. Bernier, Gregg D. Croft, Juin J. Liou

Chapter 4. Chip Level Protection

Abstract
Chapter 3 reviewed one form of protection — environmental protection. This focused on reducing the likelihood that an ESD event would occur and minimizing the magnitude of any discharge. The problem with only doing this form of protection is the fact that having an ESD event is inevitable. At some point in a part’s useful life it will be exposed to an ESD event. It is not sufficient to assume that the level of the ESD event will be low enough to allow it to continue to function. The designer must assume the responsibility for providing the most robust circuit that can be built within the constraints of the project. This brings us to the focus of this chapter — providing chip level protection. Chip level protection has two aspects that are key to its success. The first is directing the charge (current) through elements designed to carry it without being destroyed. The second is clamp the voltage produced by the conduction path below the voltage that causes damage. Conducting the current and clamping the voltage are the key points to providing ESD protection. The goal is to minimize the current density and electric field in a device during the ESD event [4–1].
James E. Vinson, Joseph C. Bernier, Gregg D. Croft, Juin J. Liou

Chapter 5. Device Characterization

Abstract
Reliable circuit design is critically dependent on the quality of the circuit models used. During the development of a new wafer fabrication process one of the first things provided to circuit designers are electrical models of the circuit elements. These device models are used in a simulator to allow the circuit designer to predict the electrical behavior and performance of the circuit prior to obtaining the finished material. Each revision of the models provides a closer match to the actual devices manufactured. The models account for process variation as well as temperature variation. Other environments specific to the targeted application may also be modeled.
James E. Vinson, Joseph C. Bernier, Gregg D. Croft, Juin J. Liou

Chapter 6. ESD Modeling

Abstract
The obvious question is, “Why do I need to model ESD?” Modeling describes a physical process in mathematical terms. The equations describing the physical processes are used to simulate its response to external stimulus. Through this mathematical simulation we can study the physical processes and understand their behavior with regard to changes in the stimulus or in the equations comprising the model. The goal in any model is to perfectly represent in a mathematical form what occurs in the physical form, but achieving this goal can be elusive. The simulation space where a model is valid is often just a subset of the total operational space. As an example, the behavior of a spring can be described as a simple linear relationship between the distance traveled and the force exerted (F=k•x; where F=force, x=distance; k=spring ratio) provided the spring is not allowed to stretch beyond its elastic limit. Figure6-1 shows the stress-strain (force-distance) curve for a spring. The elastic region is the linear portion at the beginning of the curve. In this region the spring will return to its original shape after the force is removed. Once the spring crosses over to the plastic region structural changes in the spring have occurred. The spring will not behave the same as it once did. The simplified model only covers the linear region. The equations governing the entire space up to the point where the spring fails are more complicated and difficult to model.
James E. Vinson, Joseph C. Bernier, Gregg D. Croft, Juin J. Liou

Backmatter

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