Testing techniques for VLSI circuits are undergoing many exciting changes. The predominant method for testing digital circuits consists of applying a set of input stimuli to the IC and monitoring the logic levels at primary outputs. If, for one or more inputs, there is a discrepancy between the observed output and the expected output then the IC is declared to be defective. A new approach to testing digital circuits, which has come to be known as IDDQ testing, has been actively researched for the last fifteen years. In IDDQ testing, the steady state supply current, rather than the logic levels at the primary outputs, is monitored. Years of research suggests that IDDQ testing can significantly improve the quality and reliability of fabricated circuits. This has prompted many semiconductor manufacturers to adopt this testing technique, among them Philips Semiconductors, Ford Microelectronics, Intel, Texas Instruments, LSI Logic, Hewlett-Packard, SUN microsystems, Alcatel, and SGS Thomson. This increase in the use of IDDQ testing should be of interest to three groups of individuals associated with the IC business: Product Managers and Test Engineers, CAD Tool Vendors and Circuit Designers. Introduction to IDDQ Testing is designed to educate this community. The authors have summarized in one volume the main findings of more than fifteen years of research in this area.

Power supply current monitoring to detect CMOS IC defects during production testing quietly laid down its roots in the mid-1970s. Both Sandia Labs and RCA in the United States and Philips Labs in the Netherlands practiced this procedure on their CMOS ICs. At that time, this practice stemmed simply from an intuitive sense that CMOS ICs showing abnormal quiescent power supply current (IDDQ) contained defects. Later, this intuition was supported by data and analysis in the 1980s by Levi (RACD, Malaiya and Su (SUNY-Binghamton), Soden and Hawkins (Sandia Labs and the University of New Mexico), Jacomino and co-workers (Laboratoire d'Automatique de Grenoble), and Maly and co-workers (Carnegie Mellon University). Interest in IDDQ testing has advanced beyond the data reported in the 1980s and is now focused on applications and evaluations involving larger volumes of ICs that improve quality beyond what can be achieved by previous conventional means. In the conventional style of testing one attempts to propagate the logic states of the suspended nodes to primary outputs. This is done for all or most nodes of the circuit. For sequential circuits, in particular, the complexity of finding suitable tests is very high. In comparison, the IDDQ test does not observe the logic states, but measures the integrated current that leaks through all gates. In other words, it is like measuring a patient's temperature to determine the state of health. Despite perceived advantages, during the years that followed its initial announcements, skepticism about the practicality of IDDQ testing prevailed. The idea, however, provided a great opportunity to researchers. New results on test generation, fault simulation, design for testability, built-in self-test, and diagnosis for this style of testing have since been reported. After a decade of research, we are definitely closer to practice.

This book discusses in detail the correlation between physical defects and logic faults, and shows you how Iddq testing locates these defects. The book provides planning guidelines and optimization methods and is illustrated with numerous examples ranging from simple circuits to extensive case studies.

The 2nd edition of defect oriented testing has been extensively updated. New chapters on Functional, Parametric Defect Models and Inductive fault Analysis and Yield Engineering have been added to provide a link between defect sources and yield. The chapter on RAM testing has been updated with focus on parametric and SRAM stability testing. Similarly, newer material has been incorporated in digital fault modeling and analog testing chapters. The strength of Defect Oriented Testing for nano-Metric CMOS VLSIs lies in its industrial relevance.

The modern electronic testing has a forty year history. Test professionals hold some fairly large conferences and numerous workshops, have a journal, and there are over one hundred books on testing. Still, a full course on testing is offered only at a few universities, mostly by professors who have a research interest in this area. Apparently, most professors would not have taken a course on electronic testing when they were students. Other than the computer engineering curriculum being too crowded, the major reason cited for the absence of a course on electronic testing is the lack of a suitable textbook. For VLSI the foundation was provided by semiconductor device techn- ogy, circuit design, and electronic testing. In a computer engineering curriculum, therefore, it is necessary that foundations should be taught before applications. The field of VLSI has expanded to systems-on-a-chip, which include digital, memory, and mixed-signalsubsystems. To our knowledge this is the first textbook to cover all three types of electronic circuits. We have written this textbook for an undergraduate “foundations” course on electronic testing. Obviously, it is too voluminous for a one-semester course and a teacher will have to select from the topics. We did not restrict such freedom because the selection may depend upon the individual expertise and interests. Besides, there is merit in having a larger book that will retain its usefulness for the owner even after the completion of the course. With equal tenacity, we address the needs of three other groups of readers.