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.

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.

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.

Test functions (fault detection, diagnosis, error correction, repair, etc.) that are applied concurrently while the system continues its intended function are defined as on-line testing. In its expanded scope, on-line testing includes the design of concurrent error checking subsystems that can be themselves self-checking, fail-safe systems that continue to function correctly even after an error occurs, reliability monitoring, and self-test and fault-tolerant designs. On-Line Testing for VLSI contains a selected set of articles that discuss many of the modern aspects of on-line testing as faced today. The contributions are largely derived from recent IEEE International On-Line Testing Workshops. Guest editors Michael Nicolaidis, Yervant Zorian and Dhiraj Pradhan organized the articles into six chapters. In the first chapter the editors introduce a large number of approaches with an expanded bibliography in which some references date back to the sixties. On-Line Testing for VLSI is an edited volume of original research comprising invited contributions by leading researchers.