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A modified bathtub curve with latent failures
534
World abstracts on microelectronics and reliability
A modified bathtub curve with latent failures. JOHN R. ENGLISH, LI YAN and THOMAS L. LANDERS.
Proceedings of the Annual IEEE Reliability and Maintainability Symposium, 217 (1995). Burn-in and stress screening are becoming increasingly popular in the commercial electronics industry as customers become increasingly sensitive to failures occurring in the useful life of a product or system. For example, thermal stress screening (TSS) is an assembly-level electronics manufacturing process that evolved from the burn-in processes used in NASA and DoD programs. While burn-in subjects the product to expected field extremes to expose infant mortalities (patent failures), TSS briefly exposes a product to fast temperature rate-of-change and out-of-spec temperatures to trigger failures that would otherwise occur during the useful life of the product. In support of this known failure behavior, the classical bathtub curve should be modified to aid in the economic modeling of various screen types. We have conducted extensive modeling efforts that have resulted in a systematic approach to explicitly modeling the latent failures in the bathtub curve. In this paper, we describe the efforts that have been dedicated to model the latent failures known to exist in many products and systems. The resulting failure distribution is a truncated, mixed Weibull distribution. This model is proving to be an effective and relatively simple means to model the complex nature of failures of a system. With this increased flexibility, we can measure the impact of stress screens in varying conditions and ultimately design optimal screens.
2. RELIABILITY O F C O M P O N E N T S , TUBES, TRANSISTORS AND ICs
Open repair technologies for MCM-D. THOMAS A. WASSICK and LAERTIS ECONOMIKOS. IEEE
Transactions on Components, Packaging, and Manufacturing Technology, Part B, 18(1), 154 (February 1995). IBM has developed various technologies for repairing defects in thin film circuitry, primarily for Multichip Module (MCM) applications. This paper discusses five technologies: laser chemical vapor depositions (LCVD), wire bond, laser-sonic bonding, solder repair, and self-induced repair, with focus on the process parameters and tooling aspects of the three established in IBM's production environment.
Reliability issues of replacing solder with conductive adhesives in power modules. OUTI RUSANEN and JAAKO KENKKERI. IEEE Transactions on Components, Packaging, and Manufacturing Technology, Part B, 18(2), 320 (May 1995). Electrically conductive adhesives are potential candidates as die attach materials for power modules because they offer simplified and environmentally compatible processing and easier reworkability compared to solder joining. There are, however, reliability issues which must be
considered carefully before the adhesives can be used in a production setting. In this study, three silver-filled epoxy-based adhesives and a solder alloy were tested in a power module test structure. The test modules went through thermal and operational cycling as well as elevated humidity and temperature aging. Mechanical stresses were endured well by most of the test adhesives. Elevated humidity and temperature aging showed, though, that the right adhesive choice is important for successful module performance. One of the adhesives was clearly superior when compared with the other two adhesives. None of them, however, showed any silver migration in the humid conditions.
Reliability comparisons for plastic-encapsulated microcircuits. BRETT BAKER and STEVE MARTIN. IEEE Transactions on Reliability, 44(1), 6 (March 1995). This paper briefly compares reliability test data obtained from plastic encapsulated microcircuits (PEM) purchased from various manufacturers. Tests include biased humidity, temperature cycling, autoclave and life tests. The results indicate differences in reliability associated with PEM from the various manufacturers. These data highlight the need for a thorough understanding of supplier quality and reliability. Consideration of component failure mechanisms in the reliability assessment of electronic equipment-Addressing the constant failure rate assumption. DAVID E. MORTIN, JANE G. K R O L E W S K I and MICHAEL J. CUSHING. Proceedings of the Annual IEEE Reliability and Maintainability Symposium, 54 (1995). The assumption of the constant failure rate can lead to excessive costs and non-optimum design decisions. As this paper shows, simply summing constant failure rates can produce results which are highly inaccurate. Highly inaccurate results can introduce significant error in decisions made for everything from product design to logistics support requirements such as spares and maintainers. If we shift from reliability accounting tasks to reliability engineering analysis, the ability to address hazard rates vs time based on root-cause failure mechanisms will become cost-effective and can become an integral part of the concurrent engineering approach to product development. The notion of the constant failure rate should no longer be accepted as a rule. Instead, statistical distributions and assumptions must be shown to be appropriate every time they are used. Simplicity alone is not a sufficient reason to use any given methodology or approach. An investigation of solder joint fatigue using electrical resistance spectroscopy. JAMES H. CONSTABLE and CHRISTINE LIZZUL. IEEE Transactions on Components, Packaging, and Manufacturing Technology, Part A, 18(1), 142 (March 1995). Interconnect electrical resistance is examined as a possible basis for a reliability tool. Measurements are reported of
World abstracts on microelectronics and reliability
A modified bathtub curve with latent failures. JOHN R. ENGLISH, LI YAN and THOMAS L. LANDERS.
Proceedings of the Annual IEEE Reliability and Maintainability Symposium, 217 (1995). Burn-in and stress screening are becoming increasingly popular in the commercial electronics industry as customers become increasingly sensitive to failures occurring in the useful life of a product or system. For example, thermal stress screening (TSS) is an assembly-level electronics manufacturing process that evolved from the burn-in processes used in NASA and DoD programs. While burn-in subjects the product to expected field extremes to expose infant mortalities (patent failures), TSS briefly exposes a product to fast temperature rate-of-change and out-of-spec temperatures to trigger failures that would otherwise occur during the useful life of the product. In support of this known failure behavior, the classical bathtub curve should be modified to aid in the economic modeling of various screen types. We have conducted extensive modeling efforts that have resulted in a systematic approach to explicitly modeling the latent failures in the bathtub curve. In this paper, we describe the efforts that have been dedicated to model the latent failures known to exist in many products and systems. The resulting failure distribution is a truncated, mixed Weibull distribution. This model is proving to be an effective and relatively simple means to model the complex nature of failures of a system. With this increased flexibility, we can measure the impact of stress screens in varying conditions and ultimately design optimal screens.
2. RELIABILITY O F C O M P O N E N T S , TUBES, TRANSISTORS AND ICs
Open repair technologies for MCM-D. THOMAS A. WASSICK and LAERTIS ECONOMIKOS. IEEE
Transactions on Components, Packaging, and Manufacturing Technology, Part B, 18(1), 154 (February 1995). IBM has developed various technologies for repairing defects in thin film circuitry, primarily for Multichip Module (MCM) applications. This paper discusses five technologies: laser chemical vapor depositions (LCVD), wire bond, laser-sonic bonding, solder repair, and self-induced repair, with focus on the process parameters and tooling aspects of the three established in IBM's production environment.
Reliability issues of replacing solder with conductive adhesives in power modules. OUTI RUSANEN and JAAKO KENKKERI. IEEE Transactions on Components, Packaging, and Manufacturing Technology, Part B, 18(2), 320 (May 1995). Electrically conductive adhesives are potential candidates as die attach materials for power modules because they offer simplified and environmentally compatible processing and easier reworkability compared to solder joining. There are, however, reliability issues which must be
considered carefully before the adhesives can be used in a production setting. In this study, three silver-filled epoxy-based adhesives and a solder alloy were tested in a power module test structure. The test modules went through thermal and operational cycling as well as elevated humidity and temperature aging. Mechanical stresses were endured well by most of the test adhesives. Elevated humidity and temperature aging showed, though, that the right adhesive choice is important for successful module performance. One of the adhesives was clearly superior when compared with the other two adhesives. None of them, however, showed any silver migration in the humid conditions.
Reliability comparisons for plastic-encapsulated microcircuits. BRETT BAKER and STEVE MARTIN. IEEE Transactions on Reliability, 44(1), 6 (March 1995). This paper briefly compares reliability test data obtained from plastic encapsulated microcircuits (PEM) purchased from various manufacturers. Tests include biased humidity, temperature cycling, autoclave and life tests. The results indicate differences in reliability associated with PEM from the various manufacturers. These data highlight the need for a thorough understanding of supplier quality and reliability. Consideration of component failure mechanisms in the reliability assessment of electronic equipment-Addressing the constant failure rate assumption. DAVID E. MORTIN, JANE G. K R O L E W S K I and MICHAEL J. CUSHING. Proceedings of the Annual IEEE Reliability and Maintainability Symposium, 54 (1995). The assumption of the constant failure rate can lead to excessive costs and non-optimum design decisions. As this paper shows, simply summing constant failure rates can produce results which are highly inaccurate. Highly inaccurate results can introduce significant error in decisions made for everything from product design to logistics support requirements such as spares and maintainers. If we shift from reliability accounting tasks to reliability engineering analysis, the ability to address hazard rates vs time based on root-cause failure mechanisms will become cost-effective and can become an integral part of the concurrent engineering approach to product development. The notion of the constant failure rate should no longer be accepted as a rule. Instead, statistical distributions and assumptions must be shown to be appropriate every time they are used. Simplicity alone is not a sufficient reason to use any given methodology or approach. An investigation of solder joint fatigue using electrical resistance spectroscopy. JAMES H. CONSTABLE and CHRISTINE LIZZUL. IEEE Transactions on Components, Packaging, and Manufacturing Technology, Part A, 18(1), 142 (March 1995). Interconnect electrical resistance is examined as a possible basis for a reliability tool. Measurements are reported of