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Procedures for selection of semiconductor diodes for use in undersea cable systems
WORLD
ABSTRACTS
ON MICROELECTRONICS
AND
RELIABILITY
203
enough known as to not require any further elaboration. There are, however, certain aspects of the technologies utilized in making the contact between a conductor layer and the plated-thru-hole which are poorly understood, and in most cases, not controlled in production. This results in a variation of physical properties of the interconnection and reliability of that point. When we consider an interconnecting network, or a multilayer board consisting of nine layers and 36,000 holes, then the probability of a failure, due to at least one contact being defective, is staggering. For some time we have been studying the failure mode of the electrical contact in multilayer boards and have found a number of rather obvious conditions that lead to failures. There are some that are less obvious, that will be explored in the following discussion.
the production process. Because no advance knowledge exists as to which are the substandard components, their presence affects the reliability. A great part of the substandard components can be eliminated by means of debugging procedures, but due to a nonzero proportion of defectives of the component population, it is impossible to eliminate all of the sub-standard components through conventional debugging processes. To remedy this drawback, this paper presents a new debugging process that is capable of eliminating almost all of the substandard components. From an analysis and comparison of the new debugging process with the conventional method, it has become evident that we can reduce the fraction defective of the lot after debugging by several orders of magnitude when compared with the conventional method.
P r o c e d u r e s for s e l e c t i o n o f s e m i c o n d u c t o r d i o d e s for u s e in u n d e r s e a c a b l e s y s t e m s . I. G. ABRAHAMsoN, E. T. LEE and E. B. SLUTSKY.IEEE Tram. Reliab. R-21, No. 4, November (1972), p. 200. The non-redundant transistorized repeaters used in undersea cable systems are intended to operate on the ocean floor without maintenance for 20 yr. T o provide the best possible assurance that this high level of reliability is in fact attained, semiconductor transistors and diodes manufactured for cable use are screened to identify and eliminate the early failures. Devices surviving the screening are then subjected, for at least 6 months, to real time aging which simulates the worst-case useconditions. The devices are removed from the aging environment and certain of the devices are selected for use in undersea cable operation. It is the purpose of this paper to discuss the empirically derived procedures for selecting two types of semiconductor diodes. T h e test data on which the selection is based consist, in each case, of period measurements of four electrical parameters while the diodes are aging. There was apparently no accepted and well formulated statistical model for the data on which a conventional technique could be based. Thus more unconventional procedures for device selection had to be constructed. The selection procedures have been implemented and perform well.
A l o o k at r e l i a b i l i t y : t u b e s a n d s o l i d state. J. W. RUSH and D. M. COLE. Microwave J., October (1972), p. 17. Most new microwave systems are designed using as many solid-state components as practical. Many older systems are still being used for reasons of high replacement cost. The newer systems in most cases perform additional functions. T h e old system requires significant maintenance but the long-term cost of operation must be considered. All of these concerns are affected by the reliability of the old and new and in many cases by the question, "Is the solid state approach to microwave systems really more reliable?". This article makes no claim to authoritative documentation of tubes vs solid state---which is more reliable? This is not possible for several reasons : (1) the basic devices require a different environment for optimum performance; (2) there have not been equal efforts to improve the reliability of both devices; (3) very few examples exist where the devices are competing on a one-for-one basis.
Microstructure and reliability of ceramic chip c a p a c i t o r s . J. PIPER. Proceedings I S H M Microelectronics Symposium, October-November (1972), p. 4-A2-1. A survey of failure and performance degradation modes of ceramic chips shows a wide range of mechanisms most of which are not intrinsic to the basicmaterials and construction of this component. Because the lack of a general, predominant failure mode limits the success of normal test and " b u r n - i n " techniques in guaranteeing reliability, control of materials and manufacturing operations becomes vital. M u l t i l a y e r d e b u g g i n g p r o c e s s (a n e w m e t h o d o f s c r e e n i n g ) . T. NINOMIYAand K. HARADA.IEEE Tram. Reliab. R-21, No. 4, November (1972), p. 224. In general, a small proportion of components will be substandard because of some imperfection in the control of
I n f l u e n c e o f t h e p r o t e c t i v e g a s p r e s s u r e on s h o w e r i n g i n d r y r e e d c o n t a c t s . D. SCHUOCKER and M. SCHMITT. IEEE Tram. Parts, Hybrids Packng PHP-8, No. 4, December (1972), p. 58. We investigated the effect of a reduction of the protective gas pressure at fixed static breakdown voltage on the appearance of showering (intermittent arcing) in dry reed contacts that break inductive circuits by using a discharge gap and an auxiliary interruptor to simulate this condition. We found a critical pressure range, where showering, capable of causing strong erosion, is replaced by glow discharges. In the case of actually operating contacts, it was only possible to reduce showering for 40 per cent of the total openings by lowering the gas pressure. These results can be explained by suggesting that in the case of the discharge gap that represents a relay opening contact having large contact spacing, the showering arcs, developed from the preceding glow discharges, can be minimized by reducing the gas pressure in such a way that arc formation is inhibited. In the case of the operating contact, other mechanisms exist, such as high electrical fields and high temperature spots. These mechanisms are not affected much by reducing the gas pressure; thus showering is only partially prevented.
ABSTRACTS
ON MICROELECTRONICS
AND
RELIABILITY
203
enough known as to not require any further elaboration. There are, however, certain aspects of the technologies utilized in making the contact between a conductor layer and the plated-thru-hole which are poorly understood, and in most cases, not controlled in production. This results in a variation of physical properties of the interconnection and reliability of that point. When we consider an interconnecting network, or a multilayer board consisting of nine layers and 36,000 holes, then the probability of a failure, due to at least one contact being defective, is staggering. For some time we have been studying the failure mode of the electrical contact in multilayer boards and have found a number of rather obvious conditions that lead to failures. There are some that are less obvious, that will be explored in the following discussion.
the production process. Because no advance knowledge exists as to which are the substandard components, their presence affects the reliability. A great part of the substandard components can be eliminated by means of debugging procedures, but due to a nonzero proportion of defectives of the component population, it is impossible to eliminate all of the sub-standard components through conventional debugging processes. To remedy this drawback, this paper presents a new debugging process that is capable of eliminating almost all of the substandard components. From an analysis and comparison of the new debugging process with the conventional method, it has become evident that we can reduce the fraction defective of the lot after debugging by several orders of magnitude when compared with the conventional method.
P r o c e d u r e s for s e l e c t i o n o f s e m i c o n d u c t o r d i o d e s for u s e in u n d e r s e a c a b l e s y s t e m s . I. G. ABRAHAMsoN, E. T. LEE and E. B. SLUTSKY.IEEE Tram. Reliab. R-21, No. 4, November (1972), p. 200. The non-redundant transistorized repeaters used in undersea cable systems are intended to operate on the ocean floor without maintenance for 20 yr. T o provide the best possible assurance that this high level of reliability is in fact attained, semiconductor transistors and diodes manufactured for cable use are screened to identify and eliminate the early failures. Devices surviving the screening are then subjected, for at least 6 months, to real time aging which simulates the worst-case useconditions. The devices are removed from the aging environment and certain of the devices are selected for use in undersea cable operation. It is the purpose of this paper to discuss the empirically derived procedures for selecting two types of semiconductor diodes. T h e test data on which the selection is based consist, in each case, of period measurements of four electrical parameters while the diodes are aging. There was apparently no accepted and well formulated statistical model for the data on which a conventional technique could be based. Thus more unconventional procedures for device selection had to be constructed. The selection procedures have been implemented and perform well.
A l o o k at r e l i a b i l i t y : t u b e s a n d s o l i d state. J. W. RUSH and D. M. COLE. Microwave J., October (1972), p. 17. Most new microwave systems are designed using as many solid-state components as practical. Many older systems are still being used for reasons of high replacement cost. The newer systems in most cases perform additional functions. T h e old system requires significant maintenance but the long-term cost of operation must be considered. All of these concerns are affected by the reliability of the old and new and in many cases by the question, "Is the solid state approach to microwave systems really more reliable?". This article makes no claim to authoritative documentation of tubes vs solid state---which is more reliable? This is not possible for several reasons : (1) the basic devices require a different environment for optimum performance; (2) there have not been equal efforts to improve the reliability of both devices; (3) very few examples exist where the devices are competing on a one-for-one basis.
Microstructure and reliability of ceramic chip c a p a c i t o r s . J. PIPER. Proceedings I S H M Microelectronics Symposium, October-November (1972), p. 4-A2-1. A survey of failure and performance degradation modes of ceramic chips shows a wide range of mechanisms most of which are not intrinsic to the basicmaterials and construction of this component. Because the lack of a general, predominant failure mode limits the success of normal test and " b u r n - i n " techniques in guaranteeing reliability, control of materials and manufacturing operations becomes vital. M u l t i l a y e r d e b u g g i n g p r o c e s s (a n e w m e t h o d o f s c r e e n i n g ) . T. NINOMIYAand K. HARADA.IEEE Tram. Reliab. R-21, No. 4, November (1972), p. 224. In general, a small proportion of components will be substandard because of some imperfection in the control of
I n f l u e n c e o f t h e p r o t e c t i v e g a s p r e s s u r e on s h o w e r i n g i n d r y r e e d c o n t a c t s . D. SCHUOCKER and M. SCHMITT. IEEE Tram. Parts, Hybrids Packng PHP-8, No. 4, December (1972), p. 58. We investigated the effect of a reduction of the protective gas pressure at fixed static breakdown voltage on the appearance of showering (intermittent arcing) in dry reed contacts that break inductive circuits by using a discharge gap and an auxiliary interruptor to simulate this condition. We found a critical pressure range, where showering, capable of causing strong erosion, is replaced by glow discharges. In the case of actually operating contacts, it was only possible to reduce showering for 40 per cent of the total openings by lowering the gas pressure. These results can be explained by suggesting that in the case of the discharge gap that represents a relay opening contact having large contact spacing, the showering arcs, developed from the preceding glow discharges, can be minimized by reducing the gas pressure in such a way that arc formation is inhibited. In the case of the operating contact, other mechanisms exist, such as high electrical fields and high temperature spots. These mechanisms are not affected much by reducing the gas pressure; thus showering is only partially prevented.