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An evaluation of plastic coatings for high reliability microcircuits
Microelectron.Reliab..Vol.22. No. 4. pp. 895-91I. 1982. Printedin Great Britain.
0026-2714/82/040895-17503.00/0 © 1982PergamonPressLtd.
W O R L D ABSTRACTS O N M I C R O E L E C T R O N I C S A N D RELIABILITY The abstracts below are given in reasonable detail where necessary so that an appreciation can be made of the co~,erage of the article. They are probably the most comprehensive detailed abstracts published in these two fields and in general are all of articles published within the last 12 months. They are classified into the following sections. Subjects 1. Reliability--General. 2. Reliability of Components, Tubes, Transistors and ICs. 3. Circuit and Systems Reliability, Maintenance and Redundancy. 4. Microelectronics--General. 5. Microelectronics--Design and Construction. 6. Microelectronics--Components, Systems and Equipments. 7. Semiconductor Integrated Circuits, Devices and Materials. 8. Thick- and Thin-Film Components, Hybrid Circuits and Materials. 9. Electron, Ion and Laser Beams.
1. R E L I A B I L I T Y - - G E N E R A L The mission profile. ROBERT BERNARD and NICOLAS MOKHOEF. IEEE Spectrum, 47 (October 1981 ). Satisfying the "customer" entails balancing a product's reliability with availability and maintainability. 2. R E L I A B I L I T Y
OF COMPONENTS,
An evaluation of plastic coatings for high reliability microcircuits. NIHAL SINNADURAI. Microelectronics J. 12 (6), 30 (1981). A systematic evaluation of a range of plastic coatings, to identify those suitable for use on bare microcircuit dice for high reliability applications, has been conducted by materials analyses and by damp heat overstress of coated special test vehicles. Some promising junction coatings were first selected and then used in subsequent tests with added top coatings in order to evaluate a range of composite coatings. Over 4000 hours of overstress have been accumulated from tests on some 500 test vehicles and over 15 different coatings examined. The materials analyses provided a coarse screen and roughly correlated with the damp heat test results, which proved to be more discriminating. While some junction coatings gave excellent results, it was very apparent that their performance could be severely impaired by the addition of poor top coatings. Nevertheless the outcome from this exercise has been the identification of a number of promising pairs of coatings, with the caution that evaluations with more sensitive active elements have yet to be done. A note on lC-yield statistics. R. M. WARNER,JR. Solid-State Electronics 24 (11 ), 1045 (1981). Expressions given by Moore and by Dingwall for relating integrated-circuit yield to area are compared and are given a common interpretation in terms of the composite model. The issue of large-chip yield projection is discussed, a subject that is still unclear because of the concave-up projections of the empirical curves, the linear projection of the composite model, and the concavedown projections of recent analytical models. BS9000 components and reliability quality factors: suggested use of MIL-HDBK-217C factors based on a comparative product assurance analysis. J. G. GISSING, Microelectron. Reliab. 21 (5), 683 (1981). The calculation of electronic component failure rates using the MIL-HDBK-217C failure 895
Overlooking the obvious. ROBERT BERNARD.IEEE Spectrum, 85 (October 1981 ). In large, complex systems, even the most careful designer can lose sight of an obvious error.
TUBES,
TRANSISTORS
AND
ICs
rate model requires an assessment of component quality-the rcQ factor. Quality factors are not directly available for BS9000/CECC components and application of the MILHDBK-217C model becomes difficult. The paper makes a comparative analysis of the product assurance programmes of MIL-SPEC and BS/CECC components and suggests that quality factors as published in the MIL-HDBK can be assigned to UK approved components. Quality factors relevant to UK product assurance levels are tabled for all active and passive devices.in the BS9000 series. A more detailed comparison between UK passives and MIL-SPEC Established Reliability devices will require a Certified Test Record (CTR) analysis. Such an analysis is now becoming possible as CTR data is assembled on the M O D U S data bank of the University of Sheffield. Some of the problems and limitations of a CTR analysis are briefly mentioned. Reliability problems in TTL-LS devices. C. CANALI, F. FANTINI, S. GAVIRAGHI and A. SENIN. Microelectron. Reliab. 21 (5), 637 (1981). An analysis of the possible failure modes of TTL-LS was carried out, with particular emphasis on long term thermal stability of Schottky diodes, all realized by PtSi-Ti/W-AI metallization system. Only from one supplier were there diodes in which changes in the characteristics, due to metallization defects, were observed during accelerated thermal cycles. On the contrary, once its uniformity is guaranteed, the Ti/W barrier layer inhibits the Si-AI interdiffusion up to 550°C, 1 hr thermal annealing. Sensitivity to negative input pulses and electrical overstresses were also investigated. Scanning electron microscope and microprobe, and voltage contrast techniques seem to be more suitable instruments to investigate the reliability of such devices than the conventional life tests.
0026-2714/82/040895-17503.00/0 © 1982PergamonPressLtd.
W O R L D ABSTRACTS O N M I C R O E L E C T R O N I C S A N D RELIABILITY The abstracts below are given in reasonable detail where necessary so that an appreciation can be made of the co~,erage of the article. They are probably the most comprehensive detailed abstracts published in these two fields and in general are all of articles published within the last 12 months. They are classified into the following sections. Subjects 1. Reliability--General. 2. Reliability of Components, Tubes, Transistors and ICs. 3. Circuit and Systems Reliability, Maintenance and Redundancy. 4. Microelectronics--General. 5. Microelectronics--Design and Construction. 6. Microelectronics--Components, Systems and Equipments. 7. Semiconductor Integrated Circuits, Devices and Materials. 8. Thick- and Thin-Film Components, Hybrid Circuits and Materials. 9. Electron, Ion and Laser Beams.
1. R E L I A B I L I T Y - - G E N E R A L The mission profile. ROBERT BERNARD and NICOLAS MOKHOEF. IEEE Spectrum, 47 (October 1981 ). Satisfying the "customer" entails balancing a product's reliability with availability and maintainability. 2. R E L I A B I L I T Y
OF COMPONENTS,
An evaluation of plastic coatings for high reliability microcircuits. NIHAL SINNADURAI. Microelectronics J. 12 (6), 30 (1981). A systematic evaluation of a range of plastic coatings, to identify those suitable for use on bare microcircuit dice for high reliability applications, has been conducted by materials analyses and by damp heat overstress of coated special test vehicles. Some promising junction coatings were first selected and then used in subsequent tests with added top coatings in order to evaluate a range of composite coatings. Over 4000 hours of overstress have been accumulated from tests on some 500 test vehicles and over 15 different coatings examined. The materials analyses provided a coarse screen and roughly correlated with the damp heat test results, which proved to be more discriminating. While some junction coatings gave excellent results, it was very apparent that their performance could be severely impaired by the addition of poor top coatings. Nevertheless the outcome from this exercise has been the identification of a number of promising pairs of coatings, with the caution that evaluations with more sensitive active elements have yet to be done. A note on lC-yield statistics. R. M. WARNER,JR. Solid-State Electronics 24 (11 ), 1045 (1981). Expressions given by Moore and by Dingwall for relating integrated-circuit yield to area are compared and are given a common interpretation in terms of the composite model. The issue of large-chip yield projection is discussed, a subject that is still unclear because of the concave-up projections of the empirical curves, the linear projection of the composite model, and the concavedown projections of recent analytical models. BS9000 components and reliability quality factors: suggested use of MIL-HDBK-217C factors based on a comparative product assurance analysis. J. G. GISSING, Microelectron. Reliab. 21 (5), 683 (1981). The calculation of electronic component failure rates using the MIL-HDBK-217C failure 895
Overlooking the obvious. ROBERT BERNARD.IEEE Spectrum, 85 (October 1981 ). In large, complex systems, even the most careful designer can lose sight of an obvious error.
TUBES,
TRANSISTORS
AND
ICs
rate model requires an assessment of component quality-the rcQ factor. Quality factors are not directly available for BS9000/CECC components and application of the MILHDBK-217C model becomes difficult. The paper makes a comparative analysis of the product assurance programmes of MIL-SPEC and BS/CECC components and suggests that quality factors as published in the MIL-HDBK can be assigned to UK approved components. Quality factors relevant to UK product assurance levels are tabled for all active and passive devices.in the BS9000 series. A more detailed comparison between UK passives and MIL-SPEC Established Reliability devices will require a Certified Test Record (CTR) analysis. Such an analysis is now becoming possible as CTR data is assembled on the M O D U S data bank of the University of Sheffield. Some of the problems and limitations of a CTR analysis are briefly mentioned. Reliability problems in TTL-LS devices. C. CANALI, F. FANTINI, S. GAVIRAGHI and A. SENIN. Microelectron. Reliab. 21 (5), 637 (1981). An analysis of the possible failure modes of TTL-LS was carried out, with particular emphasis on long term thermal stability of Schottky diodes, all realized by PtSi-Ti/W-AI metallization system. Only from one supplier were there diodes in which changes in the characteristics, due to metallization defects, were observed during accelerated thermal cycles. On the contrary, once its uniformity is guaranteed, the Ti/W barrier layer inhibits the Si-AI interdiffusion up to 550°C, 1 hr thermal annealing. Sensitivity to negative input pulses and electrical overstresses were also investigated. Scanning electron microscope and microprobe, and voltage contrast techniques seem to be more suitable instruments to investigate the reliability of such devices than the conventional life tests.