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Bias influence on corrosion of plastic encapsulated device metal systems
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World Abstracts on Microelectronics and Reliability
Reliabilit) of thin fihn conductors and air gap crossovers
Prevention of bridging failure in mercury switches. JAMES
for hybrid circuits: tests, results and design criteria. G. F. F'IACI N IINI and G. M INLLLI. :~licroeh'clron. Reliab. 15, 451 [1976). The paper presents the results of a long study on the reliabilit\ of thin fihn conductors and cross-overs metallization for hybrid circuits. Three failure mechanisms are examined: clectromi{tration, humidily corrosion and mechanicallatique, which affi2ct the complex hybrid circuits as a consequence of the current h)ad. of the humidity and the electrical load and of the mechanical stresses induced by the encapsulant, For the humidity corrosion a new general quantitative formulation is proposed which relates temperature, poktrization and R.H. with medium time to fail. The agreement between the proposed tormulution and the results is verified both on unencapsulated and on encapsulated components and give an activation energy for NiCr Au or TiPdAu materials of q) 0.53 eV. Finally same cautelative design rules are proposed in order to have an acceptable reliability level from the design.
E. BENNETT, MICHAEL P. VAN DER WIELI'N, WALTER E, ASBELL and M. ROBERT PINt-;EL. lEE Trans. Parts, Hyhrids, Packa,qm,q PHP-12 (4), 380 (December 1976). Service failures of sealed mercury switches in relays may occur by "sticking" or by "'bridging." Analyses by scanning-electronmicroscope microprobe and by X-ray diffraction revealed that bridging fuilures in certain make-before-break-type switches can be due to the accumulation of particles of NiHg,, in the mercury which, because of increased viscosity, may form a quasi-steady bridge between the movable and fixed contacts. Doping of the mercury with copper and tin was proposed as a solution to the bridging problem based on the analysis of fulled switches and the knowledge gained from previous studies of liquid-mercury/solid-metal interactions. The results of an accelerated laboratory test and a field trial comparing the electrical characteristics o1 undupcd and doped switches confirm that the failure inechanism is thermally activated. The undoped switches were prone to bridging failure. Prevention of bridging failure in doped switches is attributed to the preferential formation of a tin-bearing layer which inhibits the dissolution of nickel and the subsequent formation of a viscous slurry of NiHg,,
Current gain degradation induced by emitter base avalanche breakdown in silicon planar transistors. A. J. MEHA. Microelectron. Reliah. 15, 619 (1976). The operation of silicon planar transistors under emitter base avalanche breakdown conditions can cause drastic reductions in current gain. Having investigated the dependence of the degradation rates on avalanche current for two types of n /->n transistor, the mechanism, carrier injection into the protective oxide is explained, and experimental data from tests on 300 transistors is compared with published theory.
Rubidium lamp stability and reliability for rubidium frequency standard. HITOSItl OYAMAI)A, KEIICHI TAKAHAStn, YOSItlKATSt SATO and H1SASHI UCIIIDA. NEC Res. Det~. 43, p. 69 (October 1976). Reliability. as well as frequency stability has come to be an important factor required for a rubidium gas cell frequency standard. Research has been conducted to determine what factors actually govern the reliability and frequency stability for a rubidium frequency standard. The research shows that the most important factor is the rubidium lamp performance, which is evaluated by the stability and profile of the radiant spectrum and by the light mteusily stability. These factors depend on lamp working conditions, such as exciting power and operating temperature as well as the manufacturing conditions. Therefore, to guarantee rubidium lamp quality, it is important to evaluate all these factors. The research shows that a change in light intensity is linear against a logarithmic time scale, and that its slope depends on exciting power and operating temperature. Research has been carried out to clarifs, the relation between life and exciting power. It also shows that life is in proportion to the minus 2nd to 3rd power of exciting power. In an attelnpt to determine the rubidium lamp failure rate, a continuous operation test has also been carried out. To date, there have been no failures, Therefore, its failure rate is less than 500 FITs and the realization of a highly reliable rubidmm lamp has become possible.
Stability and reliability of indium arsenide Hall Effect devices. R. MAN1EWSKI. Electron Technol. 9 (1), 45 (1976). A probabilistic description is given of a fixed set of technical parameters of the InAs (HA type) Hall effect devices made by lnstimte of Electron Technology. Both the parameters given and those not determined by producer but important for H E D applications, were studied. The results on ED stability were discussed and H E D reliability in respect to their parametric and catastrophic failures was estimated. Based on the obtained results it was possible to introduce somc changes in Polish H E D technology and to improve their quality.
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Bias influence on corrosion of plastic encapsulated device metal systems. BERNARD RIilCH. IEEE Trans. Reliah. R-25 (5), 296 (December 1976). Because of apparent anomalies noted on data recorded in tests conducted on P E D s (plastic encapsulated device) a re-examination of the influence of voltage biasing in temperature-humidity-bias testing has been conducted. Applied bias can have an important inIluencc on the reliability of plastic encapsulated transistors, depending on how it is applied. The analysis presented in this paper on the role of bias influence on PED failure rate explains some of the discrepancies that have been noted in the past by the author and other investigators.
Nondestructive SEM studies of Iocalised defects in gate dielectric films of MIS devices. O. K. GRWFITH. M. M. E. BEGUWALA and R. E. JOHN~)N. Proc. IEEE Reliab. Phys. p, 275 (April 1976). A nondestructive technique to identif~ localized defects in the gate dielectric of M O S devices has been developed. The technique is based upon electron beam induced conductivity modulation which gives rise to a relatively large increase in gate current under an applied bias when the beam scans a localized defect area. Measurements on devices with low gate breakdown voltage have been made and correlated with regions where subsequent catastrophic gate breakdown occurred. A circuit description and physical model of the technique is presented.
An improved approach to locating pinhole defects in MO S and bipolar integrated circuits using liquid crystals. CARMINt~ J. SALVO. Proc. IEEE Reliah. Phys. p. 263 (April 1976). Routine failure analysis of dielectric defects using nematic liquid crystals is possible with the method described in this paper. The refinements on previously described implementations result in excellent definition of the pinhole site. The paper discusses the principle involved in liquid crystal pinhole detection and details a practical liquid crystal fixture and device preparation. The influence of cell voltage polarity is illustrated and shown to be an important factor in achieving satisfactory results. The effectiveness of using dark field illumination and polarized light is shown and compared with the conventional bright field illumination used by prior authors. CMOS, M O S capacitor, and bipolar device analyses arc included.
World Abstracts on Microelectronics and Reliability
Reliabilit) of thin fihn conductors and air gap crossovers
Prevention of bridging failure in mercury switches. JAMES
for hybrid circuits: tests, results and design criteria. G. F. F'IACI N IINI and G. M INLLLI. :~licroeh'clron. Reliab. 15, 451 [1976). The paper presents the results of a long study on the reliabilit\ of thin fihn conductors and cross-overs metallization for hybrid circuits. Three failure mechanisms are examined: clectromi{tration, humidily corrosion and mechanicallatique, which affi2ct the complex hybrid circuits as a consequence of the current h)ad. of the humidity and the electrical load and of the mechanical stresses induced by the encapsulant, For the humidity corrosion a new general quantitative formulation is proposed which relates temperature, poktrization and R.H. with medium time to fail. The agreement between the proposed tormulution and the results is verified both on unencapsulated and on encapsulated components and give an activation energy for NiCr Au or TiPdAu materials of q) 0.53 eV. Finally same cautelative design rules are proposed in order to have an acceptable reliability level from the design.
E. BENNETT, MICHAEL P. VAN DER WIELI'N, WALTER E, ASBELL and M. ROBERT PINt-;EL. lEE Trans. Parts, Hyhrids, Packa,qm,q PHP-12 (4), 380 (December 1976). Service failures of sealed mercury switches in relays may occur by "sticking" or by "'bridging." Analyses by scanning-electronmicroscope microprobe and by X-ray diffraction revealed that bridging fuilures in certain make-before-break-type switches can be due to the accumulation of particles of NiHg,, in the mercury which, because of increased viscosity, may form a quasi-steady bridge between the movable and fixed contacts. Doping of the mercury with copper and tin was proposed as a solution to the bridging problem based on the analysis of fulled switches and the knowledge gained from previous studies of liquid-mercury/solid-metal interactions. The results of an accelerated laboratory test and a field trial comparing the electrical characteristics o1 undupcd and doped switches confirm that the failure inechanism is thermally activated. The undoped switches were prone to bridging failure. Prevention of bridging failure in doped switches is attributed to the preferential formation of a tin-bearing layer which inhibits the dissolution of nickel and the subsequent formation of a viscous slurry of NiHg,,
Current gain degradation induced by emitter base avalanche breakdown in silicon planar transistors. A. J. MEHA. Microelectron. Reliah. 15, 619 (1976). The operation of silicon planar transistors under emitter base avalanche breakdown conditions can cause drastic reductions in current gain. Having investigated the dependence of the degradation rates on avalanche current for two types of n /->n transistor, the mechanism, carrier injection into the protective oxide is explained, and experimental data from tests on 300 transistors is compared with published theory.
Rubidium lamp stability and reliability for rubidium frequency standard. HITOSItl OYAMAI)A, KEIICHI TAKAHAStn, YOSItlKATSt SATO and H1SASHI UCIIIDA. NEC Res. Det~. 43, p. 69 (October 1976). Reliability. as well as frequency stability has come to be an important factor required for a rubidium gas cell frequency standard. Research has been conducted to determine what factors actually govern the reliability and frequency stability for a rubidium frequency standard. The research shows that the most important factor is the rubidium lamp performance, which is evaluated by the stability and profile of the radiant spectrum and by the light mteusily stability. These factors depend on lamp working conditions, such as exciting power and operating temperature as well as the manufacturing conditions. Therefore, to guarantee rubidium lamp quality, it is important to evaluate all these factors. The research shows that a change in light intensity is linear against a logarithmic time scale, and that its slope depends on exciting power and operating temperature. Research has been carried out to clarifs, the relation between life and exciting power. It also shows that life is in proportion to the minus 2nd to 3rd power of exciting power. In an attelnpt to determine the rubidium lamp failure rate, a continuous operation test has also been carried out. To date, there have been no failures, Therefore, its failure rate is less than 500 FITs and the realization of a highly reliable rubidmm lamp has become possible.
Stability and reliability of indium arsenide Hall Effect devices. R. MAN1EWSKI. Electron Technol. 9 (1), 45 (1976). A probabilistic description is given of a fixed set of technical parameters of the InAs (HA type) Hall effect devices made by lnstimte of Electron Technology. Both the parameters given and those not determined by producer but important for H E D applications, were studied. The results on ED stability were discussed and H E D reliability in respect to their parametric and catastrophic failures was estimated. Based on the obtained results it was possible to introduce somc changes in Polish H E D technology and to improve their quality.
il] nle rcl.lr }.
Bias influence on corrosion of plastic encapsulated device metal systems. BERNARD RIilCH. IEEE Trans. Reliah. R-25 (5), 296 (December 1976). Because of apparent anomalies noted on data recorded in tests conducted on P E D s (plastic encapsulated device) a re-examination of the influence of voltage biasing in temperature-humidity-bias testing has been conducted. Applied bias can have an important inIluencc on the reliability of plastic encapsulated transistors, depending on how it is applied. The analysis presented in this paper on the role of bias influence on PED failure rate explains some of the discrepancies that have been noted in the past by the author and other investigators.
Nondestructive SEM studies of Iocalised defects in gate dielectric films of MIS devices. O. K. GRWFITH. M. M. E. BEGUWALA and R. E. JOHN~)N. Proc. IEEE Reliab. Phys. p, 275 (April 1976). A nondestructive technique to identif~ localized defects in the gate dielectric of M O S devices has been developed. The technique is based upon electron beam induced conductivity modulation which gives rise to a relatively large increase in gate current under an applied bias when the beam scans a localized defect area. Measurements on devices with low gate breakdown voltage have been made and correlated with regions where subsequent catastrophic gate breakdown occurred. A circuit description and physical model of the technique is presented.
An improved approach to locating pinhole defects in MO S and bipolar integrated circuits using liquid crystals. CARMINt~ J. SALVO. Proc. IEEE Reliah. Phys. p. 263 (April 1976). Routine failure analysis of dielectric defects using nematic liquid crystals is possible with the method described in this paper. The refinements on previously described implementations result in excellent definition of the pinhole site. The paper discusses the principle involved in liquid crystal pinhole detection and details a practical liquid crystal fixture and device preparation. The influence of cell voltage polarity is illustrated and shown to be an important factor in achieving satisfactory results. The effectiveness of using dark field illumination and polarized light is shown and compared with the conventional bright field illumination used by prior authors. CMOS, M O S capacitor, and bipolar device analyses arc included.