Microelectronic System Reliability Prediction

The paper reviews the US MIL-HDBK-217 (MH-217) method of part stress-analysis failure-rate prediction for microelectronic systems and investigates the extent to which the MH-217 failure-rate formula is compatible with the physics of actual failure modes. A new formula is proposed which takes account separately of the reliability of the microelectronic devices in a system and of the system-level determinants of reliability. It is simpler than the current MH-217 formula, and more useful. It enables the system level aspects such as reliability program activities to be taken into account in the prediction, and allows better correlation to be made between part test and system test data. An example applies the new formula to a typical microelectronic system. By considering separately the failure physics of parts and the system level determinants, reliability prediction can be made a more useful tool both for part stress analysis and for reliability program management. The model would enable better correlations to be made between part and system test results. More work needs to be done to refine and validate the parameters. For high-reliability programs with closely controlled maintenance or with no maintenance, the use of a decreasing failure rate model for part failures should be considered. The failure rate formulae for other electronic parts used in microelectronic systems would also need to be reviewed, but apart from removal of the environmental factor and reduction in the failure rate values proportionate to that proposed for microelectronic parts, no changes should be necessary.     

The microprocessor failure rate predictions

A discrepancy is observed for the LSI failure rate model of the MIL-HDBK-217B. Handbook between a large gate count LSI device failure rate and the same device modelled by its parts namely MSI and SSI devices. A modified model is presented to show a close relationship in failure rates of small gate count LSI devices and to modify the results of higher gate count LSI devices using MIL-HDBK-217B data.     

BS 9000 components and reliability quality factors: Suggested use of MIL-HDBK-217C factors based on a comparative product assurance analysis

The calculation of electronic component failure rates using the MIL-HDBK-217C failure rate model requires an assessment of component quality - the πQ factor. Quality factors are not directly available for BS9000/CECC components and application of the MIL-HDBK-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 MODUS data bank of the University of Sheffield. Some of the problems and limitations of a CTR analysis are briefly mentioned.     

The use of MIL-HDBK-217 with the SCC EEE components

Data for reliability prediction are typically taken from MIL-HDBK-217 which lists failure rates against Military specifications.The practice however for parts procurement for ESA space systems relies amply on the SCC specifications. Test methods, qualification and screening programmes are thus peculiar to this system which utilises a blend of IEC and MIL test methods.Although many similarity exists between the Mil system and the SCC system, a direct correspondence between quality classes and testing levels (i.e. SCC levels B and C) from one system to another cannot in general be claimed. The use of MIL-HDBK-217 data under acquisition systems other than the MIL requires thus some reflection. Additionally, the use of MIL-HDBK-217 for reliability predictions on components with designation other than MIL obliges to adopt the quality factor corresponding to the class “lower” (i.e. non-MIL Spec).This implies in general penalising results for components qualified to standard classes like the SCCs, or components upgraded to military screening levels.Being MIL-217 undoubtedly the best source of failure rate information it can be used as reference for deriving quality factors (or more exactly quality factors scale coefficients to be used with parts procured to other systems.In the following the analysis of comparison of the EEE parts specifications is discussed. The scope of the analysis has been essentially to derive scale factors to use with the failure rates of MIL-hdbk 217 when the parts acquisition programme responds to the SCC requirements.     

Improved and accurate physics-of-failure (PoF) methodology for qualification and lifetime assessment of electronic systems

Assessing electronic systems' reliability using prediction handbooks (e.g. MIL-HDBK-217) can lead to wrong reliability predictions due to the assumption of a constant failure rate and the inaccuracy of the proposed semi-empirical models. Despite different initiatives since the last version of the most popular handbook MIL-HDBK-217 (1995) no fundamental improvement was realised that makes use of non-constant failure rate statistics – mandatory to model wear-out - and first principles based Physics-of-Failure modelling.Obtaining detailed PoF models requires physical insights and an extended experimental campaign to establish material properties. This is impossible to perform for a specific application.In this paper, we propose a methodology that combines the two approaches to get an improved reliability estimation and allows for a gradual improvement from a prediction handbook based approach to a PoF based reliability assessment. This methodology has been successfully validated on an industrial case.     

Automatic Electronic Component Failure-Rate Prediction with MIL-HDBK-217B

This paper describes a computer program and data base with automatic part failure-rate estimation according to MIL-HDBK-217B. The user supplies only a part list and application-dependent information. The program retrieves the part characteristics from the database, and computes the failure rate and power consumption for each part. Program options sum the failure rate and power requirements (dissipation) for the entire part list and perform trade-off analyses for different operating conditions or screening levels.     

RF ID智能卡可靠性预计模型的研究

通过对集成电路可靠性预计模型的理论和RF ID智能卡结构的研究,结合MIL-HDBK-217F,建立了RF ID智能卡可靠性预计模型,使RF ID智能卡研制进程有定量分析结果作为依据,避免了因缺乏实现可靠性、维修性指标所必须采取的技术措施,或因所采取的措施带有很大的盲目性而造成经济上和时间进度上的重大损失。     

MIL-HDBK-217F探讨

介绍美国国防部军用手册MIL-HDBK-217F,列出其相对于旧版本的改进项目,阐述手册目标及预计方法,分析可靠性预计局限性.     

A Method for Predicting VLSI-Device Reliability Using Series Models for Failure Mechanisms

A series model is used to determine the intrinsic reliability of an integrated circuit. An analysis of electromigration in the interconnect system of a 200 000 transistor VLSI device, shows that the failure rate exceeds 10 FIT (failures per 109 hours) within 2 years when operating at a temperature of 800 C. These results indicate the importance of fundamental wear-out mechanisms as factors in VLSI device reliability, under usual operating conditions. The analysis, as applied to a generic chip, predicts that temperature, burn-in, and complexity all adversely affect the device reliability. The paper demonstrates the feasibility of using the information available in the design database together with specific failure models to predict (during the design phase) the reliability of an IC. These techniques can be used to develop a CAD tool for reliability prediction.     

A comparison of electronic-reliability prediction models

One of the most controversial procedures in reliability is the use of reliability prediction techniques based on component failure data to estimate system failure rates. The International Electronics Reliability Institute (IERI) at Loughborough University is in a unique position. Over many years, much reliability information has been collected from leading British and Danish electronic manufacturing companies. These data are of such high quality that IERI can perform the comparison exercise with many circuit boards (CB) of different types. Several CB were selected from the IERI field-failure database and their reliability was predicted and compared with the observed field-performance. The prediction techniques were based on the: M217E [US Mil-Hdbk-217E]; HRD4; Siemens (SN29500); CNET; and Bellcore (TR-TSY-000332) models. For each model, the associated published failure rates were used. Hence, parts count analyses were performed on several CB from the database; these analyses were compared with the field failure rate. The prediction values differ greatly from the observed field behavior and from each other. Further analysis showed that each prediction model was sensitive to widely different physical parameters. The results are summarized. Some of the models are more sensitive to a factor that varies according to an Arrhenius model, such as temperature and electrical stress, while others are more sensitive to the discrete π factors used to model environment and quality     

高复杂度综合系统的可靠性预计

针对装备可靠性工作的焦点问题,在各个设备的可靠性要求的框架下,依据国家军用标准及美军标手册MIL-HDBK-217<电子设备可靠性预计手册>的应力分析法,采用比较实用、高效的ITEM ToolKit可靠性平台对某高复杂度仪器设备进行可靠性预计,在任务实施中探索一种比较实用、...     

SMT互连组件在热循环中的可靠性预计模型

电子设备中表面安装器件和电路基板以及焊接材料的热膨胀系数差异,使得SMT互连组件在热循环条件下产生热膨胀失配,在焊接处产生热应力,在长时间的交变应力的作用下,焊接处遭到疲劳破坏而使设备工作失效,这就是SMT互连组件在热循环条件下的基本失效机理。文中还介绍了美国MIL—HDBK—217F NOTICE Ⅱ公布的表面安装连接组件可靠性预测lSMT模型。给出一系列具有实用价值的参数。     

A new framework for part failure-rate prediction models

This paper presents a framework for developing part failure-rate models. It is a partial result of an effort sponsored by the US Air Force for the development of reliability prediction models for military avionics. Published data show that the existing reliability prediction methods fall far short of providing the required accuracy. One of the problems in the existing methods is the exclusion of critical factors. The new framework is based on the premise that essentially all failures are caused by the interactions of built-in flaws, failure mechanisms, and stresses. These three ingredients contribute to form the failure distribution which are functions of stress application duration (eg, aging time), number of thermal cycles, and vibration duration. The Weibull distribution has been selected as the general distribution. The distribution is then modified by the critical factors such as flaw quantities, effects of environmental stress screening, calendar-time reliability improvements, and vendor quality differences, to provide the part failure-rate functions. To provide credibility for the framework, only well published data and information have been used     

A parametric mixture-model for common-cause failure data [ofnuclear power plants]

This paper introduces a statistical reliability model for common-cause failure data from the nuclear industry. To achieve target reliability, many components in power plants are placed in parallel systems. The benefits of redundancy can be negated if multiple component failures occur due to a common external event. To model the possibility of multiple failures, a mixture-model based on the binomial failure-rate model is derived using reasonable assumptions of multiple failure events at a nuclear power plant (NPP). In many applications, the original binomial failure-rate model fits failure data poorly, and the model has not typically been applied to probabilistic risk assessments in the nuclear industry. This mixture-model fits better. This paper presents a least-squares solution to the mixture-model parameters and the model fit is investigated. Methods developed here are motivated by, and illustrated with, discrete failure data collected from several US NPP since about 1980     

A universal reliability prediction model for SMD integrated circuits based on field failures

This paper makes a review of integrated circuit field failures on three types of environment respectively, Ground Benign (G_B), Ground Fixed (G_F), and Airborne Inhabited Cargo (A_IC). It appears that for permanent working G_B, there was no package related failures and 2/3 of the failures had EOS origin. For G_F and A_IC most of the failures were open balls bonds and open solder joints. A universal predicting reliability model is therefore proposed for the die part and for the package part. This study has been carried out in the frame of a working group, to update the French standard UTEC 80810 (ex RDF93 from CNET), and is an alternative guide to the obsolete MIL-HDBK-217F for predicting reliability calculations.     

Reliability Evaluation and Prediction for Discrete Semiconductors

The use of accelerated step-stress and constant stress-in-time test techniques is demonstrated for generating models for predicting reliability at use conditions. Reliability prediction models were obtained for a signal diode, signal and power transistors, silicon trolled rectifier, and metal oxide varistor. Each of these device types follows the Arrhenius model for reliability prediction. Techniques are demonstrated for determining 1) the acceleration factor between extremely high acceleration testing conditions and field operating conditions on the signal diode; and 2) the acceleration or multiplying factor between high level stresses and use conditions which can be used to predict the performance of the signal diode over time. The effect of relative humidity on reliability is discussed. Devices under power operation have a lower relative humidity (RH) than the environment. This low RH suppresses humidity activated mechanisms. A transistor high-reliability screen which removes devices with early manufacturing type defects is described. This screen was effective, efficient and economical for improving the reliability of systems. A technique of combining acceleration factors for a number of items which affect reliability was demonstrated for the diode. This same technique should be useful for most device reliability predictions. The acceleration factors, however, can not be extrapolated into stress levels much above maximum ratings where new failure modes may appear that override the established failure rate relation with stress. The straight line plots of failure rates in this paper are terminated before these threshold limits.     

MOS Integrated Circuit Reliability

This paper presents information on the reliability of MOS integrated circuits based on p-channel enhancement-mode transistors, and describes their failure modes and mechanisms. The principal failure mechanisms were ion migration at the surface and oxide shorting. The results of experimental studies of the effects of variations in construction, processing, and levels of stress are presented, and are compared with other available information on MOS integrated circuit reliability. The failure rate for commercially available complex MOS arrays is on the order of 0.001 to 0.01 per 1000 h of operating life at 125°C for arrays containing approximately 600 p-channel transistors. This corresponds to a failure rate on the order of 5 × 10?6 to 5 × 10?5 per equivalent gate per 1000 h. The effects of device complexity, operating temperature, and other factors are discussed. A reliability prediction equation for MOS integrated circuits is derived from available information. An overall activation energy for functional failure mechanisms of approximately 5 kcal/mole (?0.2 eV/molecule) is considered applicable to typical MOS integrated circuits. Thus, the failure rate of MOS devices operated at 50°C ambient temperature can be predicted to be on the order of 10?6 to 10?5 per equivalent gate per 1000 h.     

考虑时间因素的不同基本门故障概率计算

在门级电路的可靠性概率评估方法中,基本门的故障概率p一般人为设定或以常数形式出现.考虑到不同基本门的故障概率具有随时间变化的特性并结合其输入导线,本文构建了考虑输入负载的随时间变化的不同基本门的故障概率模型.理论分析与实验结果表明,基于弱链接模型的双峰对数正态分布更适合用来表示输入导线故障概率的时间分布.用本文方法、美国军用标准MIK-HDBK-217及Monte Carlo方法计算了ISCAS85基准电路的可靠度并进行了比较,还通过了行业标准的检验,结果验证了本文所构建模型的合理性.     

Experimental power cycling on insulated TRIAC package: Reliability interpretation thanks to an innovative failure analysis flow

This paper presents the insulated TO-220AB TRIAC package aging when these devices are subjected to experimental power cycling test with various case temperature swings (ΔT_case). This study includes reliability tests set-up, results and failure analysis. An innovative failure analysis flow is proposed to identify the failure mechanism implied. This new failure analysis process flow is necessary due to the complex stack of these devices. Finally, thanks to the reliability tests and the complete failure analysis results, the thermal resistance (R_th) change is correlated to the physical defect modification. This whole study gives the first data collection that is required to propose a lifetime prediction model for insulated TO-220AB TRIAC package during power cycling accelerated aging tests.     

结合版图结构信息的基本门电路故障概率估计

在门级电路可靠性估计方法中,基本门的故障概率P一般采用经验值或人为设定.本文结合基本门的版图结构信息,综合考虑了设计尺寸及缺陷特性等因素,分析了不同缺陷模型下的粒径分布数据,给出了缺陷模型粒径概率密度分布函数的参数c的计算算法,并推导出了P的计算模型.理论分析与在ISCAS85及74系列电路上的实验结果表明,缺陷的分段线性插值模型能较准确地描述电路可靠性模型的低层真实缺陷.对ISCAS85基准电路采用本文方法所得到的电路可靠度与采用美国军用标准MIL-HDBK-217方法所得到的计算结果进行了比较,验证了本文所建P模型的合理性.