Three-step concept (TSC) in modeling microelectronics reliability (MR): Boltzmann–Arrhenius–Zhurkov (BAZ) probabilistic physics-of-failure equation sandwiched between two statistical models

When encountering a particular reliability problem at the design, fabrication, testing, or an operation stage of a product’s life, and considering the use of predictive modeling to assess the seriousness and the likely consequences of the a detected failure, one has to choose whether a statistical, or a physics-of-failure-based, or a suitable combination of these two major modeling tools should be employed to address the problem of interest and to decide on how to proceed. A three-step concept (TSC) is suggested as a possible way to go in such a situation. The classical statistical Bayes’ formula can be used at the first step in this concept as a technical diagnostics tool. Its objective is to identify, on the probabilistic basis, the faulty (malfunctioning) device(s) from the obtained signals (“symptoms of faults”). The recently suggested physics-of-failure-based Boltzmann–Arrhenius–Zhurkov’s (BAZ) model and particularly the multi-parametric BAZ model can be employed at the second step to assess the remaining useful life (RUL) of the faulty device(s). If the RUL is still long enough, no action might be needed; if it is not, corrective restoration action becomes necessary. In any event, after the first two steps are carried out, the device is put back into operation (testing), provided that the assessed probability of its continuing failure-free operation is found to be satisfactory. If the operational failure nonetheless occurs, the third, technical diagnostics step should be undertaken to update reliability. Statistical beta-distribution, in which the probability of failure is treated as a random variable, is suggested to be used at this step. While various statistical methods and approaches, including Bayes’ formula and beta-distribution, are well known and widely used in numerous applications for many decades, the BAZ model was introduced in the microelectronics reliability (MR) area only several years ago. Its attributes are addressed and discussed therefore in some detail. The suggested concept is illustrated by a numerical example geared to the use of the prognostics-and-health-monitoring (PHM) effort in actual operation, such as, e.g., en-route flight mission.     

Reliability enhancement by integrated liquid cooling in power IGBT modules for hybrid and electric vehicles

Insulated Gate Bipolar Transistor (IGBT) modules in power train system of Hybrid and Electric Vehicles (HEV/EV) are working in harsh environment and high reliability and long lifetime are required. In this work, reliability enhancement by integrated liquid cooling structure in HEV/EV IGBT module is investigated. The thermal resistance of junction to heat sink can be reduced more than 50% by direct liquid cooling as eliminating thermal grease layer, so both active and passive temperature swings decrease significantly which will enhance module reliability and lifetime. The lifetime of modules with conventional and integrated liquid cooling structures are estimated under mission of standard driving cycles. We found that lifetime is prolonged obviously by direct cooling pin–fin base plate, and the compact module also makes the application power system simple and reliable.     

Interface microstructure effects in Au thermosonic ball bonding contacts by high reliability wire materials

Palladium-doped and (Cu, Pt)-doped high reliability gold wires were used to form wire bond interconnects on aluminum IC metallization. By isothermal annealing of wire bond samples the formation of intermetallic Au–Al phases was stimulated. SEM/EBSD investigations of the phase regions exhibited significantly slower isothermal growth rates compared to a reference gold wire. Correlated TEM, STEM–EDXS and nanobeam diffraction analyses revealed that Pd is preferentially incorporated into the Au₈Al₃ intermetallic forming a new stable phase but additionally can obviously form a new Pd-rich ternary intermetallic. In comparison, Cu dopants are also accumulated into a new Al–Au–Cu phase while Pt is rather found agglomerating within grain boundaries and interfaces. These results suggest a diffusion barrier model that allows discussing how wire doping can affect the bond contact microstructure, thus increasing the lifetime of bond contacts.     

High temperature reliability of electrically conductive adhesive attached temperature sensors on flexible polyimide substrates

The attachment and packaging of temperature sensors may be challenging due to their structure and materials. Sensing requires a structure which is open to the environment and the materials often differ from those used in silicon-based electronics. Thus, traditional attachment techniques and materials such as soldering may be inappropriate. Polymer-based electrically conductive adhesives (ECA) are an alternative. The operating environment of a sensor may, however, be very demanding. Very little research data is available on the use of ECAs in challenging conditions, thus restricting their use in many applications. This study tested the behaviour of temperature sensors attached with ECAs onto flexible polyimide (PI) substrates in thermal storage at 200 °C. More than 1000 h of testing without failures were conducted on the ECA sensor structures. Good high temperature reliability therefore seems to be possible with ECAs. However, the PI substrate was observed to be critical to reliability. An adhesive layer used in the PI substrate reacted at the test temperature and severe oxidation of the copper pads and reaction between the materials consequently destroyed the interconnection and caused failures.     

NON-DESTRUCTIVE PAVEMENT LAYER THICKNESS MEASUREMENT USING EMPIRICAL MODE DECOMPOSITION WITH GPR

Ground Penetrating Radar （GPR） is an effective Non-Destructive Testing （NDT） technique for highway pavement surveys, which is able to acquire continuous pavement data compared with traditional core drilling method. In this study, we proposed an accurate and efficient method to estimate the thickness of each pavement layer using an air-coupled GPR system. For this work, the main difficulties are estimating each pavement layer＇s time delay and dielectric constant. We first give the basic signal model for pavement evaluation, and then present an Intrinsic Mode Functions （IMFs） product detector to determine each pavement layer＇s time delay. This method is based on Empirical Mode Decomposition （EMD）, which is an adaptive signal decomposition procedure and proved to be suitable for suppressing noises in GPR signal. The dielectric constant was determined by metal reflection measurement. The laboratory and highway experiments illustrate that the proposed thickness estimation method yields reasonable result, thus meets the requirements of practical highway pavement survey with massive GPR data.     

全自动太阳能电池测试分选设备的研制

太阳能电池测试分选设备是晶体硅太阳能电池生产专用设备,可用于太阳能电池转换效率以及电性能参数测量。所有的测量结果可以自动分类,自动保存。该设备在测试系统设计、分选结构设计、步进电机精密驱动、高速数据交换和电气控制等技术方面达到较高水平。该设备具有全自动化,操作简便,测试精确,运行稳定,碎片率低、生产效率高等特点,性能完...     

E-Bayesian estimation of the reliability derived from Binomial distribution

This paper introduces a new parameter estimation method, named E-Bayesian estimation method, to estimate reliability derived from Binomial distribution. The definition of E-Bayesian estimation of the reliability is proposed, the formulas of E-Bayesian estimation and hierarchical Bayesian estimation of the reliability are also provided. Finally, it is shown, through a numerical example, that the new method is much simpler than hierarchical Bayesian estimation in practice.     

风力发电机控制系统的可靠性设计

风力发电机控制系统作为风力发电机系统的核心,对于控制系统的可靠性研究是有很重要的现实意义。本文提出了风力发电机控制系统的可靠性设计,包括变桨系统、偏航控制、励磁系统、变流系统、雷电保护和冗余系统。本文将可靠性设计的方法应用到风力发电机控制系统的设计上,大大提高了机组的可靠性。     

光清洗技术在雷达微组装方面的应用

在生产雷达微电子组件时,由于各种原因,会在组件当中留下人体残留的油脂、头皮屑、焊膏的残留物和松香焊剂残留物等,这些多余物不仅可能对组件造成腐蚀,还会引起电路短路和电气误动,影响金丝键合的附着力,这些多余物不清洗干净将严重影响雷达微电子组件的长期工作寿命和使用可靠性。雷达微电子组件由于采用高度精密的微组装技术,显得既复杂...     

多线程同步技术在电感自动测试系统中的应用

多线程同步技术能够更好地开发并行性任务和提高系统性能.为实现高速的仪器测量与低速的机械动作之间的有机协调,提高工作的效率,在研究了Windows线程同步机制和CVI多线程技术中数据保护的基础上,给出了利用事件内核对象和线程安全变量来实现电感自动测试系统的方法,同时给出了工作线程的流程图.实际使用结果表明:该系统对单台测...