电子元器件的贮存可靠性研究

【作者】 杨少华；

【导师】 吴福根；

【作者基本信息】 广东工业大学 ， 物理电子学， 2006， 硕士

【摘要】 电子元器件贮存状态下的可靠性,对于“长期贮存,一次使用”的军用电子装备而言,具有重要意义。通过开展电子元器件的长期贮存试验,对其进行考核和评价,使之能为装备可靠性设计提供参考、依据和基础数据,是一项重要的任务。 首先,介绍了贮存状态下环境应力对电子元器件的影响。详细论述了热效应、化学效应、及辐射损伤等对器件的影响。器件内部材料的热不匹配是热应力产生的内因,贮存环境温度变化是外因。化学效应能对器件的外引线、封装、及芯片内部的金属化系统、金-铝接触、内引线等造成腐蚀。 其次,论述了电子元器件两种贮存可靠性评价的方法:自然贮存评价和加速应力评价,同时也详细介绍了本研究的试验方案。根据目前的试验结果,总结了失效率数据,同时也统计分析了器件在贮存期间性能变化,以及不同贮存地区之间非工作可靠性的差异。 第三,研究了电子元器件贮存状态下的失效模式和失效机理。试验结果表明,腐蚀、键合缺陷和贴装失效是造成器件非工作失效的主要原因。并根据试验中暴露的失效模,分析原因、提出了相应的设计改进措施,以提高其固有可靠性。 最后,试验数据的处理以及寿命预测方法的研究一直是本研究的难题,至今国内外没有成熟的方法和标准可以参考,这里借鉴了其他方法在预测上的应用,引入灰色系统理论和BP神经网络模型来处理试验数据,预测其贮存寿命。预测结果表明具有一定的准确性。这在寿命预测方法上进行了新的探索,但是它是建立在数据统计基础上的,应进一步考虑与失效物理模型的相结合。更多还原

【Abstract】 For military electric equipments that "long-term storage, once use", the non-reliability of electric components play an important part in them. With carrying out the long-term storage experiments, a mainly purpose is to evaluate the component non-operating reliability, as well as to provide design conferences and guidelines and basic data for the equipment reliability.First, environmental effects on electric components are introduced. The thermal effect, chemical effect and radiative effect are discussed in detail. The inner material thermal mismatch of components is an inherent reason to cause thermal effect;furthermore, the storage ambient temperature change is the external cause. Chemical effect may erode the pins, packages, internal metal system, Al-Au contacts and inner bonding of the device.Second, Two kind of methods for electric components non-reliability evaluation, storeroom storage evaluation and accelerated stress method are discussed. Meanwhile, the experiment technique in this study is illustrated in detail. To sum up the current experiment results, the component failure rate is obtained. Beside, whether the functional parameters of the device during storage period are diversified distinctly was analyzed, as well as whether there exist significant differences among four storage regions.Third, the failure modes and failure mechanisms of electric components under the non-operating condition is investigated. Experiment results indicated that the corrosion, bonding failure, fixture and package failure are the mainly causes to induce components failures. According this failure modes and failure mechanisms exposed during experiment, many corresponding improvements in design and manufacture stage were put forward to enhance the inherent reliability of the devices.Finally, since the storage data processing methods and storage life predicting techniques have been the barrier of the study, there are no perfect techniques forreference. Considering the advantage of other methods applied in prediction, the gray system theory and BP neural network were introduced in this study to predict the storage life. The prediction results indicated that it has certain precision and it may explore a new technique on the storage life prediction. But those two methods are based and localized on the data statistical processing. It should consider more the combination with failure physics model.更多还原