共查询到20条相似文献,搜索用时 125 毫秒
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金丝材料应用于航天器小型化微波模块等产品的电路封装中,金丝键合界面受高低温环境影响易产生性能变化从而影响服役可靠性。本文对金丝界面高低温特性的演化规律进行了研究,包括空间温度环境模拟试验后的界面与成分迁移、界面层厚度变化、键合金丝拉伸剪切力与失效模式演变,得出不同温度条件处理后的金铝键合界面微观组织变化规律。结果表明高低温循环试验后金丝界面仍保持较高的结合强度,一定程度的金属间化合物生长提高了键合界面强度。高温贮存试验中,随着贮存时间的增加,金丝界面层IMC(Intermetallic Compound)厚度和金属间化合物不断增长,失效破坏位置越来越多地出现在键合界面处,铝金属化层附近的金含量因扩散而增高,金铝键合界面处IMC界面层厚度的增加降低了界面结合强度。 相似文献
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为了保证陶瓷栅格阵列(CLGA)封装器件装联可靠性,本文以CLGA封装器件为研究对象,采用Pb90Sn10焊球、Pb90Sn10与Pb80Sn20焊柱、Be-Cu/Sn60Pb40微弹簧圈(MCS)和Sn63Pb37共晶焊料,实现了对CLGA封装器件的二次工艺设计,并采用回流焊工艺方法将器件装联在印制电路板上。通过有限元分析及试验相结合的方法,探索了适用于此类器件的高可靠性装联工艺。对3种元器件建立有限元仿真模型来模拟应力应变情况,同时对印制板组件进行了力学、热学实验分析。仿真发现:弹簧所受的应力和应变最小,焊柱其次,焊球最大;试验验证与仿真结果相符:植弹簧的器件可靠性最高,植焊柱的其次,植焊球的最差;500个温度循环与振动试验表明:植弹簧器件无裂纹,植焊柱、植焊球的器件出现裂纹,焊点金相剖切与SEM能谱显微组织分析均符合航天标准要求。植焊球、植焊柱的器件焊点断裂失效位置均出现在焊球、焊柱与钎料印制板接触的位置,且裂纹处金属间化合物(IMC)层厚度与能谱成分未见异常。 相似文献
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针对当前国内外诱发静电放电(ESD)研究较少的实际情况,为了解自然环境下静电放电辐射场诱发放电的基本特性,进一步分析诱发放电的特征规律,建立了大气条件下诱发放电试验系统。主要采取理论分析、试验验证的方式,对静电放电辐射场诱发针-球电极结构放电的基本规律进行摸索,初步得出了诱发放电的基本规律。研究结果表明:在外界条件一定的情况下,随着辐射场强的不断增大,放电重复频率不断增大;在辐射场强一定的情况下,随着高压源电压的不断增大,诱发放电重复频率不断增大;在外界环境条件一定的情况下,能够确定该条件下的诱发放电唯一阈值。这些试验规律的取得,为真空条件下的诱发放电特性研究提供了试验方法和理论依据,对开展航天器运行环境中的诱发放电研究和防护方法设计具有重要意义。 相似文献
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介绍了飞机燃油箱爆炸的防护手段,在消除静电放电产生点火源方面,分别从消除静电产生、促进静电荷流散、避免静电放电三个方面总结了飞机燃油箱静电打火的防护方法。 相似文献
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静电是航空燃料使用中的常见现象,而静电的危害则是由于静电的力学现象和放电现象所引起的。由于积聚的电荷构成的电场而产生的电场力对周围微粒产生吸引作用,如粉尘、纤维等,会造成生产中的故障。静电放电则可引起可燃气体的燃烧或爆炸,是航空燃料使用中的主要危害。若防护不当引起爆炸或着火,就会造成人员伤亡及经济损失。因此,静电防护具有非常重要的意义。 相似文献
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Wright R.G. Zgol M. Keeton S. Kirkland L.V. 《Aerospace and Electronic Systems Magazine, IEEE》2001,16(6):15-19
This paper describes original research efforts in the design, simulation, and development of nanotechnology-based molecular test equipment (MTE). This is a research effort for testing printed circuit boards independent of traditional automatic test equipment (ATE) through the fabrication of MTE within integrated circuits (ICs). The MTE is embedded within the IC substrate and encapsulated within nanoprobes that connect between the surface and the substrate of the IC at various functional areas. A process is followed whereby IC device simulation is performed to assess the electrical, chemical, and structural properties of integrated and adjacent substrate devices. Through this approach the nominal and failed device performance parameters of interest to substrate-based MTE are found. Discussion of the development and application of MTE within IC architectures is provided, including such topics as the effect of substrate composition on the design and realization of MTE, interfaces between MTE and IC devices, and reporting of MTE results to the IC surface and technician. Potential application areas within different device functions will also be identified. A chemical structure diagram is also provided to illustrate the implementation of MTE using discrete device configurations with MTE-augmented logic 相似文献
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Keenan E. Wright R.G. Zgol M. Mulligan R. Tagliava V. Kirkland L.V. 《Aerospace and Electronic Systems Magazine, IEEE》2004,19(6):9-15
This paper describes research and development efforts in the use of infrared (IR) laser beams for detecting failures in integrated circuits resident on printed circuit boards. This work involves taking advantage of the transparency of the silicon substrate of ICs to radiation in the near infrared (NIR) spectrum to devise a non-invasive method for imaging the component circuitry of the IC. The implication is that a means to see into the physical structure of an integrated circuit can be created by using lasers tuned to these wavelengths. While the silicon substrate is transparent to the laser, the circuit paths and devices embedded within the substrate are readily visible since their metallic composition is opaque to laser energy at this wavelength. A laser test fixture consisting of a 1064 nm continuous wave laser, CCD camera, and image acquisition board is used to generate images from flip-chip integrated circuits. Multiresolution image processing techniques are then applied to the resulting images to identify potential defects. 相似文献
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介绍了DPA—Switch芯片的外部引脚、内部电路及功能模块;讲解了同步整流电路的基本工作原理。根据DPA—Switch的特性给出了同步整流开关电源的设计方法和具体的设计电路,并对外围电路的设计进行了分析,最后给出了测试结果及设计注意事项。 相似文献
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以焊接无铅BGA器件为目的,在三种主要焊接工艺方法中选择有铅焊料焊无铅BGA的工艺方法.通过调整回流焊炉各温区参数,得到适用于这种工艺方法的温度曲线,并通过外观、X射线、染色与渗透、剪切力、金相剖切对焊接质量进行分析.分析结果表明:该工艺方法焊接的无铅BGA焊点外观符合目检要求;X射线下没有发现焊点的明显缺陷;环境试验后,焊点的剪切力符合标准要求;染色试验未发现被染色的焊球;焊点的金相图显示结合处焊接良好,且满足合格焊点的金属间化合物厚度要求(0.5~50 μm),这种工艺方法能够较好的完成无铅BGA器件的焊接,有一定的应用价值. 相似文献
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Pitch, roll, and yaw moments can be developed by deflecting and changing the geometry of control surfaces. In this paper, smart flight control surfaces are designed using multi-node microelectromechanical systems (MEMS) to displace control surfaces and change the surface geometry. These MEMS augment translational motion microstructures (actuators-sensors), controlling/signal processing integrated circuits (ICs), radiating energy devices and antennas. The desired pitch, roll, and yaw moments are produced, drag can be reduced, and unsteady aerodynamic flows are controlled by smart flight control surfaces. That is, we achieve aerodynamic moment and active flow control capabilities. The major objective here is to report fundamental and applied research in design of smart flight control surfaces with MEMS-based actuator-sensor-IC arrays controlled by hierarchical distributed systems. We demonstrate the feasibility and effectiveness of the application of smart flight control surfaces for coordinated longitudinal and lateral vehicle control 相似文献
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Unique research efforts relating to the development of nanoscale devices to replace standard integrated circuits, and eventually entire electronic systems. Standard integrated circuits (IC) have limitations or restrictions in size, speed, reliability, complexity and finding suitable replacements for discontinued items. Nanoscale device development and understanding has dramatically grown. One of the key properties of quantum physics that quantum computers rely on is the ability of certain atoms or nuclei to work together as quantum bits. These computing devices are a fraction of the size of typical ICs (nanoscale). Nanoscale devices developed using quantum physics principles have unlimited potential to revolutionize the methods and design of fabricated printed circuit cards and complete systems. They can replace an entire PC board or the set of PC boards that comprise a Line Replaceable Unit (LRU). This would be a good and practical jumping-off point to going directly to the complete device, system, or function level. This might include a nanoscale computer (general purpose or flight control), transmitter, GPS receiver, position and/or attitude sensors in either a stand-alone configuration, or combined within conventional devices (e.g., a nanoscale communications suite (xmtr/rcvr, etc.)) encapsulated within the Plexiglas canopy or the control yoke of an F16 rather than behind the instrument panel or maybe the whole comm suite into the pilot's helmet. 相似文献