采用激光束加热法检查VLSI布线缺陷

NEC开发了非破坏性的检查由电迁移和应力迁移造成的布线过程中产生的缺陷（空隙：Void）的新方法（OBIRCH：OpticalBeamInducedResistanceCHange，光束加热电阻变化检查法）。OBIRCH法是：采用激光束加热使布线电阻发生变化，其变化程度根据有无缺陷及其大小而不同；利用这一点，用图象显示缺陷位置及大小。例如，采用此方法可清楚地检查出布线宽为Zpm时，隐理在布线中的0．4Hm宽的空隙。近而，采用NB（聚束离子束）的断面薄片验证。确认隐理的空隙。结果，证实了也可检出0．IPm的空隙。作为OBIRCH法应用一例是观测电迁移造成…     

铜互连电迁移失效的研究与进展

Cu/低k互连的电迁移失效与互连材料、工艺、结构和测试条件都有着密切的联系。论述了近年来铜互连电迁移可靠性的研究进展,讨论了电迁移的基本原理、失效现象及其相关机制和微效应以及主导失效的机制——界面扩散等,同时探讨了改善铜互连电迁移性能的各种方法,主要有铜合金、增加金属覆盖层及等离子体表面处理等方法,并指出了Cu互连电迁移可靠性研究有待解决的问题。     

VLSI金属互连线电迁移噪声检测敏感性的逾渗模拟

在电迁移物理机制的基础上结合逾渗理论,建立了一种金属互连线电迁移的逾渗模型。基于该模型,采用蒙特卡罗方法模拟了超大规模集成电路（VLSI）金属互连线电迁移过程中电阻和低频噪声参数的变化规律。结果表明,与传统的电阻测量方法相比,低频噪声表征方法对电迁移损伤更敏感,检测的效率更高。该研究结果为低频噪声表征VLSI金属互连线电迁移损伤的检测方法提供了理论依据。     

Cu-Ni/Solder/Ni-Cu互连结构的电迁移

采用Cu-Ni/Solder/Ni-Cu互连结构,在加载的电流密度为0.4×104 A/cm2的条件下,得到了界面阴极处金属原子的电迁移.数值模拟揭示了其原因是由于凸点互连结构的特殊性,电子流在流经凸点时会发生流向改变进而形成电流聚集,此处的电流密度超过电迁移的门槛值,从而诱发电迁移.运用高对流系数的热传导方法降低了互连焊点的实际温度,在电迁移的扩展阶段显著减小了高温引起的原子热迁移对电迁移的干扰;因此电迁移力是原子迁移的主要驱动力.在电迁移的快速失效阶段,原子的迁移是热迁移和电迁移共同作用的结果:电迁移力驱动阴极处原子的迁移,造成局部区域的快速温升,从而加剧此处原子的热迁移.     

Cu-Ni/Solder/Ni-Cu互连结构的电迁移

采用Cu-Ni/Solder/Ni-Cu互连结构,在加载的电流密度为0.4×104 A/cm2的条件下,得到了界面阴极处金属原子的电迁移.数值模拟揭示了其原因是由于凸点互连结构的特殊性,电子流在流经凸点时会发生流向改变进而形成电流聚集,此处的电流密度超过电迁移的门槛值,从而诱发电迁移.运用高对流系数的热传导方法降低了互连焊点的实际温度,在电迁移的扩展阶段显著减小了高温引起的原子热迁移对电迁移的干扰;因此电迁移力是原子迁移的主要驱动力.在电迁移的快速失效阶段,原子的迁移是热迁移和电迁移共同作用的结果:电迁移力驱动阴极处原子的迁移,造成局部区域的快速温升,从而加剧此处原子的热迁移.     

几种电迁移（Electro migration）寿命评估方法的探讨

电迁移失效是影响大规模电路可靠性的一个重要因素，通过电迁移的可靠性实验可以评估它的寿命。本文介绍了三种不同的评估方法，比较了它们的优缺点和近似条件，并用实例比较了相应的评估结果，使读者在评估电路电迁移寿命或进行电迁移实验时对三种方法有一个正确的选择。     

铜互连电迁移可靠性的研究进展

综述了近年来铜互连电迁移可靠性的研究进展;讨论了电迁移的基本原理、常用研究方法及主要失效机制;探讨了改善铜互连电迁移性能的各种方法,如铜合金、增加金属覆盖层及等离子体表面处理。最后,指出了铜互连可靠性研究中存在的问题。     

电子封装无铅互连焊点的电迁移研究进展

随着电子封装逐渐向小型化和多功能化发展,互连焊点中的电迁移问题备受关注。本文针对电子封装无铅互连焊点中出现的电迁移问题,先探究了电迁移的影响因素,其中包括电流密度、温度、焊点的成分和微观结构。其次,阐述了电迁移对无铅焊点的力学性能、界面组织、振动疲劳性能和断裂机制的影响。然后针对电迁移问题,介绍了通过添加合金元素和控制电流密度两个方面来提高焊点的抗电迁移失效的能力。最后,简述了该领域的研究发展方向,为进一步研究电迁移对无铅互连焊点的可靠性提供了理论基础。     

集成电路互连引线电迁移的研究进展

随着大规模集成电路的不断发展,电迁移引起的集成电路可靠性问题日益凸现.本文介绍了电迁移的基本理论,综述了集成电路互连引线电迁移的研究进展.研究表明,互连引线的尺寸、形状和微观组织结构对电迁移有重要影响;温度、电流密度、应力梯度、合金元素及工作电流模式等也对电迁移寿命有重要影响.同时指出了电迁移研究亟待解决的问题.     

VLSI金属互连电迁移可靠性评估技术研究

在简要介绍电迁移失效机理的基础上,对各种电迁移可靠性实验评估方法的特点进行了分析对比,重点研究了VLSI金属互连电迁移可靠性的噪声评估技术.通过实验数据和结果的对比分析,证明噪声方法不仅可行,而且有着其他传统方法不可比拟的优越性,具有极好的应用前景.     

微纳薄膜器件的电阻率精确测量方法

微纳级别的铝薄膜因宽度和厚度尺寸缩小其试件尺寸接近电极的最小间距、电极间的位置误差等因素的影响,导致电阻率四电极法在测量过程中产生较大的误差。通过对微纳级的导电薄膜的四电极测量法进行数学建模分析,建立了新的四电极测量法数学计算模型,提供精确的电阻率修正系数,并利用基于原子力显微镜的四电极电阻率测量技术精确测量了厚度为400 nm、宽度为30μm的铝薄膜的电阻率,且取不同的作用力重复实验。实验结果证明,基于修正后数学模型的微四电极技术对微纳级别薄膜的电阻率测量方面的准确性和稳定性。     

Dielectric Reliability Measurement Methods: A Review

Reliability of thin dielectric films such as silicon dioxide grown on single crystalline silicon is of great importance for integrated circuits of present and future technologies. For the characterization of the quality of dielectric films, it is essential to have measurement methods available which can give a measure of dielectric reliability in a relatively short time. Stress biases are usually highly accelerated and cause destructive dielectric breakdown. Testing for dielectric reliability has been performed for more than 30 years, and in that time many different stress methods have been established. This article reviews that most common dielectric reliability measurement methods and gives practical guidelines to the reliability engineer in the field of dielectric characterization. The examples and data shown here are mainly from MOS gate oxides. The aim of this review paper is to emphasize advantages and disadvantages of the various stress methods. Appropriate dielectric stress methods are pointed out for applications such as process development, process characterization, pocess control and screening (burn-in). A broad number of different measurement techniques are described in detail for which the set up of the measurement and its stress parameters are clarified. Suitable dielectric test structures and the determination of the correct voltage and thickness of the dielectric are discussed; they are essential to determine the electric field across the thin film. The identification of dielectric breakdown and the interpretation and significance of the measurement results are reviewed. A good understanding of the stress method and the various measured parameters is essential to draw correct conclusions for the lifetime of the dielectric at operating conditions. The commonly used, basic analysis techniques for the measurement results are illustrated. Finally, the influence of stress-induced leakage currents on the dielectric reliability characterization is discussed and other aspects relating to very thin oxides of future technologies are briefly described. The paper also includes a large bibliography of more than 250 references.     

Micro-mechanical testing of SiLK by nanoindentation and substrate curvature techniques

Advanced micro-mechanical characterization methods provide material properties of thin films for modeling thermo-mechanical behavior of thin films for micro-electronic applications. Here, we focus on the local measurement method of nanoindentation for finding visco-elastic properties, and a global method of substrate curvature testing that provides linear elastic properties. Our specimen SiLK, Dow chemicals, is a low-k dielectric thin polymer film with a thickness of 400 nm, 6 and 8 μm, deposited on Si substrate. Our results show temperature dependent linear elastic and linear visco-elastic material properties for thin film materials.     

Measurement of microwave surface resistance of patterned superconducting thin films

A simple and versatile measurement technique has been demonstrated for characterization of thin film superconductors and the substrates on which they are deposited. Unlike other state of the art measurements that characterize only the top layer of unpatterned thin films in end-plate replacement or perturbation-type cavity arrangements, we test the sample under conditions very close to those of actual microwave circuit applications. Measurements on a laser deposited, thin-film YBCO superconductor, patterned in the form of a meander line on a LaAlO₃ substrate, show a microwave surface resistance one order of magnitude lower than that of copper at 79 K and 11 GHz. At 1.4 GHz and 79 K, an improvement by over two orders of magnitude is observed. This is the first demonstration of superior microwave performance of a comb filter structure using a HTS thin film. The research portion performed at Sarnoff was supported by the Strategic Defense Initiative Organization under Contract SDIO84-88-C-0044.     

薄膜磁致伸缩系数测试系统的研究

根据激光光杠杆放大原理设计实现了薄膜磁致伸缩系数的计算机辅助测试系统。根据激光光杠杆的放大作用,利用位置敏感传感器(PSD)探测激光光点的位移,将激光点位移信号转换成电信号,利用KEITHLY2182电压表测量电信号,在Testpoint测试软件平台上开发了磁致伸缩系数测试程序,通过计算机对KEITHLY2182电压表的控制,实时读出KEITHLY2182电压表所测到的电压并进行数据处理。通过标定,该测试系统能较好地对薄膜磁致伸缩系数进行测量。     

一种用于薄膜热容测量的微热量计的设计与制作

目前已发现并证实薄膜的热导率和热扩散率存在着尺寸效应。本文为了研究薄膜的另一个热学性质比热是否也具有尺寸效应 ,提出了一种用于薄膜热容测量的新方法 ,其相应的实验器件为一悬膜结构。从理论上阐述了其测量原理 ,结合ANSYS热学模拟设计并利用微机械加工技术制作出SiO2 悬膜结构 ,悬膜由两个悬臂支撑 ,在悬膜上制作了Pt薄膜电阻同时用于加热和测温。这种结构加快了样品、悬膜和加热 /测温电阻之间的热传递 ,减小了悬膜的热损失 ,提高了测量精度。     

Characterization of Ultrathin Dielectric Films With the Prism-Coupler Method

We demonstrate a technique of applying the prism-coupler method to the characterization of dielectric films that are too thin to support enough guided modes in air for the normal application of the method. The technique is based on applying suitable index-matching liquids on the surface of the thin film to increase the number of effective indexes available for the determination of the refractive index and the thickness of the film. With this technique, even thin films that do not support any guided modes in air can be characterized. We apply the technique to the characterization of polymer thin films as thin as 100-200 nm and discuss its performance and limitation     

基于原位共角椭偏与反射谱的TiO2薄膜光学常数分析

为了分析溶胶-凝胶法制备的TiO₂薄膜的光学常数,采用旋涂法制备了多层TiO₂薄膜,利用扫描电镜对表面形貌进行了分析,利用椭圆偏振光谱对薄膜的折射率色散和孔隙率进行了拟合分析,并利用原位共角反射光谱对拟合结果进行了验证,得到了TiO₂薄膜厚度、孔隙率和折射率色散曲线。结果表明,TiO₂薄膜厚度与旋涂层数成线性关系,薄膜孔隙率约为15%且与旋涂层数无关,New Amorphous色散模型可以较好地拟合溶胶-凝胶旋涂方法制备的TiO₂薄膜在1.55eV~4.00eV波段的椭偏光谱。该研究为溶胶-凝胶法制备的TiO₂薄膜的光学常数测量提供了参考。     

Millimeter-wave permittivity measurement of deposited dielectric films using the spherical open resonator

A differential method using the spherical open resonator is developed for permittivity measurement of a thin dielectric film on an optically dense substrate. It is based on a measurement of the resonant frequency shift due to the thin film on the substrate. The accuracy of the method is demonstrated to be about 4% for a 5.6-/spl mu/m photoresist film at 142 GHz.     

一种气相沉积薄膜TEM样品制备技术——改进的可溶盐基片法

本文对可溶盐基片方法制备薄膜TEM样品进行了改进。改进后不仅保持了原可溶盐基片法方便、高效和快捷的特点,还可以根据表征需要获得薄膜在不同生长阶段微结构的样品。