基于成团效应的众核处理器失效核分布建模方法

随机产生失效核分布的方法不能反映众核处理器物理拓扑结构的真实状况,在评价相关拓扑重构算法的效能时有失客观性.本文针对这一现状,提出了一种基于缺陷成团效应的众核处理器失效核分布建模方法.实验表明,本方法得到的物理拓扑结构缺陷分布呈现出不同程度的成团特性,且成团效应会显著影响核级冗余技术的拓扑重构效果.     

集成电路局部缺陷模型及其相关的功能成品率分析

大规模集成电路（VLSI）使亚微米特征尺寸的大面积集成电路制造以及集成数百万个器件在一芯片上成为可能。然而,缺陷的存在致使电路版图的拓扑结构发生变化,产生IC电路连接错误,导致电路丧失功能,从而影响IC的成品率,特别是功能成品率。文章主要对缺陷的轮廓模型、空间分布模型和粒径分布模型作了介绍;对集成电路成品率的损失机理作了详细论述。最后,详细介绍了功能成品率的分析模型。     

集成电路功能成品率模拟与设计方法

本文基于在缺陷空间分布和粒径分布的模型，研究并讨论了计算集成电路（ＩＣ）功能成品率的理论和模拟ＩＣ功能成品率的方法．为了验证所研究方法和模型的正确性，对测试图样和实际ＩＣ的功能成品率进行模拟，并分析了影响功能成品率的几个因素，得到了有益的结果．     

功能成品率估算的缺陷特征参数提取方法

基于微电子测试双桥结构,本文给出了缺陷特征参数提取方法.这些特征参数包含了缺陷在硅片上的空间分布和粒径(直径)分布,它们对集成电路功能成品率仿真是重要的.     

硅片缺陷粒径分布的分形特征及动力学模型

本文研究硅片上与光刻工艺相关的尘粒的粒径分布，分析缺陷粒径分布的分形特征，利用缺陷粒径的分布函数得到缺陷粒径体系的分维数，建立缺陷粒径分布的分形模型，同时给出此模型所得参数的物理意义。最后，本文对缺陷粒径变化过程给出了新的动力学模型，并对此进行分析和讨论。揭示光刻缺陷的粒径分布及其动力学成因，为集成电路可制造性设计及功能成品率的精细表征开辟了一条新径。     

VLSI成品率统计中的缺陷成团效应及统计参数与面积的关系

本文以负二项分布为基础,在对两个实测统计结果进行分析的基础上,给出了VLSI成品率与缺陷分布统计中有关成团因子与芯片面积关系的模型.在模型的推导中考虑了由于缺陷的成团聚集效应引起的区域之间缺陷分布的相关性这一内在因素.模型与本文给出的两个实测统计结果的一致性很好.     

VLSI容错设计研究进展(1)——缺陷的分布模型及容错设计的关键技术

随着芯片面积的增加及电路复杂性的增强，芯片的成品率逐渐下降，为了保证合理的成品率，人们将容错技术结合入了集成电路。文中首先概述了缺陷及其分布，然后概述了容错技术，并详细地叙述了动态容错技术中的两个关键问题：故障诊断及冗余单元的分配问题。     

SPC中的缺陷成团控制图

控制图是 SPC中的基本工具。其中广泛用于传统工业的缺陷数控制图要求被分析的数据 (每批样本中的缺陷数 )遵循泊松分布。但是 ,在半导体器件和微电路生产中 ,“缺陷”呈现明显的“成团”现象。在这种情况下 ,需要采用描述缺陷成团现象的负二项分布和黎曼分布构造控制图。如果采用常规缺陷数控制图分析缺陷成团数据 ,有可能对工艺线的受控状态作出错误的判断     

一种超深亚微米下IC光刻透射成像的快速算法

光学邻近效应校正（OPC）是下一代集成电路设计和生产的重要工具。但是在OPC中，为了寻找合适的掩模补偿图形，必须迭代计算大量的空间稀疏分布的试探点成像。在这里提出了一种基于卷积核的快速稀疏空间光强的光刻仿真计算方法。一个双线性光学系统分解成为一组空间域卷积核。并通过对版图的空间域卷积来计算空间光强。与采用Hopkins公式的SPLAT相比。这种方法能快速地计算空间光强。尤其对于大面积计算显得更为有效。     

二维斜周期阵列的分数泰伯效应

对振幅型二维斜周期阵列分数泰伯效应的研究,可以为设计和制作新型阵列发生器提供必要的理论依据。通过坐标的旋转与倾斜描述二维振幅型斜周期阵列,根据菲涅耳变换公式在理论上研究这类斜周期阵列的自成像效应,并进一步讨论了分数泰伯距离处像场的振幅分布与相位分布,给出了具体的相位计算公式。以60°斜交周期菱形阵列为例,模拟计算了它们在各自分数泰伯距离处的像,模拟计算的结果与数学公式推导的结果一致。并简单讨论了利用这种周期结构,设计和制作新型阵列发生器的可行性。另外,还对二维斜周期菱形阵列与正交周期方形阵列在压缩比例和光斑模式等特性上进行了比较分析。     

改进的一维分形模型在海面电磁散射中的应用

本文中提出了一种改进的一维分形海面模型,其表面谱在空间波数小于基波波数及大于基波波数时分别满足正幂率关系和负幂率关系,在不同风速时分形模型的表面谱和PM谱吻合较好.在满足Kirchhoff近似条件下推导了改进分形模型的散射系数及散射强度系数的计算公式并进行了数值计算,比较了改进分形海面模型和经典分形海面模型下散射强度系数角分布并讨论了它们随入射频率和海上风速的变化.     

The effect of the number of defect mechanisms on fault clusteringand its detection using yield model parameters

The superposition principle is used to analyze faults of different mechanisms. The sum of the individual cluster coefficients of each mechanism is approximately equal to the cluster coefficient for all mechanisms combined. This technique is used on defect density test structures as well as bit failures from SRAM chips. A regression analysis of empirical data is used to demonstrate this concept for the defect density test chips. The actual and, the model fault densities are compared and show excellent agreement. As a comparative analysis, a quadrant technique was used to compile a frequency distribution of electrical faults and a nonlinear least-squares technique is applied to the distribution to estimate the parameters in the gamma and Poisson distributions. These results are compared to the cluster parameters from the summation technique and the technique using moment estimates. All three estimates are in very good agreement. The application of this model to actual chip yields is shown not only to be more accurate but also to contain information about the relative number of fault generating mechanisms for the mask level of interest in the process     

Yield optimization of modular and redundant multimegabit RAMs: astudy of effectiveness of coding versus static redundancy using thecenter-satellite model

To determine the optimal redundancy organization for yield enhancement, redundant and modular memories are analyzed using the center-satellite model. The model suggests that the degree of redundancy for a memory module be determined according to its distance from the periphery of the wafer since the defect density increases as the periphery is neared. Analytical expressions are formulated for the yield of memory modules with extra rows and/or extra columns, coding, and coding with extra rows. Results from the analysis suggest that, for high levels of defect densities, coding can be more effective than simple extra rows and columns. For high levels of defect densities, coding with extra rows is shown to offer even better yield. For low levels of defect densities, though, just extra rows and columns may be sufficient for a high yield. An optimal amount of redundancy can be found to achieve the highest possible yield using the model that considers precise cluster distributions on the wafer, defects in a cluster, and the radial variation of these defects     

The nature of defect patterns on integrated-circuit wafer maps

The history of IC-yield models dates from those based on the simple Poisson distribution to current models based on the families of compound and generalized Poisson distributions. The latter are more complex because the IC chips have grown larger in area and circuit density, thereby unveiling the clustering (aggregation) properties of defects on wafers. These clustering properties are reflected by the parameters of the distributions on which the existing yield models are based. The possibility of any statistical distribution providing an exact representation of some actual population is very small. It is important, though, that the parameters of alternative statistical distributions describing some actual population should have some physical meaning. This paper considers 3 distributions used to model empirical defect distributions in IC manufacturing. The applicability of these distributions depends strongly on the area of the chips fabricated on a wafer. The authors discuss the cases where a study of the parameters alone might not provide conclusive evidence about the spatial properties of defect patterns on IC-wafer maps. They propose some measures to explain defect clustering: variance/mean ratio, turning point, mean crowding, and patchiness. Due to the complementary nature of these measures, no measure, by itself, can provide sufficient information about defect patterns or complete details of the differences between several patterns. It is therefore instructive to analyze defect patterns by as many measures as feasible     

Defect cluster analysis for wafer-scale integration

A methodology for characterizing spatial defect distributions is presented. A correlation function approach providing spatial information not measurable with classical methods such as yield-versus-area curves is described. This additional information includes the spatial extent of defect clustering, the strength of clustering, and uncertainty in clustering magnitude. The correlation function methods are applicable to experimentally determined defect maps or to simulation results based on different assumptions concerning the spatial distribution of defects. It is also shown that the approach is useful in predicting yield for redundant circuit configurations when experimental data pertaining to the spatial distribution of defects are available. This type of yield prediction capability is important for judging the feasibility of various redundancy implementations, including wafer scale integration     

IC缺陷轮廓的分形插值模型

现用于集成电路(IC)成品率预报及故障分析的缺陷模型均是用圆或正方形来代替真实缺陷的复杂轮廓进行近似建模的,从而在模型中引入了很大的误差。本文利用分形插值的思想直接对真实缺陷的轮廓进行模拟,从而提出了一种新的缺陷轮廓表征模型。实验结果表明:与传统的最大圆模型、最小圆模型及椭圆模型相比,新模型的建模精度有了很大的提高。     

二维改进分形海面模型及海谱分析

针对分形海面模型的功率谱在空间波数小于基波波数时不能满足正幂率的问题,提出了一种统计模型和归一化带限Weierstrass分形模型相结合的二维海面模型,确定了方向海谱的闭式解,得到了表面功率谱和方向分布函数,并且和有关文献的数据进行了对比,对分形维数、频率幅度尺度因子、风速和风向等参量对海面轮廓的影响做了进一步分析。从仿真结果可知:表面功率谱和PM谱、JONSWAP谱、文圣常谱和南海的实测数据都拟合的很好,方向分布规律和Mitsuyasu方向函数相似,海面形状具有大尺度涌浪和小尺度张力波的特性,并且统计模型和分形模型的性质在改进模型中依然适用,验证了模型的有效性。     

Defect clustering viewed through generalized Poisson distribution

It is shown that generalized double Poisson distributions provide a good basis for yield models when moderate spatial heterogeneity exists between chips of larger sizes, or when defects are almost randomly distributed. The model includes the average number and size of clusters as its parameters. On being tested with simulated as well as actual wafer particle maps, the model gave a significance level >0.95 in most of the cases. This model is simple and facilitates direct implementation of multilevel or hierarchical redundancy in regular VLSI/WSI designs. The strength of the proposed model lies in its simplicity and its ability to provide a physical explanation of the clustering process through its parameters. The model reflects the effects of the competition which can occur among defects in a cluster during wafer processing. Comparisons of yield predictions by various models for wafer maps with different spatial properties are reported     

Quantitative characterization of electron micrograph image usingfractal feature

In this investigation, texture analysis was carried out on electron micrograph images. Fractal dimensions and spatial grey level co-occurrence matrices statistics were estimated on each homogeneous region of interest, The fractal model has the advantages that the fractal dimension correlates to the roughness of the surface and is stable over transformations of scale and linear transforms of intensity. It can be calculated using three different methods. The first method estimates fractal dimension based on the average intensity difference of pixel pairs. In the second method, fractal dimension is determined from the Fourier transformed domain. Finally, fractal dimension can be estimated using reticular cell counting approach. Moreover, automatic image segmentation was performed using fractal dimensions, spatial grey level co-occurrence matrices statistics, and grey level thresholding. Each image was segmented into a number of regions corresponding to distinctly different morphologies: heterochromatin, euchromatin, and background. Fractal dimensions and spatial grey level co-occurrence matrices statistics were found to be able to characterize and segment electron micrograph images