Quantitative Evaluation Method for Etch Sidewall Profile of Through‐Silicon Vias (TSVs)

Through‐silicon via (TSV) technology provides much of the benefits seen in advanced packaging, such as threedimensional integrated circuits and 3D packaging, with shorter interconnection paths for homo‐ and heterogeneous device integration. In TSV, a destructive cross‐sectional analysis of an image from a scanning electron microscope is the most frequently used method for quality control purposes. We propose a quantitative evaluation method for TSV etch profiles whereby we consider sidewall angle, curvature profile, undercut, and scallop. A weighted sum of the four evaluated parameters, nominally total score (TS), is suggested for the numerical evaluation of an individual TSV profile. Uniformity, defined by the ratio of the standard deviation and average of the parameters that comprise TS, is suggested for the evaluation of wafer‐to‐wafer variation in volume manufacturing.     

基于ANMF和非线性映射距离扩展目标检测

针对距离扩展目标的检测问题,提出一种自适应归一化匹配滤波（ANMF）、非线性映射和高阶互相关积累（HOCC）相结合的目标检测方法。首先将距离像按慢时间进行脉冲维划分,得到若干脉冲子区间,再对每个脉冲子区间进行自适应归一化匹配滤波,然后利用非线性函数对滤波的输出进行非线性映射处理,最后将非线性映射的输出进行高阶互相关积累,从而获得检测统计量。仿真实验结果表明,在检测概率为80％时,所述方法比传统 ANMF 方法所需的信杂比低1 dB 左右,性能较为优越。     

一类环长至少为10的准循环LDPC码

为扩展性能优良、易于工程实现的LDPC码的构造方法,提出了一类环长至少为10的准循环低密度奇偶校验(quasi-cyclic low-density parity-check, QC-LDPC)码的构造方法。该方法首先基于基矩阵和 准则[11]构造出环长至少为10的校验矩阵;然后,利用掩蔽矩阵对得到的校验矩阵进行变换;最终,构造出满秩的准循环LDPC码。理论分析和仿真结果表明,该类QC-LDPC码字构造灵活,在AWGN信道下具有优异的性能。     

铜柱凸块生产关键工艺技术研究

讨论了铜柱凸块生产工艺中籽晶层厚度和电镀电流密度等关键制程因素对铜柱凸块共面性、晶圆应力、凸块剖面结构和电镀效率等方面的影响.研究结果表明增加电镀籽晶层厚度可以提高凸块共面性;在相同电镀电流密度下,籽晶层越厚,晶圆应力越大;相同的籽晶层厚度下,随着电镀电流密度增加,晶圆应力增加,但增加速率逐渐变慢;低电流密度下铜柱凸块顶部形成盘碟形状的剖面结构,而高电流密度容易使铜柱顶部形成圆拱剖面结构;采用阶梯电镀速率电镀方法与均一慢电镀速率电镀出的铜柱凸块共面性一致,而采用阶梯电镀法既能够提高电镀效率又可以得到较好的铜柱顶部盘碟形剖面结构.     

K波段宽带螺旋天线设计

从理论上分析了螺旋天线的设计原理,利用阿基米德螺旋天线实现了一款K波段的高频宽带螺旋天线,使高频天线拥有更轻的质量,更低的剖面及更好的圆极化性。最后通过仿真软件CST设计了一款带宽覆盖18.0~26.5GHz的阿基米德螺旋天线,涵盖了整个K波段。结果表明,该天线在整个频段电压驻波比<2,能很好的满足天线收发要求。     

An analytical depth resolution function for the MRI model

The mixing roughness information depth model is frequently used for the quantification of sputter depth profiles. In general, the solution of the convolution integral for any kind of in‐depth distributions is achieved by numerical methods. For a thin delta layer, an analytical depth resolution function is presented, which enables a simple and user‐friendly quantification of measured delta layer profiles in AES, XPS and SIMS. Copyright © 2013 John Wiley & Sons, Ltd.     

Capillary electrophoretic separation of serum proteins of workers occupationally exposed to heavy metals

Metallurgy processes are associated with many hazardous and toxic factors, including heavy metals. Exposure to heavy metals can cause damage to different organs, which can be observed through variation in the concentration of proteins in serum. The aim of this study was to evaluate the changes in a serum protein profile of copper smelters exposed to As, Cd and Pb ions, and xenobiotics present in tobacco smoke. A 2.3-fold higher Pb concentration in the blood and a 2.8-fold greater As concentration have been observed in the urine of non-smoking smelters compared to a control group. In the blood of smoking smelters, Cd concentration was 2-fold higher than in non-smoking ones. Serum proteins were separated by capillary electrophoresis, and in the group of non-smoking smelters, a higher amount of α₁-globulins was observed. In the group of smoking smelters, fewer α₁-globulins were noted. Furthermore, a greater amount of α₂-globulins in the serum of smoking and non-smoking workers in relation to the control group was revealed. A positive correlation between the concentration of Cd in the blood and the content of a fraction containing α₁- and α₂-globulins was revealed. Urine Cd concentration was found to be negatively associated with the α₁- and α₂-globulins fraction. Observed abnormalities in the proteins profiles of smelters can be important markers when assessing exposure to heavy metals and in the early diagnosis of diseases caused by them.     

Limit distribution of the coefficients of polynomials with only unit roots

We consider sequences of random variables whose probability generating functions have only roots on the unit circle, which has only been sporadically studied in the literature. We show that the random variables are asymptotically normally distributed if and only if the fourth central and normalized (by the standard deviation) moment tends to 3, in contrast to the common scenario for polynomials with only real roots for which a central limit theorem holds if and only if the variance is unbounded. We also derive a representation theorem for all possible limit laws and apply our results to many concrete examples in the literature, ranging from combinatorial structures to numerical analysis, and from probability to analysis of algorithms. © 2013 Wiley Periodicals, Inc. Random Struct. Alg., 46,707–738, 2015     

矩阵方程AX=B的中心对称定秩解及其最佳逼近

本文研究了矩阵方程AX=B的中心对称解.利用矩阵对的广义奇异值分解和广义逆矩阵,获得了该方程有中心对称解的充要条件以及有解时,最大秩解、最小秩解的一般表达式,并讨论了中心对称最小秩解集合中与给定矩阵的最佳逼近解.     

Investigation of block depth distribution in PS‐b‐PMMA block copolymer using ultra‐low‐energy cesium sputtering in ToF‐SIMS

Directed self‐assembly of block copolymers (BCPs) is a promising candidate for next generation nanolithography. In order to validate a given pattern, the lateral and in‐depth distributions of the blocks should be well characterized; for the latter, time‐of‐flight (ToF) SIMS is a particularly well‐adapted technique. Here, we use an ION‐TOF ToF‐SIMS V in negative mode to provide qualitative information on the in‐depth organization of polystyrene‐b‐polymethylmethacrylate (PS‐b‐PMMA) BCP thin films. Using low‐energy Cs⁺ sputtering and Bi₃⁺ as the analysis ions, PS and PMMA homopolymer films are first analyzed in order to identify the characteristic secondary ions for each block. PS‐b‐PMMA BCPs are then characterized showing that self‐assembled nanodomains are clearly observed after annealing. We also demonstrate that the ToF‐SIMS technique is able to distinguish between the different morphologies of BCP investigated in this work (lamellae, spheres or cylinders). ToF‐SIMS characterization on BCP is in good agreement with XPS analysis performed on the same samples. Copyright © 2013 John Wiley & Sons, Ltd.