Detection and classification of defect patterns on semiconductor wafers

The detection of process problems and parameter drift at an early stage is crucial to successful semiconductor manufacture. The defect patterns on the wafer can act as an important source of information for quality engineers allowing them to isolate production problems. Traditionally, defect recognition is performed by quality engineers using a scanning electron microscope. This manual approach is not only expensive and time consuming but also it leads to high misidentification levels. In this paper, an automatic approach consisting of a spatial filter, a classification module and an estimation module is proposed to validate both real and simulated data. Experimental results show that three types of typical defect patterns: (i) a linear scratch; (ii) a circular ring; and (iii) an elliptical zone can be successfully extracted and classified. A Gaussian EM algorithm is used to estimate the elliptic and linear patterns, and a spherical-shell algorithm is used to estimate ring patterns. Furthermore, both convex and nonconvex defect patterns can be simultaneously recognized via a hybrid clustering method. The proposed method has the potential to be applied to other industries.     

Robust position control of DC servomechanism with output measurement noise

This note presents a systematic robust control method for DC servomechanism based on the sliding mode technique. The noise in the measured position is considered. The proposed approach guaranteed system robustness against parameter variations and external disturbances. The common requirement of an integral function in the formulation of sliding surface is eliminated. The position tracking error dynamics in the sliding mode is assigned. Several practical techniques for implementing the control scheme are provided as well.     

An automatic coefficient design methodology for high-order bandpass sigma-delta modulator with single-stage structure

An automatic coefficient design method for synthesis of bandpass sigma-delta modulators (BPSDMs) is presented in this brief. Single-stage BPSDM structures, cascade-of-resonator with distributed feedback, cascade-of-resonator with distributed feedforward, and a new structure with lower coefficient spread, are all used to fit the synthesized coefficients. The automatic coefficient design method is realized in an easy-to-use computer program. Even for inexperienced designers, reliable and high-tolerance BPSDM coefficients for various applications can be automatically and efficiently generated. The methodology covers many design concerns including BPSDM coefficient tolerance for circuit component mismatch, design tradeoffs among in-band noise suppression, oversampling ratio, modulator order and quantizer bit number. Finally, design examples with orders of 6 and 8, and quantizer bit number of 1-bit and 3-bit, respectively, are used for the verification of the proposed automatic coefficient design method.     

Triple-frequency planar monopole antenna for side-feed communication device on GSM/DCS/PCS operation

A novel side-feed planar monopole antenna capable of triple-frequency operation at about 900, 1800 and 1900 MHz is presented. The planar monopole antenna occupies a small area of 6/spl times/31 mm, and is easily made using thin copper. The planar monopole antenna can be side-fed and mounted perpendicularly to the main circuit board of a communication device so that it offers a novel design with a free degree of feed point so as to save device space, resulting in a low profile to the system ground plane. In addition, the obtained impedance bandwidths of the proposed antenna at about 900, 1800 and 1900 MHz can cover the GSM (890-960 MHz), DCS (1710-1880 MHz) and PCS (1850-1990 MHz) bands.     

基于数据仓库的销售数据可视化分析系统

为了辅助销售管理者充分利用已有的历史销售数据,快速直观地捕获敏感数据,及时准确地把握市场行情,研究了以数据仓库为分析平台,根据销售数据具有的地理特征,结合Google提供的Google Maps API（Application Program Interface）,将OLAP（Online Analytical Processing）的分析操作映射到地图具有的交互操作上的可视化分析系统。并基于实际案例着重设计并优化了数据仓库架构,为系统应用开发奠定了良好的基础。实践证明,系统有效提高了销售管理部门的统筹决策的效率及能力,为企业创造了更大的经济效益。     

入侵防御系统可信通信协议的设计与实现

入侵防御系统主要基于入侵检测系统和防火墙之间的联动,而它们各自能识别和维护的数据格式往往是不同的。此外,这些敏感数据通常是在开放的网络环境中传输的,面临各种安全威胁。为此,引入可信通信的概念,设计并实现了基于XML（eXtensible Markup Language）的可信通信协议。与同类工作相比,该协议可实现异构操作环境下入侵检测系统与防火墙之间的安全数据传输,并可进一步扩展支持各种网络安全产品和网络管理设备,对于实现这些设备之间的数据融合,检测复杂的分布式网络攻击具有一定的参考价值。     

联吡啶钌配合物对末端炔烃的催化

以6,6＇-二甲基-2,2＇-联吡啶为配体合成了二水合氯化顺一二氯·二（6,6＇-二甲基-2,2＇联吡啶）合钌（Ⅲ）配合物,进一步用三氟甲基磺酸银脱氯得到三（三氟甲基）磺酸顺一二水·二（6,6＇-二甲基-2,2＇联吡啶）合钌（Ⅲ）配合物．研究了后者对1-己炔、苯乙炔和丙炔酸乙酯环三聚反应的催化作用．实验结果显示环三聚产物具有区域选择性：产物只有1,2,4一三取代苯与1,3,5-三取代苯两种同分异构体,且主要为1,2,4一三取代苯．催化机理研究表明,三（三氟甲基）磺酸顺一二水·二（6,6＇-二甲基-2,2＇联吡啶）合钌（Ⅲ）中的两个水分子配体首先被两分子炔烃取代生成π-炔基配合物,然后通过氧化偶联反应得到钌杂环戊二烯配合物;第三个炔烃分子经由插入反应或双烯加成反应生成钌杂环庚三烯或7一钌杂双环[2．2．1]-2,5-庚二烯中间体,随后发生还原消除反应得到三取代苯．     

A module‐integrated isolated solar micro‐inverter without electrolytic capacitors

This paper presents a module‐integrated isolated solar micro‐inverter. The studied grid‐tied micro‐inverters can individually extract the maximum solar power from each photovoltaic (PV) panel and transfer to the AC utility system. A harmonic suppression technique is used to reduce the DC‐bus capacitance. Electrolytic capacitors are not needed in the studied solar micro‐inverter. High conversion efficiency, high maximum power point tracking accuracy and long lifespan can be achieved. The operation principles and design considerations of the studied PV inverter are analyzed and discussed. A laboratory prototype is implemented and tested to verify its feasibility. Copyright © 2012 John Wiley & Sons, Ltd.