Overview of Cu contamination during integration in a dual damascene architecture for sub-quarter micron technology

A detailed study of copper contaminating steps performed during integration of multilevel Cu metallisation in dual damascene architecture has been performed. Contamination at the wafer back and the bevel edge should make it difficult to use the same equipment for conventional technology and new copper based technology. Several barrier materials have been claimed as efficient against copper diffusion. However, during process integration, contamination issues will be faced before deposition of the barrier layers. Heavy contamination can occur either during Cu chemical mechanical polishing (CMP) or during dielectric etching and via opening on top of contacted copper lines. These residues, concentrated at the dielectric surface, could result in current leakage and shorts between interconnection lines. Several cleaning solutions to remove metal contamination are reviewed and their efficiencies are compared.     

光子晶体应用于在浓度检测上的模拟研究

采用平面波展开法数值计算了对二维光子晶体在TE和TM偏振态下的带隙进行了计算,给出了光子晶体中的禁带存在的理论依据,选择二维三角晶格光子晶体(GaAs)作为基底,在空气孔内填充浓度(质量百分浓度)为一定的待测溶液硫酸铜材料,通过计算得到了温度为298K情况下介电常数在71.917-62.530变化时,待测浓度的对应关系,并由此得到液体填充的光子晶体在不同偏振模式下光子禁带结构.结果表明,以硫酸铜的水溶液作为空气圆孔中的介质材料,当溶液质量百分浓度不同时光子带隙(PBG)发生变化。这对溶液浓度检测应用方面有一定的指导作用。     

5-DOF并串联机器人运动学分析及仿真

并联机器人强度刚度较高,但是工作空间较小;串联机器人工作空间较大,但强度刚度较小。混联机构因兼顾了并联和串联机构的优点而具有更加广泛的应用前景。文中介绍了一种新型五自由度并串联机器人来实现复杂曲面的加工。应用螺旋理论对其运动性质进行分析并计算了自由度。通过数值法推导了机器人的正解,运用解析法推导了机器人的反解。用SolidWorks构建了机器人的三维模型并导入到ADAMS中对其进行运动学仿真。仿真结果显示,该机器人能够实现复杂曲面的加工,可以为工业生产提供帮助。     

计算机病毒分析与防范的研究

当前,对信息领域构成极大威胁的是计算机病毒和木马。首先对计算机病毒和木马的生产、伪装等进行了详细的论述,其次研究了病毒的相关技术手段以及行为,进一步通过病毒例证详细分析、揭示了病毒产生的本质,最后针对病毒所采取的新的破坏手段加以预测和剖析,并提出了对预防病毒入侵的建议和解决方案。     

(Ba1-xSrx)(Zn1/3Nb2/3)O3固溶体系统第二相的研究

研究了(Ba1-xSrx)(Zn1/3Nb2/3)O3(BSZN)固溶体系统在烧结中生成的第二相,分析了第二相的分布、形貌、形成规律、机理以及对介电性能的影响。研究表明,系统的主晶相为BSZN,同时生成了大量的第二相——Ba5Nb4O15(、Ba5-xSrx)Nb4O15(x=0~5)、Ba2Nb2O7、BaNb2O6等。第二相的生成是由于ZnO的挥发造成的;烧结温度越高、烧结时间越长,ZnO的挥发越多,第二相的含量也越多。第二相的形貌大部分为长方形的板状,样品的表面部分或完全被第二相所覆盖,且有少量呈粒状散布于晶粒之间。第二相的生成会对系统介质损耗产生不利的影响。     

消除孤子互作用的综合研究

基于光脉冲在光纤中传输所遵从的NLS方程,采用对称傅里叶数值方法计算了不同因素引起的孤子互作用对其传输特性的影响。结果表明,孤子间隔、孤子间的相差以及两孤子的振幅比都是影响光孤子相互作用极其敏感的因素。本文同时引用实验数据计算了高阶色散对孤子互作用的影响,并针对各种因素提出了相应的解决方案,这对实际光孤子通信具有指导意义。     

表面活性剂对低渗透油藏渗吸的影响

采用不同类型的表面活性剂进行自发渗吸实验,并对表面活性剂改善岩石润湿性、降低界面张力的能力进行了分析。实验结果表明,阴离子型表面活性剂改善润湿性的能力好于其他类型的表面活性剂,且在岩心中的自发渗吸效果最好,这是由于阴离子型表面活性剂改善润湿性的机理为离子对形成机理,强于阳离子的吸附机理;接触角是决定渗吸能否发生的决定性因素,只有接触角小于70°时渗吸才能发生;界面张力影响渗吸速度和最终采出程度,对于渗透率为1 mD的岩心,最佳界面张力为10~(-1) mN/m。     

An Improved Particle Swarm Optimization Algorithm Based on Ensemble Technique

An improved particle swarm optimization （PSO） algorithm based on ensemble technique is presented. The algorithm combines some previous best positions （pbest） of the particles to get an ensemble position （Epbest）, which is used to replace the global best position （gbest）. It is compared with the standard PSO algorithm invented by Kennedy and Eberhart and some improved＇PSO algorithms based on three different benchmark functions. The simulation results show that the improved PSO based on ensemble technique can get better solutions than the standard PSO and some other improved algorithms under all test cases.     

Nonhomogeneos Boundary-Value Problem for Semilinear Hyperbolic Equation. Stability

We discuss the solvability of the nonhomogeneous boundary-value problem for the semilinear equation of the vibrating string x _tt (t, y) − Δx(t, y) + f(t, y, x(t, y)) = 0 in a bounded domain and a certain type of superlinear nonlinearity. To this end, we deduce new dual variational method. Next, we discuss the stability of solutions with respect to the boundary control and initial conditions.      

An analysis of the characteristics of the thermal boundary layer in power law fluid

This paper presents a theoretical analysis of the heat transfer for the boundary layer flow on a continuous moving surface in power law fluid. The expressions of the thermal boundary layer thickness with the different heat conductivity coefficients are obtained according to the theory of the dimensional analysis of fluid dynamics and heat transfer. And the numerical results of CFD agree well with the proposed expressions. The estimate formulas can be successfully applied to giving the thermal boundary layer thickness.