Mass patterning of polysiloxane layers using spin coating and photolithography techniques

Polysiloxane (PSX) containing 2,2-dimethoxy-2-phenylacetophenone (DMPA) photoinitiator has been used as a photosensitive polymer. Thus, thin PSX films have been deposited by spin coating and patterned thanks to standard ultraviolet (UV) photolithography. The influences of the different technological parameters (PSX dilution, spin speed, UV exposure time) have been studied in so as to understand the polysiloxane deposition and cross-linking phenomena. Finally, the whole process has been optimised. Results evidence the realisation of high quality PSX patterns for the development of mass-fabricated ion sensitive layers in the field of chemical microsensors.     

Thick volume hologram for applications in microwave frequency band

Artificial dielectric technology is used in the realisation of the transverse modulation of refractive index to fabricate a thick volume hologram for microwave- and millimetre-wave applications. A prototype is fabricated accordingly and tested to verify the concept. This is believed to be the first time that a thick volume hologram is implemented for application in microwave and millimetre-wave frequency bands.     

Ion-beam etched multi-level resist technique for electroplating of submicron gold absorber patterns

A structuring process is developed which enables the fabrication of gold patterns by electroplating with a minimum linewidth of ? 0.3 μm. These patterns are used as mask patterns for X-ray lithography. They can be up to 1.6 μm thick. For this purpose, a resist pattern, which is generated by an electron beam, is transmitted to a multi-layer system by reactive ion-beam etching. The multi-layer system consists of a 2 μm thick polyimide layer, a 70 nm thick aluminum intermediate layer and a 30 nm thick gold passivation layer.With this process, X-ray masks with a polyimide membrane were produced and utilized for exposure to synchrotron radiation.     

Precise realisation of current mode integrator using current conveyor

The realisation of a differential input current mode integrator network using the second generation current conveyor (CC II) is proposed. Even with nonideal CC IIs, true differential input capability and precise compensation of the time constant tau can be obtained by suitable design. A minimum of passive RC components is needed; their interchanged connection yields alternate differentiator functions.<>     

Monolithic v.c.c.s. for high-frequency RC active filters

A monolithic voltage-controlled current source designed for the realisation of high-quality RC active filters at frequencies up to 1 MHz is described. The chip is fabricated using standard 741 technology with lateral p-n-p transistors, and requires no internal compensation for stabilisation.     

Gain-element transfer response control for octave-band feedforwardamplifiers

The development of software radio drives a requirement for octave-band linear amplifiers. Here, one linearisation technique, feedforward, is presented as an applicable architecture for this requirement. The realisation of this architecture requires octave-band operation from its sub-components. Two techniques are compared that facilitate this need within gain stages-linear compensation and direct RF feedback     

Characterization of spatial intrafield gate CD variability, its impact on circuit performance, and spatial mask-level correction

The authors present a comprehensive characterization method applied to the study of the state-of-the-art 18-/spl mu/m CMOS process. Statistical characterization of gate CD reveals a large spatial intrafield component, strongly dependent on the local layout patterns. The authors describe the statistical analysis of this data and demonstrate the need for such comprehensive characterization. They describe the experimental setup of the novel measurement-based characterization approach that is capable of capturing all the relevant CD variation patterns necessary for accurate circuit modeling and statistical design for increased performance and yield. Characterization is based upon an inexpensive electrically based measurement technique. A rigorous statistical analysis of the impact of intrafield variability on circuit performance is undertaken. They show that intrafield CD variation has a significant detrimental effect on the overall circuit performance that may be as high as 25%. Moreover, they demonstrate that the spatial component of gate CD variability, rather than the proximity-dependent component, is predominantly responsible for speed degradation. In order to reduce the degradation of circuit performance and yield, the authors propose a mask-level spatial gate CD correction algorithm to reduce the intrafield and overall variability and provide an analytical model to evaluate the effectiveness of correction for variance reduction. They believe that potentially significant benefits can be achieved through implementation of this compensation technique in the production environment.     

A novel CMOS exponential transconductor operating in weak inversion

A novel CMOS exponential transconductor which employs only three NMOS transistors operating in weak inversion, is presented. The main advantage of the proposed circuit is its wide range of exponential behaviour, which reaches up to five decades of current range, and above 10 μA to an input voltage range of 800 mV. The physical realisation is achieved in two forms: in the first one, the circuit is implemented with discrete MOS transistor arrays by CD4007 series; in the second one, the circuit is fully integrated in a 0.5 μm CMOS standard process. Simulated and experimental results of the proposed exponential transconductor are also presented.     

厚铜箔印制板尺寸稳定性研究

伴随着电源模块等大功率元器件的市场需求量不断加大,厚铜箔印制电路板的产量也不断增加,其对品质的要求也越来越严格。众所周知,厚铜箔印制电路板在其生产制作中产生的热膨胀系数量一直是影响其品质的重要因素,本文正是着眼于信息产业高科技、高精度的要求,通过对厚铜箔板的工艺流程、材料本身特点、设计三个因素来试验找出厚铜箔印制板系数补偿的重点考虑因素,同时对热膨胀系数量进行统计分析,从而保证厚铜板涨缩控制在范围之内,达到客户的要求。     

厚层抗蚀剂曝光模型及其参数测量

针对厚层抗蚀剂曝光过程中存在诸非线性因素的影响，更新Dill曝光参数的定义，建立了适合描述厚层抗蚀剂曝光过程的增强Dill模型．光刻过程模拟的准确性与曝光参数的测量精度有很大关系，为此，建立了实时曝光监测实验装置，测量了不同工艺条件、不同厚度抗蚀剂的曝光透过率曲线，并演绎计算出曝光参数随抗蚀剂厚度和工艺条件的变化规律．最后给出了采用增强Dill模型进行曝光过程的模拟和实验结果的分析．     

硅各向异性腐蚀中生成直角补偿结构的新方法

Detailed characteristics of three classical rectangular convex corner compensation structures on（100） silicon substrates have been investigated, and their common design steps are summarized.By combining the basic method of a silicon wet anisotropic etching process, a general method of generating compensation structures for a rectangular convex corner is put forward.This calls for the following two steps：define the topological field and fit some borderlines together into practical compensation patterns.The rules, which must be obeyed during this process, are summarized.By introducing this method, some novel compensation patterns for rectangular convex corner structures are created on both（100） and（110） substrates, and finally simulation results are given to prove this new method＇s validity and applicability.     

Design for good matching in multichannel low-noise amplifier for recording neuronal signals in modern neuroscience experiments

The paper reports on the design of a prototype 16-channel ASIC for readout of signals from live neuronal systems. Single channel comprises a low-noise amplifier and a low-frequency pass-band filter. The amplifier design optimised with respect to noise and power consumption is discussed. The design of a continuous-time high-pass filter with lower cut-off frequency as low as 20 Hz, which is suitable for realisation in a CMOS process, is presented. Special attention is paid to uniformity of analogue parameters in the multichannel IC. Channel matching is evaluated by Monte Carlo simulation. The design has been fabricated in a 0.7 μm CMOS process and measurements of basic parameters and characteristics have been performed for the prototypes. Good agreement between the simulation and measurements has been achieved for single channel parameters as well as for channel matching. The obtained results on channel matching are discussed with respect to design reliability and production yield.     

Complex cascade programming and associated computional errors

A technique is described which enables a pulsed transfer function with complex poles and zeros to be cascade-programmed. Owing to the finite wordlength of the computer, computational errors arise when the realisation is used to process information. These can be represented in the steady state by a set of spurious error sequences additively contaminating the output of an ideal realisation. The shaping filters relating these error sequences to simple roundoff errors are derived.     

光电自准直系统的建模方法研究

针对现有自准直模型包含系统信息量有限的不足,提出了一种基于厚透镜对光线变换的建模方法.以应用光学中厚透镜对光线变换的理论为基础,结合矢量运算和坐标系旋转方法建立了光电自准直系统数学模型.通过数值仿真,对模型中包含的平面镜的转角、透镜的厚度、焦距及表面曲率半径、光源和探测器位置等系统主要参数对光电自准直系统的成像影响进行了分析,并通过对像点几何中心的提取,分析了透镜成像畸变对光电自准直系统测量精度的影响.文章建立的模型,为系统参数的提取和优化、分析像点轨迹变化的影响因素以及自准直测量误差的分析和补偿提供了理论支持.     

Reduction of linear systems by canonical forms

A new companion-type realisation of a rational transfer function is introduced. This form is then used for obtaining a reduced-order model. It is possible, using this approach, to simultaneously match time moments, Markov parameters and to retain desired poles, thus combining the methods of partial realisation (Padé approximation) and aggregation.     

Computing the minimal polynomial by using Koenig's theorem

An algorithm is given to determine the transfer function or minimal realisation of a finite-dimensional linear time-invariant system from its Markov parameters or time moments. The method makes a direct computation of the minimal polynomial by using Koenig's theorem.     

空间光通信系统三波段滤光膜的研究

空间激光通信常采用干涉截止滤光膜对不同波段的光谱进行分光。着重介绍了近红外三波段光学滤光片的研究与制备。根据膜系设计理论,分别选择TiO2和SiO2作为高、低折射率材料,借助膜系设计软件设计优化了合理的膜系,实现了770～860nm及1530～1575nm光谱范围双波段的高透过和1615～1700nm波段的高反射。采用电子枪离子辅助沉积系统进行制备。优化工艺参数,通过调整补偿挡板使膜厚均匀性控制在3%以内。虽然制备膜层较厚,但经检测其光学性能、机械性能及耐环境能力均满足使用要求。用轮廓仪检测所制备膜层的面形,其峰谷值变化达到预期要求。     

Adaptive high-speed resonant robot

The use of the natural modes of oscillation for efficient performing of complex space motions of a robot with changeable parameters and dynamically interacting degrees of freedom is discussed. For the realisation of high-speed motions in these conditions under the limitation of control torques, it is necessary to identify at first, through on-line analysis of motions in the process of manipulation, the real parameters of natural modes. Then the control torques should be brought into correlation with natural motions by the adaptation of control in accordance with the findings of identification. As a result, the processes of identification, adaptation and control have to be optimised in accordance with the dynamics of robot oscillation. The formulated concept is demonstrated by research and development of an adaptive high-speed manipulator MARS-3 realised by the above mentioned principles for operating in cylindrical co-ordinates.     

Minimal realisation of a symmetric transfer function matrix using Markov parameters and moments

An algorithm for determining a minimal realisation from a symmetric transfer function matrix using a combination of Markov parameters and moments has been proposed. The procedure seems preferable for the problem of identification, when only a few Markov parameters are available.     

Characterizing pairwise contact patterns in human contact networks

We use a counting process representation of the pairwise contact process to analyze pairwise contact patterns. Studying two real-world traces, we find that the pairwise contact patterns have three characteristics. First, human contact patterns are influenced by daily and weekly cycles of activity. Second short time intervals with intensive contact event (bursts) are separated by long periods with few contact events. Third, the pairwise contact process exhibits long range dependence. We introduce a Markov modulated Poisson process (MMPP) as a flexible model for pairwise contact process exhibiting both regular structure and irregular bursts of activity. Using standard statistical techniques, we demonstrate that the proposed model is consistent with the empirical data. Our work has significant implication for mobility modeling and performance analysis in human contact networks.