微三维结构型腔的微细电火花加工

利用简单截面形状电极,建立在在分层制造思想上的电极等损耗微细电火花加工技术是实现微三维结构微细加工的有效手段。分析了该方法的工艺特点;研究了实现该技术的条件及电极损耗补偿策略。     

电火花加工中电极损耗自动测量及自动补偿

介绍了对电火花成形加工中产生的电极损耗进行自动测量及自动补偿的方法。运用这一方法能提高产品尺寸、形状精度。同时实现了自动连续无人化的加工，尤其适用于单电极多型腔的加工，保证各个型腔尺寸一致。     

LIGA和微细EDM技术制造不锈钢微结构的研究

通过LIGA技术与微细电火花技术相结合，可以在硬质合金、不锈钢等材料上加工出微结构，这一新的方法必将拓宽微细加工的能力和应用范围。利用LIGA技术制备线宽70μm、厚度达730μm的铜工具电极，采用微细电火花技术在不锈钢片上加工出线宽90μm、具有复杂形状的微结构。     

正极性电火花加工的损耗机理及其参数分析

本文基于场致发射电子对阳极表面材的料溅射能量分析,研究了引起正极性电火花加工时阳极材料的损耗机理,并给出了正极性加工时电极损耗率的理论极大值与极小值方程。设计并进行了不同工艺参数下紫铜电极和A3＃钢电极单孔电火花加工对比实验,实验表明：相同工艺参数下,紫铜电极比A3＃钢电极加工时的极间放电能量大,加工效率对比上前者是后者的极的75倍多,但电极材料的损耗率对比上,前者是后者的近10倍;不同工艺参数下,极间有效放电时间和放电能量越大,加工效率越高,相应的电极的损耗率也增加,但损耗率的增加程度要远小于加工效率的提高程度。     

微纳米薄膜的悬浮腐蚀法

介绍了一种腐蚀薄膜的研制方法及其装置.为制备带有各种金属引线及电极的大面积超薄悬浮薄膜(厚度:50～500nm、1～5μm;面积:3mm×2mm、10mm×5mm)提供了一种有效的方法.提高成品率30%,具有装置结构简单、支架体积小、质量轻、易于加工、操作方便、经济耐用、造型可根据器件需要加工设计等优点.     

负极性电火花加工时的电极损耗机理及积碳层的减损作用研究

本文基于场致发射理论,对负极性电火花加工时电极材料的损耗情况及极间做功能量进行了研究,设计并分别进行了不同工艺参数下紫铜电极和A3#钢电极单孔负极性电火花加工对比实验.实验研究结果表明:相同工艺参数下,紫铜电极比A3#钢电极加工时的极间放电能量大,加工效率高且电极材料的损耗率低:表面积碳层对紫铜电极材料有着良好的减损作用,而对A3#钢电极则作用甚微;且对紫铜电极而言,在保证有效消电离的情况下,极间有效放电时间比越高,加工效率越高,电极的损耗率越低,而相应的积碳层对电极材料的减损率则减小.     

电火花铣削钛合金电极损耗在线补偿研究

根据电火花铣削等损耗理论，对用电火花铣削钛合金的加工中电极损耗补偿作了分析阐述。并根据正交试验的数据对理论分析结果进行对比，同时给出了一定的结论和建议。     

一种集成式压电驱动微型电火花加工装置

首先概括了压电微驱动技术在电极直接驱动的微小型电火花加工装置中的应用现状。在此基础上，结合线电极电火花磨削技术，提出了一种压电驱动的、可实现多种形式的电极旋转和轴向进给的集成式电极直接驱动微小型电火花加工装置。介绍了该新型机构的原理并对其进行了初步的建模与有限元分析。该机构具有结构简单，可实现多种运动形式合成的特点，可应用于多种微驱动场合。     

基于氮化铝技术的表贴型微波封装

采用氮化铝多层布线技术,运用垂直过渡方式实现微波信号从基板底部到表面的信号传输,完成表贴式微波封装设计。在DC-18GHz内,该表贴互连反射损耗小于-15dB,插入损耗小于1.0dB。采用该技术封装了6～18GHz宽带放大器,封装尺寸为5mm×5mm×1.2mm,频带内反射损耗小于-10dB,增益15dB,平坦度小于1dB;另外还封装C波段5W功率放大器,封装尺寸为8mm×8mm×1.2mm,带内增益大于25dB,反射损耗小于-10dB,饱和输出功率37dBm,效率35%。采用技术的表面贴装放大器性能上能够满足微波通信、雷达应用,可用回流焊安装,适合规模生产。     

微凸起及微坑结构的放电加工基础性研究

机械零件表面形成微凸起及微坑结构在摩擦学、仿生制造等领域具有重要意义.微细电火花加工是一种重要的精密微细加工技术,已经成为微三维实体制造的有效手段之一.通过选用合适的切割轨迹和电参数,能以电火花线切割微精加工多种形状的微凸起电极,继而以电火花成形加工出微坑结构;或者直接用电火花线切割加工微凸起结构.分析了加工电参数对电极制备精度的影响及加工前后电极形状尺寸的变化,研究了所获微坑的几何参数及表面形貌特性,并对微凸起、微坑以及平面结构的摩擦磨损性能进行了初步分析比较.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.