In Situ and Real-Time Monitoring of Plasma Process Chamber Component Qualities and Predictive Controlling of Wafer Yields

Plasma interactions with chamber components and wafers in semiconductor manufacturing processes have been monitored with a fault detection technique. Not only can this diagnostic technique monitor the wafer and process chamber components qualities, but it also has potential in saving tremendous amounts of manufacturing costs and improving equipment productivity. We have discovered that the abnormality in certain plasma processing parameters detected in the early stages of a manufacturing line can have a strong correlation with the product yield. Possible reasons for the observed correlations are explained     

Temperature Control and In Situ Fault Detection of Wafer Warpage

Warped wafers can affect device performance, reliability, and linewidth control in various processing steps. We propose in this paper an in situ fault detection technique for wafer warpage in lithography. The use of advanced process control results in very small temperature disturbance making it suitable for industrial implementation     

In Situ Endpoint Detection by Acoustic Emissions in Chemical–Mechanical Polishing of Metal Overlay

Chemical-mechanical polishing (CMP) has been recognized indispensable to achieve the global planarity in removal of metal overlay across the wafer, when the number of interconnecting metal layers and the size of wafer increase and the line rule reduces to nano scale. CMP has to stop at the endpoint when the overlay metal has been removed, or dishing will occur which affects the subsequent lithography in IC manufacturing. An effective in situ endpoint monitoring method essentially improves the yield rate and throughput of CMP. One notices the coefficient of friction between the pad and dielectric layer is distinguishably lower than the one between the pad and the copper overlay, based on that an endpoint monitoring method using acoustic emissions during the chemical mechanical polishing is feasible. The proposed method is tested in the experiment, and the comparison with the previous thermal monitoring technique shows consistent results.     

In Situ Acoustic Temperature Measurement During Variable-Frequency Microwave Curing

Variable-frequency microwave (VFM) curing can perform the same processing steps as conventional thermal processing in minutes, without compromising intrinsic material properties. With increasing demand for novel dielectrics, there is a corresponding demand for new processing techniques that lead to comparable or better properties than conventional methods. VFM processing can be a viable alternative to conventional thermal techniques. However, current limitations include a lack of reliable temperature measuring techniques. This research focuses on developing a reliable temperature measuring system using acoustic techniques to monitor low-k polymer dielectrics cured on silicon wafers in a VFM furnace. The acoustic sensor exhibits the capability to measure temperatures from 20degC to 300degC with an attainable accuracy of plusmn2 degrees.     

Full Field Temperature Measurement of Specular Wafers During Rapid Thermal Processing

Many of the processes involved in the creation of semiconductor devices involve high-temperature processing of silicon wafers. The benefits of reduced thermal budget and faster cycle time make rapid thermal processing (RTP) a possible key technology for semiconductor manufacturing. However, the problem of nonuniform wafer temperature has prevented it from further spread among the industry. The first step in developing controls to maintain a uniform wafer temperature is accurate temperature measurement during processing. In this paper, a system was developed to exploit the specular reflectivity of silicon wafers and obtain a measurement of the wafer temperature profile. The spectral reflectivity is determined by measuring the intensity of an incident beam and the beam reflected from the wafer surface. With this measured reflectivity value the spectral-directional wafer emissivity was determined using Kirchhoff's law. The obtained emissivity then was used to calculate the wafer temperature profile from an image obtained with an infrared camera. An experimental study of the transmittance of an undoped silicon calibration wafer at an elevated temperature is also discussed     

一种面向性质的实时系统测试方法

尽管Statecharts在反应式实时系统建模领域获得了广泛应用,基于Statecharts开发的实时软件的测试仍然十分困难.由于引入了时间维,待测系统的行为空间变得非常庞大,使得难以对其进行全面深入测试.本文提出了一种面向性质的实时系统测试方法.首先对UML Statecharts作适当实时扩展,使得扩展后能描述non-trivial时间约束;然后用一种受限实时逻辑描述待测系统的功能特性;在此基础上根据待测性质从系统模型生成有针对性的测试序列.实验表明,在相同测试深度下,面向性质测试比非面向性质测试需要少得多的测试序列.     

In Situ Interferometric Monitoring of Fiber Insertion in Fiber Connector Components

We present an interferometric setup for in situ monitoring of fiber tip positions when inserting optical fibers for fixation in fiber connector components. It ensures an accurate fiber tip position at the fiber connector's front facet and across the fiber array in cases where postinsertion polishing is not possible. We demonstrate our technique by populating a plastic fiber connector for optical interconnect applications, and compare the fiber tip position measured in situ using our setup with the position measured off-line using a commercial white light interferometer, showing a deviation smaller than 5%.      

An Integrated Approach to Thermal Management in High-Level Synthesis

Thermal effects are becoming an important factor in the design of integrated circuits due to the adverse impact of temperature on performance, reliability, leakage, and chip packaging costs. Making all phases of the design flow aware of this physical phenomenon helps in reaching faster design closure. In this paper, we present an integrated approach to thermal management in architectural synthesis. Our synthesis flow combines temperature-aware scheduling and binding based on feedback from thermal simulation. We show that our flow is effective in preventing hotspot formation and creating an even thermal profile of the resources. Our integrated thermal management technique on average reduces the peak temperature of the resources by 7.34 degC when compared to a thermal unaware flow without increasing the number of resources across our set of benchmarks     

In Situ Characterization of the Degradation of PLGA Microspheres in Hyaluronic Acid Hydrogels by Optical Coherence Tomography

The polymeric implant material poly(lactide-co-glycolide) (PLGA) degrades by a process of bulk degradation, which allows it to be used for the controlled release of therapeutic molecules from implants and microspheres. The temporal characterization of PLGA microsphere degradation has been limited by the need to destructively monitor the samples at each time point. In this study, a noninvasive imaging technology, optical coherence tomography (OCT), was utilized to characterize the in situ degradation of PLGA microspheres suspended within photo-crosslinked hyaluronic acid (HA) hydrogels. Microspheres with differing degradation rates were loaded with bovine serum albumin (BSA) as a marker protein, and temporal release of protein was correlated with morphological changes observed during 3-D OCT imaging. As proof-of-principle, a microsphere-loaded hydrogel scaffold was implanted in a modified rat calvarial critical size defect model and imaged using OCT. This animal model presents the opportunity to monitor microsphere degradation over time in living animals.      

基于LabWindows/CVI的一种仪器控制的实现方法

本文研究了一种基于LabWindows/CVI环境下一种仪器控制的方法,利用开发环境自带的RS-232串口函数库,同时根据仪器的命令集格式编写相应的仪器控制程序,完成对仪器的控制.采用该方法实现的仪器控制技术摆脱了对仪器自带控制软件的依赖,具有较强的通用性和灵活性,更适合于不同场合的实际应用.     

IMM-UKF在光电经纬仪实时数据处理中的应用

飞行试验中,异常值是影响光电经纬仪激光测距精度的主要问题。能否准确地剔除异常值,成为试验结论是否正确的首要条件。通过分析无迹卡尔曼滤波UKF和交互多模型IMM的原理及数学模型,提出了可应用于光电经纬仪实时数据处理的改进算法———交互多模型的无迹卡尔曼滤波算法(IMM-UKF),在此基础上给出了算法数学模型,最后通过飞行试验验证了该算法的工程实用性。试验结果表明,该算法有效去除了激光距离中的异常值,提高了估计精度及算法稳定度。     

An Integrated Approach to Digital Control of AC Motor Drives

The paper describes a high-performance microcomputer-based controller for inverter-fed ac motor drives. Both the implementation of high-level drive control policies and on-line computation of three-phase switching patterns for control of the inverter output frequency and voltage, are carried out by a single ?P. The selection of a pulsewidth modulation (PWM) strategy with limited processing requirements, has made the integration of these features possible without devising a multiprocessor architecture, or relying upon dedicated hardware to support specific functions. Peculiar facilities, like on-line reconfigurability of control parameters, real-time tracing of system behavior and diagnostics, have also been implemented to enhance the overall controller performance and flexibility. The validity of the integrated solution has been thoroughly verified by extensive experimental tests carried out with a prototype system composed of an 8085-based microcomputer, a 30-kVA three-phase transistor inverter, and a 20-kW induction motor.     

Silicon–Carbon Stressors With High Substitutional Carbon Concentration and In Situ Doping Formed in Source/Drain Extensions of n-Channel Transistors

We report the first demonstration of n-channel field-effect transistors (N-FETs) with in situ phosphorus-doped silicon-carbon (SiCP) stressors incorporated in the source/drain extension (SDE) regions. A novel process which formed recessed SDE regions followed by selective epitaxy of SiCP was adopted. High in situ doping contributes to low series resistance to channel resistance ratio and is important for reaping the benefits of strain. Substitutional carbon concentration was varied, showing enhanced drive current with increased for comparable off-state leakage, series resistance, and control of short-channel effects. A record high carbon substitutional concentration of 2.1% was achieved. Use of heavily doped silicon-carbon stressor with large lattice mismatch with respect to Si and placed in close proximity to the channel region in the SDE regions is expected to be important for strain engineering in nanoscale N-FETs.     

机载大斜视SAR的运动补偿方法

对机载大斜视的合成孔径雷达成像因速度变化引起的运动补偿方面的问题展开了研究 ,提出了大斜视角条件下运动补偿的方法 ,对其分别进行一次和二次相位补偿 ,并在进行方位压缩时考虑三次相位 ,其结果能较好地实现运动补偿。同时对补偿性能也作了分析 ,对基于运动参数估计的窄波束宽幅SAR成像算法进行了改进 ,增加一次和二次相位补偿的步骤 ,成为适用于机载大斜视SAR的成像算法     

一种提高扩散氧化炉温度控制精度的方法

针对半导体制造流程中氧化、扩散、退火炉的Profile温度控制方法存在温度过冲大的问题,提出了Profile控制+前馈方式控制管内温度的新方法.将该方法应用于Thermco 9000扩散炉,使温度过冲由5℃左右减小到0.5℃以下,且恒温时间从25 min减小到20 min.     

The Evolving Face of Ethics in Technical and Professional Communication: Challenger to Columbia

Our view of ethics in professional and technical communication has evolved, paralleling developments throughout society. Earlier views on ethics and values have grown into a broad perspective of complex gradations with people at many levels affecting eventual practical outcomes. This newer perspective includes not only persons but social forces and organizations. The organizational culture of NASA, for example, was specifically identified by the Columbia Accident Investigation Board (CAIB) as one of the causes of faulty communication leading to a terribly tragic event. The Challenger investigations of 20 years earlier, on the other hand, focused primarily on physical events, secondarily on professional judgments, and only little on the social and cultural context of the disaster. We learn by failures but also by self-examination. As we see how ethics and values impact technical events, we understand that technological progress is ultimately a human endeavor in which reflection and judgment is as important as measurement and observation.     

氧化对 GaN 基LED透明电极接触特性的影响

研究了热退火对InGaN/GaN 多量子阱LED的Ni/Au-p-GaN欧姆接触的影响.发现在空气和 N2气氛中交替地进行热退火的过程中Ni/Au接触特性显示出可逆现象. Ni/Au-p-GaN接触的串联电阻在空气中随合金化时间逐渐减小,在随后的 N2 中的热退火后会使该串联电阻增加,但在空气中再次热退火能使接触特性得到恢复.同时对Ni/Au-p-GaN 接触在空气中合金化过程中的层反转的成因进行了讨论.     

An Approach to Integrating SIP in Converged Multimodal/Multimedia Communication Services

In this paper, we present an approach of integrating SIP (Session Initiation Protocol) in converged multimodal/multimedia communication services. An extensible VoIPTeleserver for VoIP in SIP environment is described. It is based on the concept of dialogue system and Web convergence that separates the channel dependent media resources from the application dependent service creation and hosting environment. It supports XML based service applications for multiple channels including voice, DTMF, IM and chat over IP. The loosely coupled open architecture in our approach is highly extensible. We describe the concept and structure of VoIPTeleServer used in our approach in detail, which interfaces to the VoIP world through SIP signaling and works as a broker between the VoIP SIP environment and MTIP to deliver converged communication services. A prototype of VoIPTeleServer was implemented, and services and applications based on SIP and MTIP convergence are constructed. Special attention is given to the adverse effect of delay, jitter and packet loss for voice portal services over IP. In particular, case studies of DTMF service in voice portal under adverse channel conditions are performed. The compounding effects of multiple channel impairments to DTMF in voice portal services over IP are characterized. The potential high error rate of the DTMF service indicates that the data redundancy method as proposed in RFC 2198 is needed for DTMF in order to achieve reliable voice portal services over IP.     

一种有效的BPSK/QPSK信号调制识别方法

根据不同调制信号相位差分的变化规律,文章提出了基于相位差分峰值幅度比较的BP SK/QPSK调制识别方法。仿真结果验证了调制识别方法的有效性。