Design rules to minimize the effect of joule heating in Greek cross test structures

This paper presents work on the analysis of the effect of Joule heating on sheet resistivity measurements using Greek cross test structures. As part of this work, design rules have been derived to minimize the heating effect associated with currents forced during their measurement. To accomplish this, finite-element (FE) simulations were employed to identify the location of heat generation and cooling mechanisms in the structures. This identified that the temperature could be minimized by: firstly, decreasing cross arm length, and therefore both electrical and thermal resistance of the arms; and secondly, by integrating pads and leads to improve the heat sink effect. These results were confirmed by sheet resistance measurements of four different Greek cross designs which demonstrated that the proposed design rules reduced the Joule heating effects on the sheet resistance measurements by up to 25%.     

A numerical analysis of various cross sheet resistor test structures

Various four-terminal cross sheet resistor test structures were analyzed to determine the effect of the contact arm width and length on the measured sheet resistance. A nine-point finite difference approximation to the Laplace equation was used with a six-resistor equivalent circuit to solve for the sheet resistance measurement error. The error indicates the difference between the true sheet resistance and the sheet resistance calculated from the van der Pauw formula. The analysis demonstrates that many novel designs are possible. In particular, the Greek-cross sheet resistor is a valid van der Pauw test structure if the arm length is greater than the arm width. This test structure is important in that it allows the accurate measurement of the sheet resistance of a very small region whose width is limited only by the fabrication technology.     

洁净室散发的VOC的特性与测量

现代半导体洁净室中，生产过程所产生的有机挥发物（VOC）已成为影响产品品质的关键问题之一。本文对洁净室里VOC的来源进行了分析，并对人体和洁净室结构材料产生的VOC的特性和测量方法进行了讨论。     

激光雷达散射截面的比对测量法及其精度检测

野外目标激光雷达散射截面(LRCS)的测量通常使用比对测量方法.该方法受到测量系统激光光束模式,激光功率稳定性,大气吸收、散射和湍流,背景的激光漫反射回波,系统探测电路噪声等因素的影响.其中,测量系统激光光束模式是最重要的影响因素,造成了比对测量方法中LRCS测量精度难以客观、全面检测的问题.因此,在介绍LRCS的比对...     

Remote optical measurement of temperature using luminescent materials

A novel method of temperature measurement using optical fibres and luminescent materials is demonstrated. The delay time of an excited state in an inorganic material is shown to vary with temperature, and this is readily measured via the phase-shift technique.     

Thermal testing using oscillation based test structures

With slight modification, the oscillation based test structures originally implemented for a go-no-go test can also be used for thermal testing. The idea is described in a case study of the lowpass Sallen and Key filter and the notch filter. The approach can be generalised to the oscillation based test structures of other types of analogue circuits.     

Latch-up characterization using novel test structures andinstruments

A test structure for quickly determining the latch-up sensitivity of different geometries and the technological solutions in CMOS processes is presented. The structure permits the measurement of triggering and holding voltages with a simple oscilloscope and a voltage source. The device consists of an integrated astable oscillator (based on a p-n-p-n structure) that must be characterized. The good behavior of the measurement set-up is demonstrated by designing, fabricating and characterizing the latch-up of two different CMOS technologies using the test structure and instruments. Furthermore, the use of simple digitizing oscilloscopes facilitates obtaining statistical latch-up data     

Evaluation of the thermal resistance of Al---Cu electromigration test structures

The knowledge of the actual temperature of a metal line is fundamental in electromigration tests. It depends on the feasibility of thermal resistance measurements on the test structures. This work deals with the typical problems associated with the evaluation of the thermal resistance of Al---Cu test structures. As a consequence of significant copper-precipitation-induced resistance drops during high temperature electrical and thermal characterisation of the lines, it is shown that the derived thermal resistance value is a decreasing function of the measurement elapsed time. Thermal characterisations performed at temperatures lower than those typically used] allowed us to overcome this kind of problem.     

用ADC实现非标准方波信号的频幅同测

针对原测试非标准方波方波信号幅度和频率的测量电路分离的缺点,采取用PC104控制高速ADC和高速FIFO对非标准方波信号进行测量,配合一定的软件算法,可同时测得被测信号的频率和幅度值。通过对信号发生器输出的非标准方波的实际测量,证明了所述方法的正确性与可行性,该方法可避免传统测试方法中测量电路复杂且分离,测试方法不能统一的缺点。可用于工程应用中需要同时测量信号频率和幅度的测试系统,有效提高测量效率。     

Low-voltage micromechanical test structures for measurement of residual charge in dielectrics

Analysis of residual dielectric charge levels using micromechanical test structures is often difficult because the application of high bias voltages across thin dielectrics alters charge levels in the dielectric, thereby skewing measurement results. The use of low-voltage test structures to overcome this problem is demonstrated, and the technique is illustrated by evaluating residual charge levels in silicon oxide.     

Ground-penetrating radar measurement of soil water content dynamics using a suspended horn antenna

A ground-penetrating radar (GPR) with a suspended horn antenna was used to obtain continual measurement of near-surface soil water content dynamics within a well-defined footprint. Water contents inferred from radar surface reflectivity (SR) were in agreement with gravimetric measurements from the top 1-cm soil layer. This sensitivity to top 1 cm was confirmed by comparison of SR with deeper measurements (1-5 cm) obtained by time-domain reflectometry. Measurements over sand and silt loam showed the role of soil type in controling near-surface dynamics of soil water due to evaporation and drainage processes. GPR with a horn antenna provided insights into physical processes that could affect larger scale radar platforms (air- or spaceborne) and enabled verification of radar measurements at well-defined spatial scales and detailed temporal resolutions not available by other radar remote sensing systems.     

Addressing the challenges in solder resistance measurement for electromigration test

In the continuous drive for smaller chips with more functionality, I/O counts and power requirements increase. This leads to a growing concern on the electromigration (EM) reliability of solder joints in the high-density flip-chip package. For solder EM tests, it is a great challenge to detect early EM failure since the 10% change in resistance is very small due to the small initial resistance of the solder. Furthermore, the small change in resistance can often be masked by the parasitic resistance in the interconnect connecting the solder daisy chain type structures commonly employed in EM tests. The Wheatstone bridge method has been reported to address the inaccuracy associated with the use of Four-probe measurement method in solder EM tests successfully. In this work, we describe the use of Kelvin double bridge configuration that can further increase the accuracy of the bump resistance measured.     

Null holographic test structures for the measurement of overlay andits statistical variation

Results are presented on the use of null wire segment holograms for the in-line assessment of mask alignment errors in the integrated circuit fabrication process. Process variations are detected by measuring the light intensity generated by a hologram designed to project a null image. To detect alignment errors, the mask for the wire segment hologram (WSH) is distributed between two mask layers. If the two sets of diffracting structures defined by the masks are transferred to the wafer with perfect registration, the result is an area of light cancellation (null) in the image plane. Increased mask misalignment leads to imperfect wavefront cancellation, which is manifested as an increase in light intensity in the null region. In order to characterize misalignment under controlled conditions, the two portions of the holographic test structure were initially recombined into a single structure but with intentional misalignment between the two portions designed into the mask. The technique was then used to characterize the alignment errors between two separate masks with the actual fabricated offsets measured using atomic force microscopy. Initial results indicate the technique is capable of resolving 0.1-μm mask misalignment for a 1-μm minimum feature process     

采用脉冲红外成像法的表面下暗藏物蓄热系数的测量

近年来,脉冲红外成像无损评估方法已成功应用于航空航天、汽车制造、新材料等领域.但是对于很多应用,仅发现材料中存在缺陷是不够的,还需要对表面下缺陷热特性进行识别.实验设计制作了一个不锈钢平底孔试件,为了模拟表面下不同性质的暗藏物,在平底孔内分别埋入水、油、石蜡及空气.在试件表面施加均匀脉冲面热源后,试件表面及表面下暗藏物...     

A new resistance measurement technique applicable tohigh-temperature superconducting materials at microwave frequencies

A two-gap electrically floating resonant strip was used for surface resistance measurements of the high-temperature superconductor YBa₂Cu₃O_7-δ. The method is simple, has no electrical contact, operates at various resonant frequencies, and requires only a small sample. An analysis that allows for the accurate design of the strip dimensions to produce a desired resonant frequency was used. Experimental measurements on resonant frequencies in X- and Ku-band (8-18 GHz) agree well with the calculations. The method allows one to extract the normalized surface resistance of the sample from transmission coefficient measurements at the resonant frequency. These normalized values compare favorably to the Mattis-Baredeen theory taken in the local limit. The resonant strip in waveguide should have applications in high-temperature superconductive material characterization and in the development of waveguide superconductive filters     

FMM算法用于二维复杂散射体的RCS计算

利用快速多极子算法(FMM)计算任意形状二维电大尺寸导体加介质体目标的电磁散射，介质体为镶嵌在电大尺寸金属体上的有耗介质。建立金属一介质体的混合积分方程，用共轭梯度法和场量叠代的方法计算散射场，在叠代过程中用快速多极子方法，大大降低计算时间和减小内存要求。数据结果表明该方法的准确和高效。     

利用140 GHz雷达实现目标缩比模型的RCS测量与成像

构建了140 GHz频段的单基雷达用于缩比模型的高分辨力成像和雷达散射截面积(RCS)测量。雷达的相干收发机用全固态的方式实现,其发射信道采用一个Ka波段频率源驱动的倍频链作为本振,在5 GHz的带宽内实现了0.5 mW的输出功率,接收机采用基于肖特基二极管的次谐波混频器实现相干接收。该雷达RCS测试系统显示出高信噪比的特点,获得了大于100 dB的动态范围和3 cm的成像分辨力。除了可实现对目标的逆合成孔径成像,该系统还可完成对旋转目标全方位角的RCS测量。利用该系统对某航空母舰1/720th模型进行了成像实验和RCS测量,模拟了全尺寸目标在P波段的结果。所获得的数据根据缩比定律可为P-波段雷达设计提供参考。     

The removal of airborne molecular contamination in cleanroom using PTFE and chemical filters

Cleanroom contamination and its impact on the performance of devices are beginning to be investigated due to the increasing sensitivity of the semiconductor manufacturing process to airborne molecular contamination (AMC). A clean bench was equipped with different filter modules and then most AMC in the cleanroom and in the clean bench was detected through air-sampling and wafer-sampling experiments. Additionally, the effect of AMC on device performance was examined by electrical characterization. A combination of the NEUROFINE PTFE filter and chemical filters was found to control metal, organic, and inorganic contamination. We believe that the new combination of filters can be used to improve the manufacturing environment of devices, which are being continuously shrunk to the nanometer scale.