Responses of Electric-Field Probes Near a Cylindrical Model of the Human Body

A theoretical and experimental study on the response of an E-field probe near a cylindrical model of the human body has been conducted. The body is simulated with a long cylindrical dielectric shell filled with saline water, and a single E-field probe oriented in various directions, or an orthogonal probe is heated near its surface. The model with the probe is illuminated by a TE or TM plane EM wave. The response of the probe was found to be strongly dependent on the probe location with respect to the direction of the incident EM wave, the probe separation from the model surface, the probe orientation and the polarization of the incident EM wave. The effect due to the dielectric shell on the probe response, with and without the presence of saline water, was carefully investigated. In all cases, the agreement between theory and experiment was found to be very good.     

Failure analysis of contact probe pins for SnPb and Sn applications

A study has been conducted to investigate the failure mechanism of pogo pin-type probe contacts. Probe pins are used for electrical test of microelectronic components in manufacturing. A false rejection of parts due to high probe contact resistance results in a penalty in cost and yield. The probe pin contact bears distinctive characteristics of failure compared to the conventional contact systems such as mechanical switches and interconnects. Moreover, the transition to Pb-free component leads demands understanding of different probe failure mechanisms between a SnPb and Sn surface. The objective of this study is to understand this unique failure mechanism and the effect of lead coating metals on probe pin life. This has not been clearly elucidated to date in spite of its significant impact on yield and cost of electronic package manufacturing. A simulated probe tester with 3-axes actuation capability was devised to mimic the actual test process. The force required to penetrate the surface oxide layer and develop electrical contact was measured. Contact resistance history revealed that probe pins mating to Sn surfaces failed earlier than pins used on SnPb surfaces. Through periodic inspection of probe pins using microprobe/EDS as a function of probe actuations, the general root cause of probe pin failure was found to be probe pin tip wear out associated with the Sn oxide growth on its surface. The matte Sn surface wears the probe pin more than SnPb due to the rough and abrasive nature of the matte Sn surface.     

基于GRIN透镜的内窥OCT探头设计

提出一种用于在体活检的光谱 OCT 内窥探头的设计方案,能够实现对生物组织器官深度信息的在体内快速动态实时扫描成像,在临床医学领域具有广阔的应用前景。文中对探头的设计进行了理论分析,对探头的加工和测试进行了系统的阐述。针对传统的 GRIN 探头设计,本文探头的设计提高了光学质量和机械健壮性。对于 OCT 探头的成像质量依赖于单模光纤和 GRIN 透镜之间的距离（玻璃垫片长度）,进行了建模和验证。实验得出将玻璃垫片长度控制在0．2 mm 左右,探头可以达到2 cm 左右的工作距离,工作距离范围内探头的远场光束发散角为0．0175°。     

The Electric-Field Probe Near a Material Interface with Application to the Probing of Fields in Biological Bodies

A theoretical model is formulated to determine the effect of an interface between different media on the response of an electric-field probe. The model used provides a "worst case" estimate of the interaction between the probe and the interface. The effect of the interface on the response of the probe is examined as a function of the size of the probe, the insulation on the probe, the load admittance at the terminals of the probe, the dissipation in the surrounding medium and the spacing between the probe and the interface. The use of electricity small bare and insulated probes to measure the field in the interior of biological bodies is discussed as an example. Measured results are shown to be in general agreement with the theory.     

Empirical method of calibrating a 4-point microarray for measuring thin-film-sheet resistance

The calibration of a 4-point probe used for sheet-resistance measurements of a thin-film sample is usually based on the calculation of a correction factor C, depending on the probe and sample dimensions. Based on the Van, der Pauw idea, a method of experimental calibration of the 4-point probe is given, if the probe dimensions are sufficiently small in comparison with the sample.     

Effect of coplanar probe pad design on noise figures of 0.35 μmMOSFETs

The effects of different coplanar ground-signal-ground (GSG) probe pads on the noise figure characteristics of submicron MOSFETs are presented. Devices with top-level metal as probe pads shielded by grounded bottom-level metal possess the most appropriate probe pad structure for characterising the noise performance of MOSFETs. Equivalent circuits of the probe pads are used to explain the different noise behaviours     

高精度TDR可调探头的研制及应用

概述印制板阻抗设计的重要意义,在此基础上阐述研制测试印制板阻抗的高精度TDR可调探头的目的和制作原理;并将此款可调探头与固定探头做测试对比、通过做MSA测试验证及与国外同类型的可调探头做测试对比,表明可调探头可满足印制板内真实阻抗线路的测量要求。     

SPM探针制造技术的研究和发展

探针是扫描探针显微镜的核心部分,结构及针尖的表面状态会影响此类仪器的操作性、可控制性、工作稳定性、可靠性以及其它性能的发挥。探针及其相关技术的研究进展成为人们十分关注的问题。探针对表面物理信息的检测是一个针尖与试样表面相互作用的过程,包含物理、几何关系,还包含表面微观化学作用及其它微观因素的影响。本文探讨探针与表面相互作用关系,并就近些年探针技术发展讨论探针性能、针尖及相应结构的改进,探针功能的拓展以及功能的组合,讨论相关制备技术方法、特点和相应检测条件、适用环境等。     

扫描探针制备技术的研究现状及发展

探讨了近几年来探针制备技术的发展和趋势,分别就探针检测性能的改进、探针结构、探针检测功能拓展及多通道信息采集组合探针等几方面,对相关制备技术的方法、特点以及相应检测条件、适用环境展开讨论,这些方面反映探针制备技术正朝着尖锐化、多样化、功能化和组合方向发展。     

Electrical probing of deep sub-micron integrated circuits using scanning probes

A new scanning probe microscopy technique for contact electrical probing of deep sub-micron integrated circuits is presented. The probe utilizes a conductive atomic force microscope micromachined tip to simultaneously measure nanometer resolution surface topography and acquire real-time high frequency electrical signals. Similar to conventional wire probers, the probe operates on a standard probe station in an ambient environment. The probe is capable of surface imaging and placement on features as small as 0.18 μm and is able to control and maintain a contact force to <1 μN, thus minimizing circuit damage. Electronics, integrated within the probe tip, enable 3 GHz bandwidth measurements with a capacitive loading of <120 fF. Measurements of 0.25 μm interconnect structures and polished silicon on insulator devices is presented.     

Control of scattering from probes for near-field antenna measurements by use of skirt

A novel approach to reducing the multiple reflections between the test antenna and the probe in near-field antenna measurements is proposed. Instead of absorbers, this approach makes use of a skirt on the probe to shield against the mounting structure behind the probe.     

Parameter Modeling for Wafer Probe Test

This paper presents the simulation of parameters for wafer probe test by finite-element modeling with consideration of probe over-travel (OT) distance, scrub, contact friction coefficient, probe tip shapes, and diameter. The goal is to minimize the stresses in the device under the bond pad and eliminate wafer failure in probe test. In the probe test modeling, a nonlinear finite-element contact model is developed for the probe tip and wafer bond pad. Modeling results have shown that the probe test OT, probe tip shape and tip diameters, contact friction between the probe tip and bond pad, as well as the probe scrub of the probe tip on bond pad are important parameters that impact the failure of interlayer dielectric (ILD) layer under bond pad. Comparison between probe test damage and wire bonding failure shows the degree of damage to both probe test and wire bonding on the same bond pad structures. In addition that, a design of experiment (DOE) probe test with different ILD and metal thickness is carried. The correlation between the modeling and the DOE test is studied. The results show that the modeling solution agrees with the DOE probe test data. Modeling results have further revealed that probe test can induce the local tensile (or bending) first principal stress in ILD layer, which may be a root cause of the ILD failure in probe test.     

熔拉与腐蚀光纤探针传输特性的研究

用实验方法测量了用熔拉或腐蚀的方法制备的光纤探针的传输效率随光纤圆锥角的变化关系,作出传输效率曲线,通过测定光纤探针传输效率的实验,我们看到:在小锥角的情况下,用熔拉法制备的光纤探针与腐蚀的方法制备的光纤探针的传输效率基本相同。在大锥角的情况下,用腐蚀法制备的光纤探针传输效率高于熔拉的方法制备的光纤探针的传输效率。在锥角为50.4°时,腐蚀的光纤探针传输效率为78.8%,熔拉的光纤探针传输效率为76.6%。在相同的条件下,两者的传输效率的差别随入射光波长的增加而下降。     

Suppression of reflections by directive probes in spherical near-field measurements

The influence of probe correction in spherical near-field measurements on signals from outside the test volume is investigated theoretically and experimentally. It is found that the suppression of reflections obtained by a directive probe is not disturbed by the probe correction. A geometric relation between the antenna "minimum sphere" and the probe pattern beamwidth is established, whose satisfaction guarantees the absence of numerical instabilities in the far-field computation. The condition is sufficient, but not necessary if the "minimum sphere" of the antenna is in the near field of the probe.     

New method for the Langmuir probe diagnostics of polymerizing plasmas

A pulsed Langmuir probe method of plasma diagnostics is proposed and validated for low-pressure, high-density, low-temperature plasmas capable of producing a nonconducting film on the probe surface. The method essentially involves cyclic probe-surface cleaning by ion bombardment. A switching pattern of probe potential is designed, taking into account the mechanism by which a space-charge region is formed near the probe. The method is successfully employed in an experiment on inductively coupled CHF₃ and Ar plasmas. The results of the experiment are presented.     

Characterization of probe contact noise for probes used inwafer-level testing

The characteristics of probe contact noise for tungsten probes used in wafer-level testing are presented. The effects of the biasing current and the probe contact resistance, R_c, on the probe contact noise were investigated. This information is required for low-noise probe design as well as for reduction of the contact noise effects on sample noise measurements. The results show that the spectral density of the probe contact noise voltage has a 1/f frequency dependence and is proportional to V_c²R_c^Γ where Γ is a constant which has a value between -0.1 and 0.6 depending on the conditions of the contact interfaces     

Complex-Point Dipole Formulation of Probe-Corrected Cylindrical and Spherical Near-Field Scanning of Electromagnetic Fields

A probe-corrected electromagnetic theory based on complex-point dipoles is presented for computing the field of an arbitrary source of finite extent (for example a test antenna) from measurements of its near field on a cylindrical or spherical scanning surface. By representing the probe with complex-point dipoles, probe correction is achieved by simple factors that involve Hankel functions evaluated at complex points. Only four complex-point dipoles are needed to represent a typical precision probe used in near-field measurements. The theory uses neither translation and rotation theorems nor differential operators. One disadvantage of the theory is that it employs nonlinear optimization to determine the parameters of the probe model. The complex-point dipole representation of the probe makes realistic simulations of near-field scanning systems straightforward. The cylindrical theory is validated through a numerical example. The spherical theory is validated by experimental data.     

Vector theory of cross-phase modulation: role of nonlinear polarization rotation

We develop a vector theory of cross-phase modulation (XPM) capable of describing nonlinear coupling between two pulses of different wavelengths and arbitrary states of polarization. We focus for simplicity on the pump-probe configuration and use it to investigate the temporal and spectral polarization effects occurring inside an optical fiber. Using the Stokes-vector formalism we show that the probe polarization changes in general through XPM-induced nonlinear polarization rotation. In the absence of dispersion-induced probe broadening, such nonlinear changes in the probe polarization do not affect the temporal shape of the probe pulse but produce a multipeak spectrum whose different spectral peaks have different states of polarization. When dispersive effects are included, even the shape of the probe pulse becomes polarization dependent, and different parts of the pulse develop different states of polarization. Such nonlinear polarization effects lead to novel phenomena such as polarization-dependent compression and splitting of the probe pulse.     

Novel low-cost planar probes with broadside apertures for nondestructive dielectric measurement of biological materials at microwave frequencies

Novel planar-type probes were developed to demonstrate the possibility of replacing the existing high-cost open-ended coaxial probes. The planar probes of this study define an aperture on the broadside of the probe body. In this way, the contact area can be maximized and/or customized according to specific medical needs. The probes with various aperture sizes and shapes can also be fabricated simultaneously in a single batch process. Three probes are developed in this paper: a probe combining two laminates, a microelectromechanical systems (MEMS)-based probe with a single benzocyclobutene (BCB) layer on a quartz substrate, and another MEMS probe with two BCB layers defined on a silicon substrate. The third probe was specifically designed for monolithic integration with driving circuits on a single substrate. Limitations in the high-frequency performance of the planar probes were carefully studied, and higher order modes and incomplete shielding were found to be the main causes. The measurement results of each probe showed excellent compatibility with those of the open-ended coaxial probe up to almost 40 GHz. The proposed planar-type probes have great potentials for practical medical applications in view of low cost, disposability, and monolithic integration capability with the driving circuits.     

A Multifilament Method-of-Moments Solution for the Input Impedance of a Probe-Excited Semi-Infinite Waveguide

The input impedance and surface currents of a probe-excited, short-circuited semi-infinite waveguide are determined by the method of moments. Expressions are given for the impressed electric field used to excite the probe from the coaxial source input using a semi-infinite-waveguide Green's function, and expressions are given for a free-space approximate impressed electric field which arises from the coaxial source input. The method-of-moments formulation used is based on a multifilament current approximation and solves for the surface currents of the probe as a function of probe angle around the probe. Comparison of theory and experiment is made.