Electron beam testing: Problems in practice

Electron beam testing has now become an almost indispensable design verification aid for very large scale ICs. The test preparations for circuit analysis are very important as the purpose of these preparation is to ensure that the integrated circuit is driven as it was during characterization on the computerized test system. The same applies when the circuit is being irradiated by the electron beam. This involves the use of preparation techniques such as plasma etching and plasma cleaning, the development of measuring equipment, determining suitable parameters for the electron probe and constantly checking how the circuit is functioning. The actual circuit analysis is carried out in two stages – first the defective block is located and then the individual circuit responsible for the design weakness pinpointed. Cases may arise where measurements on interconnections covered by an oxide layer are required. It might also be necessary to impress signals on certain nodes using a mechanical probe or to separate the circuits.     

Electron beam testing: Methods and applications

There are eight e-beam methods of testing integrated circuits. The principle and performance of the various methods will be discussed in this paper. The performance criteria are voltage resolution and the frequency range in which voltage changes can be detected. From this it is possible to decide which methods are best suited for testing the various IC types available today.     

Electron beam blanking systems

Electron beam blanking in the scanning electron microscope (SEM) by deflection over a chopping aperture is reviewed. The first part is concerned with electron beam deflection structures and driving methods, the second part with electron optics of deflection blanking systems in the SEM.     

Electrohydraulic fatigue apparatus for testing at cryogenic temperature

A closed-loop electrohydraulic fatigue apparatus was constructed for testing from above room temperature to 77 K. Several important improvements in the electronics of the reference function generator and the servo controller over previous apparatus are described. The electronics allows cool-down of the specimen to 77 K at zero stress, correction for thermal contraction, and then cyclic fatigue testing under strain control, all without interruption of hydraulic power.     

Electron beam modifications of InP surfaces

InP surfaces have been modified by using the intense electron beam of a V.G. HB501 STEM and subsequently examined in the same instrument using the reflection microscopy geometry. The surface changes can be divided into two parts; first, a fairly local removal of material, and second, more widespread effects including faceting and the formation of an oxide layer which extends for several microns around the point of incidence of the electron beam.     

Electron beam depth profiling in semiconductors

A technique for depth profiling of semiconductors is described based upon the measurement of induced junction currents as a function of beam energy. Using the known energy loss relation and electron hole pair generation rate it is possible to infer quantitative information about the semiconductor structures as a function of depth between ～0·02 and ～5 μm for silicon. Examples of the application of the technique to implanted and electron beam pulse annealed silicon and to a JFET transistor are described. Calculations of diffusion length limits, junction depths, poly-silicon thickness, epitaxial layer thickness and surface recombination velocity are discussed.     

电子束加工技术及其应用

电子束加工技术是近年发展起来的一种先进制造技术,其在材料表面改性、机械加工等方面的应用已受到广泛关注.主要介绍电子束在表面工程、打孔和焊接等方面的应用.     

Electron beam damage of amorphous synthetic polymers

The electron beam damage of amorphous polymers (PVC, PVDC, PTFE, PVDF, Hypalon, PES, Horizon and PDMS) has been measured by the elemental loss using EDX analysis. An attempt has been made to identify and eliminate the experimental error which would influence the measured decay curves. Only Cl and F in some polymers were found to be volatile. The PVC-Cl decay curves were compared with UV and IR spectra at different stages of irradiation and it has been concluded that some Cl is trapped in a more stable structure with conjugated double bonds. The formation of isolated double bonds and their destruction has been revealed by a staining technique for PVC, PMMA, PS and PC. It is likely that the mechanism of formation of isolated double bonds and their conversion to a more stable structure with conjugated double bonds is valid generally for all polymers. The staining peak can therefore be used as a universal technique for the beam sensitivity measurement.     

Electron beam damage of behenic acid films

The rate of fading of electron diffraction patterns of behenic acid monolayer crystals as well as multilayer crystals was measured at 100 kV at room temperature to investigate the dependence of beam damage on specimen thickness. The diffracted intensities for monolayers and double layers decreased nearly exponentially with electron exposure; however, the intensities for multilayers were unchanged during initial electron exposures, often increased temporarily and then decreased with electron exposure. The critical dose, D_e, defined as the dose at which the diffracted intensity falls to 1/e of its initial value, was 1.0 electrons/Ų for the monolayers, 1.8 electrons/Ų for the double layers and more for multilayers. These results lead to the conclusion that D_e for behenic acid increases nearly linearly with specimen thickness in the range of about 25–100 Å for dose rate of 0.1–2 electrons/Ų min.     

The relative stability of a mercury stain at room temperature and liquid helium temperature

Observations of the localization of the mercurial stain TAMM [tetrakis (acetoxymercuri) methane] have been made at room temperature and liquid helium temperature. Mercurial stains do not maintain a fixed position at room temperature in the electron microscope. In order to record room temperature micrographs with the minimum possible dose, a special single-electron-counting electron microscope system was used. Micrographs were taken at liquid helium temperature using a prototype microscope with a superconducting electron objective lens. Tropomyosin paracrystals were chosen as a convenient test object. At room temperature the fine banding pattern of the paracrystals was barely resolvable or not resolvable at all. At liquid helium temperature the fine banding pattern of the paracrystals was easily observed and more than one micrograph could be taken before the banding pattern faded. These observations indicate that this mercurial stain is more stable in position at liquid helium temperature than at room temperature.     

Design and construction of a guarded hot plate apparatus operating down to liquid nitrogen temperature

A double-sided guarded hot plate apparatus (GHP) is specifically designed, fabricated, and constructed for the measurement of thermal conductivities of insulation specimens operated down to liquid nitrogen temperature (-196 °C), at different controlled pressures from 0.005 Pa to 0.105 MPa. The specimens placed in this apparatus are 300 mm in diameter at various thicknesses ranging from 4 mm to 40 mm. The apparatus is different from traditional GHP in terms of structure, supporting and heating method. The details of the design and construction of the hot plate, the cold plates, the suspensions, the clampings, and the vacuum chamber of the system are presented. The measurement methods of the temperatures, the input power, the meter area, and the thickness of the specimens are given. The apparatus is calibrated with teflon plates as sample and the maximum deviation from the published data is about 6% for thermal conductivity. The uncertainties for the measurement are also discussed in this paper.     

汽车铝合金薄板零件电子束焊装过程及其计算机辅助工艺设计

针对汽车铝合金薄板焊装零件的电子束焊接制造过程,提出计算机辅助工艺设计(CAPP)的需求和必要。应用Unigraphics(UG)提供的二次开发工具OpenGRIP语言,开发有关应用程序。实践表明,CAPP对零件设计,制造工艺以及设备的设计和应用控制均有指导意义。     

Cryo-TEM liquid nitrogen splash guard

A simple aluminium splash guard provides protection for both microscopes and operators during cryo-transfer procedures.     

Electron beam current measurement in the electron microscope

Two devices for measuring the beam current in an electron microscope are described; a Faraday cage rod for accurate absolute measurements in the specimen position and a collector plate mounted in the viewing chamber, which may be used continuously during experiments, for relative current measurements. Results of experiments to determine the effect of secondary electrons on, and choice of material of, the collector plate are presented. An example of the use of the collector plate as a photometer is given.     

Mass loss rate in collodion is greatly reduced at liquid helium temperature

The mass thickness of collodion films has been monitored at several temperatures, under conditions typical of electron microscopy, through the use of an electron energy loss spectrometer. Compared to room temperature, only a five-fold reduction in the rate of mass loss was observed through the use of a commercial liquid nitrogen cooled stage; in contrast, the rate of mass loss was reduced more than one hundred fold when these films were held at liquid helium temperature.     

条纹计数法干涉型光纤液位传感器的电路法判向及其温度补偿

提出利用RC移相电路获得相位差为90°的输出信号,以取代相位差为90°的双光路,对干涉条纹计数时做正确判向,可以简化条纹计数法光纤Fabry-Perot腔干涉型液位传感器的结构,使之更实用和集成化。分析了F-P腔长与温度变化的关系,说明选择合适的腔体材料以及波纹管的热膨胀系数和初始长度,可在温度变化时保持腔长的较小变化。提出在传感器上安置温度传感器,预先测出F-P腔长与温度变化的关系,然后利用软件法对传感器输出进行温度补偿。实验表明:该软件补偿法能够较好的补偿温度变化对液位测量时造成的影响。