A Micromanipulator for Use in the Column of a Scanning Electron Microscope

Author(s):  
James B. Pawley

Used in the secondary electron mode, the Scanning Electron Microscope (SEM) produces an image of the outside surface of a microscopic sample which looks very similar to what one might expect to see if the sample was a diffusely illuminated macroscopic object viewed with the unaided eye. Part of the familiarity of such an image is associated with the fact that one seems to look at the sample rather than through it, as in the case with the conventional electron microscope or the high resolution light microscope. A resulting limitation is the fact that an object of interest cannot be observed if it is below the outer surface. It has been shown (Gane and Bowden 1968) that useful surface hardness information can be obtained on a micro scale by observing the deformation produced when a small stylus, attached to a D'Arsonval meter movement, is brought to bear on the surface of a sample while it is in the SEM.

2013 ◽  
Vol 19 (2) ◽  
pp. 415-419 ◽  
Author(s):  
Policarp Hortolà

AbstractStudies of human bloodstains on nonbiological materials have been previously carried out using a high-vacuum scanning electron microscope (HV-SEM) in secondary-electron mode without any sample treatment. To assess whether biological substrates can affect the morphology of human erythrocytes in bloodstains, three fragments of different biological material (bone, shell, and wood) were smeared with peripheral human blood. Afterward, the bloodstains were directly examined in secondary-electron mode by an HV-SEM following a procedure initially standardized to be used in uncoated human bloodstains on stone. The obtained results suggest that HV-SEM is suitable for examining untreated bloodstains on biological substrate and that the morphology of erythrocytes in human bloodstains is not affected by the biological nature of the substrate. A cautionary issue regarding bloodstains on nondehydrated biological substrates is that the waiting time required for initiating the HV-SEM examination is by far higher than when using inorganic bloodstain substrates.


2000 ◽  
Vol 6 (S2) ◽  
pp. 764-765
Author(s):  
H. Kazumori ◽  
A. Yamada ◽  
M. Mita ◽  
T. Nokuo ◽  
M. Saito

A newly developed cold FE-GUN which enables to us to obtain large probe current and low emission noise, and conical strongly excited objective lens has been installed on the JSM-6700F Scanning Electron Microscope (SEM). In the range of accelerating voltages from 0.5 to 15kV, this instrument has got much better resolution as compared with in-lens type SEM (Ohyama et al 1986)(Fig. 1). We can obtain high-resolution secondary electron images with large samples (ex. 150mm ϕ×10mmH).Our old type objective lens (Kazumori et al 1994) has the limitation of working distance (WD), but the new lens enables us to work at very short WD at accelerating voltage of 15kV. As a result the spherical (Cs) and chromatic (Cc) aberration constants are 1.9mm and 1.7mm respectively at a WD of 3mm.In order to get large probe current, we increased emission current and got near the distance between the t ip of emi tter and the pr inciple plane of condenser lens.


Author(s):  
L.W. McDonald ◽  
R.F.W. Pease ◽  
T.L. Hayes

In previous studies from this laboratory the scanning electron microscope has been used to examine biological materials in the cathodo-luminescense and secondary electron modes. In these studies intact cells or even entire insects have been examined, some in the living state. Epithelial surfaces have been exposed and examined. Prior to the work to be described, no reports of the examination of tissue sections in the scanning electron microscope have been found, although sufaces of solid one millimeter cubes of tissue have been examined.In the present work blocks of solid tissue fixed in buffered aldehyde have been dehydrated in graded alcohols, embedded in paraffin, section at 4μ and examined successfully in the scanning electron microscope. These sections have been over 1 cm square and have been stained for subsequent comparative examination with the light microscope. With the scanning electron microscope in the secondary electron mode, magnifications of X5,000 have been found useful. In addition to the increased resolution as compared to the light microscope, a three dimensional image is obtained. An advantage over the conventional electron microscope is that tissue areas 1,000 times greater may be examined in the large sections without any obscuring grid bars, again with the three dimensional image. With the cathode ray display tube used, magnifications range from X30 to over X20,000


Author(s):  
S. Saito ◽  
H. Todokoro ◽  
S. Nomura ◽  
T. Komoda

Field emission scanning electron microscope (FESEM) features extremely high resolution images, and offers many valuable information. But, for a specimen which gives low contrast images, lateral stripes appear in images. These stripes are resulted from signal fluctuations caused by probe current noises. In order to obtain good images without stripes, the fluctuations should be less than 1%, especially for low contrast images. For this purpose, the authors realized a noise compensator, and applied this to the FESEM.Fig. 1 shows an outline of FESEM equipped with a noise compensator. Two apertures are provided gust under the field emission gun.


Author(s):  
Oliver C. Wells

The low-loss electron (LLE) image in the scanning electron microscope (SEM) is useful for the study of uncoated photoresist and some other poorly conducting specimens because it is less sensitive to specimen charging than is the secondary electron (SE) image. A second advantage can arise from a significant reduction in the width of the “penetration fringe” close to a sharp edge. Although both of these problems can also be solved by operating with a beam energy of about 1 keV, the LLE image has the advantage that it permits the use of a higher beam energy and therefore (for a given SEM) a smaller beam diameter. It is an additional attraction of the LLE image that it can be obtained simultaneously with the SE image, and this gives additional information in many cases. This paper shows the reduction in penetration effects given by the use of the LLE image.


Author(s):  
David Joy ◽  
James Pawley

The scanning electron microscope (SEM) builds up an image by sampling contiguous sub-volumes near the surface of the specimen. A fine electron beam selectively excites each sub-volume and then the intensity of some resulting signal is measured. The spatial resolution of images made using such a process is limited by at least three factors. Two of these determine the size of the interaction volume: the size of the electron probe and the extent to which detectable signal is excited from locations remote from the beam impact point. A third limitation emerges from the fact that the probing beam is composed of a finite number of discrete particles and therefore that the accuracy with which any detectable signal can be measured is limited by Poisson statistics applied to this number (or to the number of events actually detected if this is smaller).


Author(s):  
M.G. Rosenfield

Minimum feature sizes in experimental integrated circuits are approaching 0.5 μm and below. During the fabrication process it is usually necessary to be able to non-destructively measure the critical dimensions in resist and after the various process steps. This can be accomplished using the low voltage SEM. Submicron linewidth measurement is typically done by manually measuring the SEM micrographs. Since it is desirable to make as many measurements as possible in the shortest period of time, it is important that this technique be automated.Linewidth measurement using the scanning electron microscope is not well understood. The basic intent is to measure the size of a structure from the secondary electron signal generated by that structure. Thus, it is important to understand how the actual dimension of the line being measured relates to the secondary electron signal. Since different features generate different signals, the same method of relating linewidth to signal cannot be used. For example, the peak to peak method may be used to accurately measure the linewidth of an isolated resist line; but, a threshold technique may be required for an isolated space in resist.


Author(s):  
Becky Holdford

Abstract On mechanically polished cross-sections, getting a surface adequate for high-resolution imaging is sometimes beyond the analyst’s ability, due to material smearing, chipping, polishing media chemical attack, etc.. A method has been developed to enable the focused ion beam (FIB) to re-face the section block and achieve a surface that can be imaged at high resolution in the scanning electron microscope (SEM).


Author(s):  
Erik Paul ◽  
Holger Herzog ◽  
Sören Jansen ◽  
Christian Hobert ◽  
Eckhard Langer

Abstract This paper presents an effective device-level failure analysis (FA) method which uses a high-resolution low-kV Scanning Electron Microscope (SEM) in combination with an integrated state-of-the-art nanomanipulator to locate and characterize single defects in failing CMOS devices. The presented case studies utilize several FA-techniques in combination with SEM-based nanoprobing for nanometer node technologies and demonstrate how these methods are used to investigate the root cause of IC device failures. The methodology represents a highly-efficient physical failure analysis flow for 28nm and larger technology nodes.


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