High Resolution Sem Imaging of Multilayer Thin Films

1995 ◽  
Vol 382 ◽  
Author(s):  
J. R. Kingsley ◽  
I. D. Ward ◽  
J. P. Vitarelli

ABSTRACTThe high resolution capability of the JEOL JSM-890 In Lens Field Emission Scanning Electron Microscope (ILFESEM) is used for the routine determination of both film thicknesses and surface morphologies from a single sample. This single sample approach is possible because of the 0.7 nm resolution of the instrument, and the simple sample preparation. In many cases, the desired information can be obtained from a simple cleave of the sample.

2011 ◽  
Vol 19 (5) ◽  
pp. 22-25 ◽  
Author(s):  
Dominik Greif ◽  
Daniel Wesner ◽  
Dario Anselmetti ◽  
Jan Regtmeier

When studying highly resolved scanning electron microscope images of cell surfaces, the question arises, whether the observed patterns are real or just artifacts of the cell preparation process. The following steps are usually necessary for preparation: fixation, drying, and metal coating. Each step might introduce different artifacts. Clever techniques have been developed to dry cells as gently as possible, for example critical point drying with different organic solvents and CO2. Instrument manufacturers also have taken account of this issue, for example, through the realization of the environmental scanning electron microscope (ESEM), operating with a low-vacuum environment saturated with water so that samples might stay hydrated. Another approach is the extreme high-resolution scanning electron microscope (XHR SEM), where the electron beam is decelerated shortly before reaching the sample. This technique requires no metal coating of the sample. Cryo-SEM also may be used, where no sample preparation is required beyond freezing in a high-pressure freezer or other cryo-fixation device. Then the cell can be examined in the frozen, hydrated state using a cryostage. However, at least some kind of preparation is necessary for SEM imaging, and we wanted to find out what changes the preparation makes on the cell surface.


Author(s):  
K. Ogura ◽  
A. Ono ◽  
M. M. Kersker

In general, various improvements have been made to SEM vacuum systems, and clean high vacuum specimen chambers are now routinely available. However, in the ultra high resolution scanning electron microscope, the prevention or reduction of contamination on the specimen surface has recently become an important subject when SEM imaging is done at higher than 200,000x magnification using a very fine electron probe. Typically, the specimen carries hydrocarbon gas molecules which are the source of the contamination, into the SEM. They adhere not only to the specimen surface but may also incorporated in the specimen, most typically in biological specimens, and cannot be reduced by the anti-contamination device of the SEM. Recently, a specimen heating holder was used in a JSM-890 ultra high resolution SEM, to reduce the contamination deposition on the specimen surface during SEM imaging. Using this holder, the specimen can be heated up to 300°C inside the SEM. Images 1 to 4 in Fig. 1 are the secondary electron images showing the cone-shaped deposition of contamination on a platinum-coated carbon film at different heating temperatures. This platinum-coated film, which had been kept in wet and oily atmosphere for several weeks to insure it was well covered with hydro carbon gas molecules, was irradiated by an electron probe in a spot mode for 30sec. with 1×10−11 Amp. of probe current at 20kV. After the electron probe irradiation, the platinum-coated carbon film was tilted 45° for imaging. Image 1 in Fig. 1 shows the cone-shaped deposition of contamination when the specimen was not heated. Image 2 was at 35°C, Image 3 was at 55°C, and Image 4 in Fig. 1 was at 115°C. At higher than 120°C specimen heating temperature, the cone-shaped deposition of contamination could not be observed any more. On the other hand, we can heat up the specimen outside the SEM before we put the specimen into the SEM. Image 5 in Fig. 1 shows the results of specimen heating by a hair dryer. The same platinum- coated carbon film was heated by a hair dryer for 1 minute before it was intro- duced into the SEM, and was irradiated by the electron probe for 15, 30, and 45sec. in a spot mode. This 1 min. heating by a hair dryer shows almost same result as 55°C specimen heating in the SEM.


Author(s):  
Louis T. Germinario

A liquid nitrogen stage has been developed for the JEOL JEM-100B electron microscope equipped with a scanning attachment. The design is a modification of the standard JEM-100B SEM specimen holder with specimen cooling to any temperatures In the range ~ 55°K to room temperature. Since the specimen plane is maintained at the ‘high resolution’ focal position of the objective lens and ‘bumping’ and thermal drift la minimized by supercooling the liquid nitrogen, the high resolution capability of the microscope is maintained (Fig.4).


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):  
J. P. Langmore ◽  
N. R. Cozzarelli ◽  
A. V. Crewe

A system has been developed to allow highly specific derivatization of the thymine bases of DNA with mercurial compounds wich should be visible in the high resolution scanning electron microscope. Three problems must be completely solved before this staining system will be useful for base sequencing by electron microscopy: 1) the staining must be shown to be highly specific for one base, 2) the stained DNA must remain intact in a high vacuum on a thin support film suitable for microscopy, 3) the arrangement of heavy atoms on the DNA must be determined by the elastic scattering of electrons in the microscope without loss or large movement of heavy atoms.


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):  
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.


Author(s):  
Edward Coyne

Abstract This paper describes the problems encountered and solutions found to the practical objective of developing an imaging technique that would produce a more detailed analysis of IC material structures then a scanning electron microscope. To find a solution to this objective the theoretical idea of converting a standard SEM to produce a STEM image was developed. This solution would enable high magnification, material contrasting, detailed cross sectional analysis of integrated circuits with an ordinary SEM. This would provide a practical and cost effective alternative to Transmission Electron Microscopy (TEM), where the higher TEM accelerating voltages would ultimately yield a more detailed cross sectional image. An additional advantage, developed subsequent to STEM imaging was the use of EDX analysis to perform high-resolution element identification of IC cross sections. High-resolution element identification when used in conjunction with high-resolution STEM images provides an analysis technique that exceeds the capabilities of conventional SEM imaging.


Author(s):  
Alexander Sorkin ◽  
Chris Pawlowicz ◽  
Alex Krechmer ◽  
Michael W. Phaneuf

Abstract Competitive circuit analysis of Integrated Circuits (ICs) is one of the most challenging types of analysis. It involves multiple complex IC die de-processing/de-layering steps while keeping precise planarity from metal layer to metal layer. Each step is followed by Scanning Electron Microscope (SEM) imaging together with mosaicking that subsequently passes through an image recognition and Graphic Database System (GDS) conversion process. This conventional procedure is quite time and resource consuming. The current paper discusses and demonstrates a new inventive methodology of circuit tracing on an IC using known FIB Passive Voltage Contrast (PVC) effects [1]. This technique provides significant savings in time and resources.


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