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"Scanning Electron Microscope, an Interface and a Method for Observing an Object within a Non-Vacuum Environment" in Patent Application Approval...

May 22, 2014



"Scanning Electron Microscope, an Interface and a Method for Observing an Object within a Non-Vacuum Environment" in Patent Application Approval Process

By a News Reporter-Staff News Editor at Politics & Government Week -- A patent application by the inventors SHACHAL, Dov (Rehovot, IL); DE PICCIOTTO, Rafi (Carmei Yosef, IL), filed on October 30, 2012, was made available online on May 8, 2014, according to news reporting originating from Washington, D.C., by VerticalNews correspondents.

This patent application is assigned to B-nano Ltd.

The following quote was obtained by the news editors from the background information supplied by the inventors: "High resolution microscopy is used in research and development, quality assurance and production in diverse fields such as material science, life science, the semiconductor industry and the food industry.

"Optical microscopy, dating back to the seventeenth century, has reached a brick wall defined by the wavelength of deep Ultra Violet photons, giving a finest resolution of about 80 nm. The popularity of optical microscopy stems from its relative low price, ease of use and the variety of imaging environmental parameters--all translated to availability.

"Scanning electron microscopy provides a much finer resolution (down to a few nanometers), but in order to achieve this high resolution the inspected object must be placed in a vacuum environment.

"Determining a Working Distance

"In non-vacuum Scanning Electron Microscopes, the distance between the object and the microscope (also referred to as 'working distance') is of the order of a few to tens microns. Knowing the exact working distance is important for resolution and contrast optimization, for safe imaging of an object without contacting the optics of the microscope, for reducing contamination generated by such a contact, and for generating a focused image by setting the focusing lens accordingly. There is a growing need to provide a fast and accurate method and system for determining the working distance.

"Reducing the Working Distance

"The working distance between the object and the optics of the microscope should be as small as possible but large enough to prevent the object from contacting the microscope or otherwise contaminating the microscope. There is a growing need to provide an optimal trade off between the working distance and contamination hazards."

In addition to the background information obtained for this patent application, VerticalNews journalists also obtained the inventors' summary information for this patent application: "According to an embodiment of the invention a method is provided. The method is for observing an object that is positioned in a non-vacuum environment, the method includes: generating an electron beam in the vacuum environment; scanning a region of the object with the electron beam while the object is located below an object holder; wherein the scanning comprises allowing the electron beam to pass through an aperture of an aperture array, pass through an ultra thin membrane that seals the aperture, and pass through the object holder; wherein the ultra thin membrane withstands a pressure difference between the vacuum environment and the non-vacuum environment; and detecting particles generated in response to an interaction between the electron beam and the object.

"According to an embodiment of the invention a scanning electron microscope is provided. The scanning electron microscope includes: an electron beam source positioned in a vacuum environment; the electron beam source is adapted to generate an electron beam; an interface between the vacuum environment and a non-vacuum environment in which an object is positioned, the interface comprises an aperture array sealed by an ultra thin membrane that is substantially transparent to the electron beam and withstands a pressure difference between the vacuum environment and the non-vacuum environment; an object holder; a scanner that scans a region of the object with the electron beam while the object is located below the object holder; wherein the electron beam passes through an aperture of the aperture array, passes through the ultra thin membrane, and passes through the object holder; and a detector that detects particles generated in response to an interaction between the electron beam and the object.

"According to an embodiment of the invention a method is provided. The method is for observing an object that is positioned in a non-vacuum environment, the method includes: illuminating an area of an object with an electron beam; wherein the electron beam is generated in the vacuum environment and passes through an aperture of an aperture array and passes through an ultra thin membrane that seals the aperture; wherein the ultra thin membrane withstands a pressure difference between the vacuum environment and the non-vacuum environment; detecting particles generated in response to an interaction between the electron beam and the object; and determining a distance between the object and the ultra thin membrane in response to detected particles.

"According to an embodiment of the invention a scanning electron microscope is provided. The scanning electron microscope includes: an electron beam source positioned in a vacuum environment; the electron beam source is adapted to generate an electron beam; optics configured to direct the electron beam towards an area of the object; an interface between the vacuum environment and a non-vacuum environment in which an object is positioned, the interface comprises an aperture array sealed by an ultra thin membrane that is substantially transparent to the electron beam and withstands a pressure difference between the vacuum environment and the non-vacuum environment; at least one detector that detects particles generated in response to an interaction between the electron beam and the object; and a controller configured to determine a distance between the object and the ultra thin membrane in response to detection signals generated by the at least one detector.

"According to an embodiment of the invention a method is provided. The method is for aligning an electron beam and an aperture of an aperture array, the method includes: obtaining an image of a first area of the aperture array; wherein the first area comprises multiple apertures of the aperture array; calculating a spatial relationship between a selected aperture of the multiple apertures and a reference location within the first area; aligning an electron beam with the reference location in response to the spatial relationship; and obtaining an image of a region of an object that is positioned in a non-vacuum environment; wherein the obtaining comprises scanning the region by an electron beam that is generated in a vacuum environment, passes through the selected aperture and passes through an ultra thin membrane that seals the selected aperture; wherein the ultra thin membrane withstands a pressure difference between the vacuum environment and the non-vacuum environment.

"According to an embodiment of the invention a scanning electron microscope is provided. The scanning electron microscope includes: an electron beam source positioned in a vacuum environment; the electron beam source is adapted to generate an electron beam; an interface between the vacuum environment and a non-vacuum environment in which an object is positioned, the interface comprises an aperture array sealed by an ultra thin membrane that is substantially transparent to the electron beam and withstands a pressure difference between the vacuum environment and the non-vacuum environment; optics configured to scan, with an electron beam, a first area of the aperture array and scan a second area of the aperture array; wherein the first area comprises multiple apertures of the aperture array; wherein the second area is smaller than the first area and comprises a selected aperture; at least one detector that detects particles generated in response to an interaction between the electron beam and at least one entity out of the interface and the object; and a controller configured to: calculate a spatial relationship between a selected aperture of the multiple apertures and a reference location within the first area; and control an alignment of the electron beam with the reference location in response to the spatial relationship.

BRIEF DESCRIPTION OF THE DRAWINGS

"FIG. 1 illustrates a portion of a scanning electron microscope according to an embodiment of the invention;

"FIG. 2 illustrates a portion of a scanning electron microscope according to another embodiment of the invention;

"FIG. 3 illustrates an object, a sample holder, non-vacuum environment and a chamber according to an embodiment of the invention.

"FIG. 4 illustrates a chamber that includes a force applying component according to an embodiment of the invention;

"FIG. 5 is a cross section of an object that is an electrochemical cell and of a sample holder according to an embodiment of the invention;

"FIG. 6 illustrates a method for observing an object that is positioned in a non-vacuum environment, according to an embodiment of the invention;

"FIGS. 7 and 8 illustrate a first area of an aperture array according to embodiments of the invention;

"FIG. 9 illustrates a method for aligning an electron beam and an aperture of an aperture array, according to an embodiment of the invention;

"FIG. 10 illustrates an object holder and multiple objects according to an embodiment of the invention;

"FIG. 11 illustrates a portion of a scanning electron microscope and various particles according to an embodiment of the invention;

"FIG. 12 illustrates a relationship between working distance and electron distribution according to an embodiment of the invention;

"FIG. 13 illustrates a ratio between the fraction of electrons that do not pass through an aperture array and the fraction of electrons that pass through the aperture array, according to an embodiment of the invention;

"FIG. 14 illustrates a contrast, according to an embodiment of the invention;

"FIG. 15 illustrates a method for observing an object that is positioned in a non-vacuum environment, according to an embodiment of the invention;

"FIG. 16 illustrates an effect of placing a shutter on the collection efficiency according to an embodiment of the invention;

"FIG. 17 illustrates a relationship between working distances and a calculated shutter diameter for onset of signal saturation (equilibrium point) according to an embodiment of the invention;

"FIG. 18 illustrates a detector that includes two concentric annular detector elements (electrodes) according to an embodiment of the invention;

"FIG. 19 illustrates collection efficiencies for the detector of FIG. 18, as a function of working distance according to an embodiment of the invention;

"FIG. 20 illustrates an off axis illumination according to an embodiment of the invention;

"FIG. 21 illustrates an annular BSE detector that has two segments according to an embodiment of the invention;

"FIG. 22 illustrates an off-axis illumination according to an embodiment of the invention;

"FIG. 23 illustrates a relationship between a difference signal and working distance for off axis illumination according to an embodiment of the invention;

"FIG. 24 illustrates on-axis and off-axis illumination according to an embodiment of the invention; and

"FIG. 25 illustrates a scanning electron microscope and another microscope according to an embodiment of the invention."

URL and more information on this patent application, see: SHACHAL, Dov; DE PICCIOTTO, Rafi. Scanning Electron Microscope, an Interface and a Method for Observing an Object within a Non-Vacuum Environment. Filed October 30, 2012 and posted May 8, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=6126&p=123&f=G&l=50&d=PG01&S1=20140501.PD.&OS=PD/20140501&RS=PD/20140501

Keywords for this news article include: B-nano Ltd.

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Source: Politics & Government Week


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