CN217084756U - Sample stage with ellipsoidal reflector and scanning electron microscope - Google Patents

Abstract

The utility model discloses a sample platform and have scanning electron microscope of this sample platform with ellipsoid speculum, this sample platform include sample platform body and ellipsoid speculum, and the bottom of ellipsoid speculum is connected rather than all around along sample platform body, and the downside focus of ellipsoid speculum is located the loading end of sample platform body. The utility model provides a have sample platform of ellipsoidal speculum and have this sample platform's scanning electron microscope, utilize light or electron that ellipsoidal speculum had from one of them focus transmission can be in the characteristic that another focus converged, converge the signal electron that surpasss coaxial electron detector and survey the size, make it survey the size internal reflection to coaxial electron detector, improve coaxial electron detector's detection efficiency to can replace the scheme that adds reverse electric field at the sample platform.

Description

Sample stage with ellipsoidal reflector and scanning electron microscope

Technical Field

The utility model relates to a scanning electron microscope technical field especially relates to a sample platform and have scanning electron microscope of this sample platform with ellipsoid shape speculum.

Background

Scanning Electron Microscope (SEM), abbreviated Scanning Electron Microscope, is a common micro-analyzer for modulating and imaging various physical signals excited by a focused Electron beam when Scanning on a sample surface.

The electronic detector is used for detecting signal electrons such as secondary electrons, back scattering electrons and the like in physical signals in a scanning electron microscope, wherein the coaxial detector is arranged right above the sample stage, is positioned in the lens barrel or outside the lens barrel and is used for detecting the secondary electrons and the back scattering electrons reflected towards the lens barrel.

At present, the sample stage of the mainstream scanning electron microscope is usually designed as a thin cylinder. A sample is placed on the sample table, a reverse electric field is added through the sample table, so that signal electrons converge and are efficiently detected by the coaxial electronic detector. This requires a uniform electric field, i.e. the sample is very flat, the area of the bottom of the objective lens is as large as possible, and the installation of other devices in the sample chamber is also limited by the uniformity of the electric field.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a sample platform and have scanning electron microscope of this sample platform with ellipsoid speculum at least to convergence through the ellipsoid speculum improves coaxial electron detector's detection efficiency.

In order to achieve the above purpose, the utility model provides a following technical scheme:

in a first aspect, the utility model provides a sample platform with ellipsoid speculum, including sample platform body and the upwards ellipsoid speculum of speculum face, the bottom of ellipsoid speculum is followed sample platform body all around with this body coupling of sample platform, the downside focus of ellipsoid speculum is located on the loading end of sample platform body.

Preferably, a gold plating layer is arranged on the reflecting surface of the ellipsoidal reflector.

Preferably, the thickness of the gold-plated layer is 0.3-0.6 microns.

In a second aspect, the utility model provides a scanning electron microscope, including sample platform and coaxial electron detector, the sample platform is aforementioned arbitrary sample platform, coaxial electron detector sets up the below of the upside focus of ellipsoid shape speculum.

Preferably, the orthographic projection of the effective detection area of the coaxial electronic detector coincides with the orthographic projection of the top opening of the ellipsoidal reflector.

Optionally, the in-line electron detector is located within a column of the scanning electron microscope.

Optionally, the in-line electron detector is located outside a barrel of the scanning electron microscope.

Optionally, the in-line electron detector is located below a lens barrel of the scanning electron microscope.

The utility model provides a have sample platform of ellipsoidal speculum and have this sample platform's scanning electron microscope, utilize light or electron that ellipsoidal speculum had from one of them focus transmission can be in the characteristic that another focus converged, converge the signal electron that surpasss coaxial electron detector and survey the size, make it survey the size internal reflection to coaxial electron detector, improve coaxial electron detector's detection efficiency to can replace the scheme that adds reverse electric field at the sample platform.

The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments thereof, taken in conjunction with the accompanying drawings.

Drawings

Some specific embodiments of the present invention will be described in detail hereinafter, by way of illustration and not by way of limitation, with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:

FIG. 1 is a schematic cross-sectional view of a sample stage with an ellipsoidal reflector according to an embodiment of the present invention;

fig. 2 is a schematic cross-sectional view of a sample stage with an ellipsoidal reflector according to another embodiment of the present invention.

Reference numerals:

1-incident electron beam; 2-an objective lens; 3-a sample stage with an ellipsoidal reflector; 31-sample stage body; 32-ellipsoidal mirrors; 4-sample; 5-signal electrons; 6-coaxial electronic detector.

Detailed Description

It should be noted that, in the present invention, the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

The scanning electron microscope mainly comprises the following components:

an electron optical system comprising an electron gun and a lens system. The electron gun functions to generate an electron illumination source. The lens system is used for (1) reducing the size of virtual light source from tens of micrometers to 5nm (or less) and continuously changing from tens of micrometers to several nanometers, (2) controlling the opening angle of electron beam, which can be 10% ^-2 ～10 ^-3 The rad is variable, and (3) the resulting focused electron beam can be scanned raster-like over the surface of the sample, with a variable scanning angle, in order to obtain the above-mentioned scanning electron beam, the lens system usually comprises an electromagnetic lens and a scanning coil, the scanning coil serving to deflect the electron beam and to perform a regular sweep over the surface of the sample.

A mechanical system comprising a support portion and a sample chamber. The sample chamber is provided with a sample platform, and the four walls are generally provided with a plurality of windows, so that the electronic detector can be installed, and other detectors and spectrometers can be installed at the same time.

Vacuum systems, which are important in electron-optical instruments, are because electron beams can only be generated and manipulated under vacuum. The commonly used high vacuum systems include three types, namely a dry pump system, a turbomolecular pump system and an ion pump system.

In the signal collecting, processing and displaying system, an electron beam emitted by an electron gun of a scanning electron microscope is focused and then converged into a point light source, the point light source forms a high-energy electron beam under an accelerating voltage, the high-energy electron beam is focused into a light spot with a small diameter through an electromagnetic lens, after passing through an electromagnetic lens with a scanning coil at the last stage, the electron beam bombards the surface of a sample point by point in a raster scanning mode, and physical signals with different depths are excited simultaneously. The physical signals can be received by different signal detectors and synchronously transmitted to a computer display screen through an amplifier to form real-time imaging record. The sample generates various physical signals under the action of incident electron beams, such as auger electrons (Au E), Secondary Electrons (SE), backscattered electrons (BSE), X-rays (characteristic X-rays, continuous X-rays), Cathodoluminescence (CL), Absorbed Electrons (AE) and transmitted electrons, and different physical signals are detected by different types of detection systems. There are roughly three main categories, namely electron detectors, cathodoluminescence detectors and X-ray detectors.

The electron optical system is generally located in a lens barrel above the sample chamber, the signal detector is generally located in the sample chamber or the lens barrel, the electron gun, the lens system, the signal detector and the like are connected with an external power supply, and the vacuum system provides a vacuum environment for the lens barrel and the sample chamber.

In order to reach the purpose that improves detection efficiency, the utility model provides a sample platform with ellipsoid speculum utilizes the light or the electron that light or electron that one of them focus emission that ellipsoid speculum had to converge at another focus, to exceeding the signal electron that coaxial electron detector surveyed the size, makes it survey the size internal reflection to coaxial electron detector, improves coaxial electron detector's detection efficiency to can replace the scheme that adds reverse electric field at the sample platform.

Fig. 1 shows a specific embodiment of the present invention. As shown in fig. 1, the sample stage 3 with the ellipsoidal reflector of the present invention includes a sample stage body 31 and an ellipsoidal reflector 32 with a reflective surface facing upward. The bottom of the ellipsoidal reflector 32 is connected with the sample stage body 31 along the periphery of the sample stage body 31, and the lower side focus of the ellipsoidal reflector 32 is positioned on the bearing surface of the sample stage body 31.

In this embodiment, the coaxial electronic probe 6 is located inside a lens barrel (not shown). In this embodiment, it is preferable that the orthographic projection of the effective detection area of the coaxial electronic detector 6 coincides with the orthographic projection of the top opening of the ellipsoidal mirror 32. When the sample stage 3 with the ellipsoidal reflector of the present invention is used in a scanning electron microscope, the coaxial electron detector 6 is disposed below the upper focus of the ellipsoidal reflector 32. An incident electron beam 1 emitted from an electron gun (not shown in the figure) hits a sample 4 generating signal electrons 5, which signal electrons 5 are emitted in various directions (180 °). A part of the signal electrons 5 will be directly detected by the coaxial electron detector 6, and at least a part of the signal electrons 5 with a larger exit angle will be reflected by the ellipsoidal mirror 32, converge towards the upper part of the coaxial electron detector 6, and be detected by the effective detection area of the coaxial electron detector 6. The detection efficiency in this embodiment can be up to about 65% by simulation with ZEMAX.

In order to improve the reflection efficiency, a gold plating layer is further disposed on the reflection surface of the ellipsoidal reflector 32 in this embodiment, and the thickness is preferably 0.3 to 0.6 micrometers, and 0.4 micrometers is taken as an example in this embodiment. Since gold is very stable, the signal electrons 5 will be almost totally reflected by hitting the gold-plated layer, and even if there are a small amount of regenerated electrons, their main direction is nearly symmetrical with the incident direction about the normal to the plane (i.e., similar to reflection), so that the reflection efficiency of the ellipsoidal mirror 32 can be further improved.

Fig. 2 shows another embodiment of the present invention, which is different from the previous embodiment in that the coaxial electronic detector 6 is located outside the lens barrel (not shown in the figure), and in this embodiment, is specifically located below the lens barrel. The detection efficiency in this embodiment can be up to about 95% by simulation with ZEMAX.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (8)

1. The utility model provides a sample platform with ellipsoid shape speculum which characterized in that:

the sample stage comprises a sample stage body and an ellipsoidal reflector with a reflecting surface facing upwards, wherein the bottom of the ellipsoidal reflector is connected with the sample stage body along the periphery of the sample stage body, and a lower side focus of the ellipsoidal reflector is positioned on a bearing surface of the sample stage body.

2. The sample stage with ellipsoidal reflector of claim 1, wherein:

and a gold-plated layer is arranged on the reflecting surface of the ellipsoidal reflector.

3. The sample stage with ellipsoidal reflector of claim 2, wherein:

the thickness of the gold-plated layer is 0.3-0.6 microns.

4. A scanning electron microscope comprises a sample stage and a coaxial electron detector, and is characterized in that:

the sample stage according to any one of claims 1 to 3, wherein the coaxial electronic detector is arranged below the upper focus of the ellipsoidal reflector.

5. The scanning electron microscope of claim 4, wherein:

and the orthographic projection of the effective detection area of the coaxial electronic detector is superposed with the orthographic projection of the opening at the top of the ellipsoidal reflector.

6. The scanning electron microscope of claim 4, wherein:

the coaxial electron detector is positioned in a lens barrel of the scanning electron microscope.

7. The scanning electron microscope of claim 4, wherein:

the coaxial electron detector is positioned outside the lens barrel of the scanning electron microscope.

8. The scanning electron microscope of claim 7, wherein:

the coaxial electron detector is positioned below a lens cone of the scanning electron microscope.

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