CN217084755U

CN217084755U - Coaxial electron detector with ellipsoidal reflector and scanning electron microscope

Info

Publication number: CN217084755U
Application number: CN202220574170.0U
Authority: CN
Inventors: 杨润潇; 张松涛; 李晓昂
Original assignee: Huiran Technology Co ltd
Current assignee: Huiran Technology Co ltd
Priority date: 2022-03-16
Filing date: 2022-03-16
Publication date: 2022-07-29
Anticipated expiration: 2032-03-16

Abstract

The utility model discloses a coaxial electron detector and have scanning electron microscope of this coaxial detector with ellipsoid reflector, including coaxial electron detector body and ellipsoid reflector, the ellipsoid reflector includes tray and ellipsoid reflector, the tray has the centre bore, the top of ellipsoid reflector is followed all around of centre bore with the bottom of tray is connected, the tray top is located the below of the upside focus of ellipsoid reflector, coaxial electron detector body is located the top of tray. The utility model discloses increase the ellipsoidal reflector on current coaxial electronic detector's basis, utilize light or electron that ellipsoidal reflector had from one of them focus transmission can converge at another focus characteristic, converge the signal electron that surpasss coaxial electronic detector and survey the size, make it survey the size internal reflection to coaxial electronic detector, improved coaxial electronic detector's detection efficiency greatly.

Description

Coaxial electron detector with ellipsoidal reflector and scanning electron microscope

Technical Field

The utility model relates to a scanning electron microscope technical field especially relates to a coaxial electron detector and have scanning electron microscope of this coaxial electron detector with ellipsoid reflector.

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 scattered electrons and the like in physical signals in a scanning electron microscope, wherein the coaxial electronic 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 scattered electrons reflected towards the lens barrel.

At present, most electron microscope manufacturers in China cannot produce the coaxial electronic detectors by themselves and can only purchase the coaxial electronic detectors from other suppliers, so that the sizes of the coaxial electronic detectors cannot be flexibly selected according to the placement positions and the electronic optical systems, and the detection efficiency of the detectors is greatly limited.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a coaxial electron detector and have scanning electron microscope of this coaxial electron detector with ellipsoid reflector at least to improve 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 coaxial electronic detector with ellipsoid reflector, including coaxial electronic detector body and ellipsoid reflector, the ellipsoid reflector includes tray and the ellipsoid reflector of speculum face down, the tray has the centre bore, the top of ellipsoid reflector is followed all around of centre bore with the bottom of tray is connected, the tray top is located the below of the upside focus of ellipsoid reflector, coaxial electronic detector body is located the top of tray.

Preferably, the top of the ellipsoidal reflector is connected to the bottom of the tray along the edge of the central hole.

Preferably, the orthographic projection of the central hole coincides with the orthographic projection of the effective detection area of the coaxial electronic detector body.

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

Optionally, the thickness of the gold plating layer is 0.3-0.6 microns.

In a second aspect, the present invention provides a scanning electron microscope, including any one of the aforementioned coaxial electron detectors with an ellipsoidal reflector, wherein the lower focal point of the ellipsoidal reflector is located on the bearing surface of the sample stage of the scanning electron microscope.

Optionally, the coaxial electron detector with the ellipsoidal reflector is located within a column of the scanning electron microscope.

Optionally, the coaxial electron detector with the ellipsoidal reflector is located outside a lens barrel of the scanning electron microscope.

The utility model provides a coaxial electron detector with ellipsoid reflector and have scanning electron microscope of this coaxial detector increases the ellipsoid reflector on current coaxial electron detector's basis, utilize light or the electron that ellipsoid speculum had from one of them focus transmission can be in the characteristic that another focus was converged, converge the signal electron that surpasss coaxial electron detector detection size, make it survey the size internal reflection to coaxial electron detector, coaxial electron detector's detection efficiency has been improved greatly.

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 diagram of a cross-sectional structure of a coaxial electronic probe with an ellipsoidal reflector according to an embodiment of the present invention.

Reference numerals:

1-incident electron beam; 2-a coaxial electronic probe body; 3-an objective lens; 4-sample; 5-an ellipsoidal reflector; 51-a tray; 52-ellipsoidal reflectors; 53-central hole; 6-signal electrons.

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. Under the action of incident electron beams, the sample can generate various physical signals, namely auger electrons (Au E), Secondary Electrons (SE), backscattered electrons (BSE), X rays (characteristic X rays and continuous X rays), cathode fluorescence (CL), Absorbed Electrons (AE) and transmitted electrons, and different physical signals need 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 achieve the purpose of improving the detection efficiency, the utility model discloses increase the ellipsoidal reflector on current coaxial electronic detector's basis, utilize the light or the electron that the ellipsoidal reflector had from one of them focus transmission can converge at another focus characteristic, converge the signal electron that surpasss coaxial electronic detector and survey the size, make it survey the size internal reflection to coaxial electronic detector, improve coaxial electronic detector's detection efficiency.

Fig. 1 shows a specific embodiment of the present invention. As shown in fig. 1, the coaxial electronic probe with ellipsoidal reflector of the present invention includes a coaxial electronic probe body 2 and an ellipsoidal reflector 5. The coaxial electronic detector 2 is located inside a lens barrel (not shown) or outside the lens barrel, for example below the lens barrel. The ellipsoidal reflector 5 comprises a tray 51 and an ellipsoidal reflector 52 with the reflective surface facing downwards, the tray 51 having a central hole 53, the top of the ellipsoidal reflector 52 being connected to the bottom of the tray 51 along the periphery of the central hole 53, preferably the top of the ellipsoidal reflector 52 being connected to the bottom of the tray 51 along the edge of the central hole 53. The top of the tray 51 is located below the upper focal point of the ellipsoidal reflector 52, the coaxial electronic detector body 2 is located on the top of the tray 51, and preferably the orthographic projection of the central hole 53 coincides with the orthographic projection of the effective detection area of the coaxial electronic detector body 2.

As shown in fig. 1, when the coaxial electron probe with the ellipsoidal reflector of the present invention is used in a scanning electron microscope, the sample 4 is placed at the lower focal point of the ellipsoidal reflector 52, i.e., the lower focal point of the ellipsoidal reflector 52 is located on the bearing surface of the sample stage (not shown in the figure) of the scanning electron microscope. An incident electron beam 1 emitted from an electron gun (not shown in the figure) hits on a sample 4 to generate signal electrons 6, a part of the signal electrons 6 reflected from the sample 4 towards the lens barrel direction is directly detected by the coaxial electron detector body 2, and at least a part of the signal electrons 6 exceeding the effective detection area of the coaxial electron detector body 2 are reflected by the ellipsoidal mirror 52, converged towards the upper part of the coaxial electron detector body 2, and are detected by the effective detection area of the coaxial electron detector body 2. Simulation is carried out through ZEMAX, and the detection efficiency can reach 100% at most.

In order to improve the reflection efficiency, a gold plating layer is further disposed on the reflection surface of the ellipsoidal reflector 52 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 has excellent stability, the signal electrons 6 hit the gold-plated layer and are almost totally reflected, and even if there are a small amount of regenerated electrons, their principal directions are 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 52 can be further improved.

For the support and fixation of the coaxial electron detector body 2 and the ellipsoidal reflector 5, the embodiment is not particularly limited, and a suitable mode can be selected according to the overall design of the scanning electron microscope in practical application.

The above description is only a 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

1. The coaxial electronic detector with the ellipsoidal reflector is characterized by comprising a coaxial electronic detector body and the ellipsoidal reflector, wherein the ellipsoidal reflector comprises a tray and an ellipsoidal reflector with a downward reflecting surface, the tray is provided with a central hole, the periphery of the central hole is connected with the bottom of the tray along the top of the ellipsoidal reflector, the top of the tray is positioned below an upper side focus of the ellipsoidal reflector, and the coaxial electronic detector body is positioned at the top of the tray.

2. The coaxial electronic probe with an ellipsoidal reflector of claim 1, wherein the top of the ellipsoidal reflector is attached to the bottom of the tray along the edge of the central hole.

3. The coaxial electronic probe with the ellipsoidal reflector of claim 1, wherein an orthographic projection of the central aperture coincides with an orthographic projection of an effective detection area of the coaxial electronic probe body.

4. The coaxial electronic detector with an ellipsoidal reflector of claim 1, wherein the reflecting surface of the ellipsoidal reflector is provided with a gold plating.

5. The coaxial electronic detector with an ellipsoidal reflector of claim 4, wherein the gold plating layer has a thickness of 0.3 to 0.6 μm.

6. A scanning electron microscope comprising the in-line electron probe with an ellipsoidal reflector according to any one of claims 1 to 5, wherein the lower focal point of the ellipsoidal reflector is located on the bearing surface of a sample stage of the scanning electron microscope.

7. The SEM according to claim 6, wherein the in-line electron detector with the ellipsoidal reflector is located within a column of the SEM.

8. The SEM according to claim 6, wherein the coaxial electron detector with the ellipsoidal reflector is located outside a lens barrel of the SEM.