CN218069773U

CN218069773U - Diaphragm with prefocusing structure and scanning electron microscope

Info

Publication number: CN218069773U
Application number: CN202220796937.4U
Authority: CN
Inventors: 杨润潇; 杨思源
Original assignee: Huiran Technology Co ltd
Current assignee: Huiran Technology Co ltd
Priority date: 2022-04-07
Filing date: 2022-04-07
Publication date: 2022-12-16
Anticipated expiration: 2032-04-07

Abstract

The utility model discloses a diaphragm and scanning electron microscope with pre-focusing structure, this diaphragm includes insulating substrate, be provided with the center through-hole that link up upper surface and lower surface and distribute in a plurality of pre-focusing through-holes around the center through-hole on the insulating substrate, pre-focusing through-hole inclines to center through-hole direction, and the radial minimum distance between the central line of the central through-hole and the lower drill way circumference of pre-focusing through-hole is greater than or equal to the radial maximum distance between the central line of central through-hole and the lower drill way circumference of pre-focusing through-hole; and at least the upper surface of the insulating substrate and the hole walls of the central through hole and the pre-focusing through hole are plated with metal layers. The utility model provides a diaphragm with prefocus structure through the directive property restraint of prefocus through-hole, can carry out the prefocus to the electron beam when realizing sheltering from stray electron, can reduce electromagnetic lens's use, saves the space of electron optics light path.

Description

Diaphragm with prefocusing structure and scanning electron microscope

Technical Field

The utility model relates to a scanning electron microscope technical field especially relates to a scanning electron microscope with diaphragm of prefocus structure and have this diaphragm.

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 diaphragm is a component of an electron optical system, and mainly has the functions of filtering the far-axis electrons in the electron beam, reducing the spherical aberration influence of the electron lens, adjusting the depth of field of an image and the like. Generally, electrons passing through the aperture have a relatively large divergence, and a series of electromagnetic lenses are often required to be matched to obtain a small-sized and high-quality electron beam.

SUMMERY OF THE UTILITY MODEL

It is an object of the present invention to provide a diaphragm with a prefocusing structure and a scanning electron microscope having the diaphragm to reduce the divergence of the electrons passing through the diaphragm.

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

in a first aspect, the present invention provides a diaphragm with a pre-focusing structure, including an insulating substrate, the insulating substrate includes an upper surface and a lower surface, the insulating substrate is provided with a central through hole penetrating the upper surface and the lower surface and a plurality of pre-focusing through holes distributed around the central through hole, the pre-focusing through hole is inclined toward the central through hole, and a radial minimum distance between an upper orifice circumference of the pre-focusing through hole and a center line of the central through hole is greater than or equal to a radial maximum distance between a lower orifice circumference of the pre-focusing through hole and the center line of the central through hole; and at least the upper surface of the insulating substrate and the hole walls of the central through hole and the pre-focusing through hole are plated with metal layers.

Optionally, several circles of the pre-focusing through holes are distributed around the central through hole at the same interval.

Optionally, the pre-focusing through holes in each circle are uniformly distributed.

Optionally, the metal layer is a gold layer or a platinum layer.

Optionally, the insulating matrix is an intrinsic silicon matrix.

Optionally, the insulating substrate is disc-shaped.

Optionally, an inner wall surface of the pre-focusing through hole, which receives the incident electrons, is a parabolic reflecting surface.

Optionally, the focus of the parabolic reflecting surface of all the pre-focusing through holes is located at the same point on the center line of the central through hole.

Optionally, the tilt angle of the pre-focus via is larger the further away from the central through via.

In a second aspect, the present invention provides a scanning electron microscope, comprising any one of the above diaphragms with a pre-focusing structure.

The utility model provides a diaphragm with prefocus structure through the directive property restraint of prefocus through-hole, can carry out the prefocus to the electron beam when realizing sheltering from stray electron, can reduce electromagnetic lens's use, saves the space of electron optics light path.

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 invention will be described in detail hereinafter by way of example 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 top view of a diaphragm with a pre-focusing structure according to an embodiment of the present invention;

FIG. 2 is a schematic perspective cross-sectional view of the diaphragm shown in FIG. 1 having a pre-focusing structure;

FIG. 3 is a schematic front cross-sectional view of the diaphragm shown in FIG. 1 having a pre-focusing structure.

Reference numerals are as follows:

1-an insulating matrix; 2-a central through-hole; 3-prefocusing through hole

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 can be continuously changed from tens of micrometers to several nanometers, (2) controlling the opening angle of electron beam, and can be in 10 deg.C ^-2 ～10 ^-3 The rad is variable, and (3) the formed focused electron beam can be scanned in a raster-like manner on the surface of the sample, and the scanning angle range is variable, in order to obtain the above-mentioned scanned electron beam, the lens system usually includes an electromagnetic lens, a scanning coil and a diaphragm, the electromagnetic lens is used for focusing the electron beam, the scanning coil is used for deflecting the electron beam and making regular scanning on the surface of the sample, and the diaphragm is used for filtering the far-axis electrons in the electron beam and adjusting the depth of field of the image.

A mechanical system comprising a support portion and a sample chamber. The sample chamber is provided with a sample stage, 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 tiny 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-shaped scanning mode, and simultaneously, physical signals with different depths are excited. 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.

For solving the great problem of electron beam divergence through the diaphragm among the prior art, the utility model provides a diaphragm with prefocus structure.

As shown in fig. 1-3, the utility model provides a diaphragm with prefocus structure includes insulating base 1, and insulating base 1 includes upper surface and lower surface, is provided with the straight-through-hole 2 in center that link up upper surface and lower surface on insulating base 1 and distributes in a plurality of prefocus through-holes 3 around the straight-through-hole 2 in center. The pre-focusing through hole 3 inclines towards the direction of the central through hole 2, and the radial minimum distance between the circumference of the orifice on the pre-focusing through hole 3 and the center line of the central through hole 2 is larger than or equal to the radial maximum distance between the circumference of the orifice under the pre-focusing through hole 3 and the center line of the central through hole 2, so that the projection of the upper orifice and the lower orifice in the vertical direction can be tangent or staggered, and electrons are prevented from directly passing through the pre-focusing through hole 3 without reflection, and the point can be realized by enabling the axial length of the pre-focusing through hole 3 to be larger than the diameter of the orifice. It should be noted here that, in order to avoid that basic structural features are difficult to show due to too large size difference (the axial length may be hundreds of times of the diameter of the orifice), the drawings 1 to 3 are not drawn according to actual size and proportion, and are drawn according to the real size proportion, so that through holes of micro-nano size level cannot be expressed. At least the upper surface of the insulating substrate 1 and the walls of the central through via 2 and the pre-focus via 3 are coated with a metal layer, preferably a stable metal such as gold or platinum. In this embodiment, the farther the pre-focusing through hole 3 from the center through hole 2 is, the larger the inclination angle is, so as to achieve a better pre-focusing effect.

In some embodiments, several circles of pre-focus vias 3 are distributed around the central through via 2 at the same pitch; in some embodiments, the pre-focusing through-holes 3 within each turn are evenly distributed.

In some embodiments, the inner wall surface of the pre-focusing via 3 receiving the incident electrons may be designed as a parabolic reflecting surface, and the focal points of the parabolic reflecting surfaces of all the pre-focusing vias 3 may be located at the same point on the center line of the central through via 2.

The following explains the manufacture of the diaphragm with the prefocusing structure by an example, a disc-shaped intrinsic silicon with a diameter of 3mm and a thickness of 0.5mm is used as an insulating substrate, and is processed on the insulating substrate by utilizing micro-nano processing technologies such as photoetching or electron beam/ion beam etching, and a central through hole with a diameter of 1 micron and a plurality of prefocusing through holes are carved, wherein the aperture of the prefocusing through holes can be the same as or different from that of the central through hole, and the aperture of the outer ring prefocusing through hole can be larger than that of the inner ring prefocusing through hole. And pre-coking, evaporating and plating gold, platinum and other stable metals on the upper surface or the whole outer surface of the insulating substrate and the wall surfaces of the central through hole and the pre-coking through hole.

When the diaphragm works, parallel electron beams downwards enter from the upper part of the diaphragm with the pre-focusing structure, electrons passing through the central through hole 2 directly pass through the diaphragm, all or part of the electrons passing through the pre-focusing through hole 3 are emitted towards the direction of the central through hole 2 through the reflection surface of the pre-focusing through hole 3, and the rest electrons are blocked by the upper surface of the insulating substrate 1, so that the pre-focusing of the electron beams is realized while stray electrons are blocked.

Therefore, the utility model provides a diaphragm with prefocus structure, directive property restraint through the prefocus through-hole can shelter from stray electron when carrying out the prefocus to the electron beam in the realization, can reduce electromagnetic lens's use, saves the space of electron optics light path.

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

1. A diaphragm with a pre-focusing structure is characterized by comprising an insulating substrate, wherein the insulating substrate comprises an upper surface and a lower surface, a central through hole penetrating through the upper surface and the lower surface and a plurality of pre-focusing through holes distributed around the central through hole are formed in the insulating substrate, the pre-focusing through holes are inclined towards the central through hole, and the radial minimum distance between the circumference of an upper orifice of each pre-focusing through hole and the center line of the central through hole is larger than or equal to the radial maximum distance between the circumference of a lower orifice of each pre-focusing through hole and the center line of the central through hole; and at least the upper surface of the insulating substrate and the hole walls of the central through hole and the pre-focusing through hole are plated with metal layers.

2. The diaphragm with the pre-focusing structure of claim 1, wherein a plurality of circles of the pre-focusing through holes are distributed around the central through hole at the same interval.

3. Diaphragm with a pre-focusing structure according to claim 2, characterized in that the pre-focusing through holes in each circle are evenly distributed.

4. The diaphragm with the pre-focusing structure according to claim 1, wherein the metal layer is a gold layer or a platinum layer.

5. The optical diaphragm with a pre-focusing structure of claim 1, wherein said insulating matrix is an intrinsic silicon matrix.

6. Diaphragm with a prefocusing structure according to claim 1, characterized in that said insulating matrix is disc-shaped.

7. The diaphragm with the pre-focusing structure according to claim 1, wherein the inner wall surface of the pre-focusing through hole receiving the incident electrons is a parabolic reflecting surface.

8. The optical diaphragm with a pre-focusing structure according to claim 7, wherein the focus points of the parabolic reflecting surfaces of all the pre-focusing through holes are located at the same point on the center line of the central through hole.

9. Light stop with a pre-focusing structure according to claim 1, characterized in that the tilt angle of the pre-focusing through hole is larger the farther away from the central through hole.

10. A scanning electron microscope comprising a diaphragm according to any one of claims 1 to 9 having a prefocusing structure.