CN215812515U - Electronic detector - Google Patents

Abstract

The application discloses an electronic detector (10), including: a scintillator (120); an optical lens group (130) disposed at a rear side of the scintillator (120); and a photomultiplier tube (150) disposed behind the optical lens group (130), wherein the scintillator (120) is configured to receive bombarded emitted photons of the electrons; the optical lens group (130) is composed of at least one optical lens (131), and the optical lens group (130) is used for projecting photons to the photomultiplier tube (150).

Description

Electronic detector

Technical Field

The present application relates to the field of electron microscopy, and more particularly, to an electron detector.

Background

Electron microscopes are important scientific instruments and play a great role in the fields of material science, life science, semiconductor industry, and the like. The scanning electron microscope scans a sample by using a focused high-energy electron beam, and in the scanning process, the purposes of substance microscopic morphology characterization and component characterization are achieved by collecting secondary electrons generated by interaction of incident electrons and the sample, backscattered electrons and other electronic information containing the surface morphology and components of the sample. In order to improve the signal-to-noise ratio of the image, the collection efficiency of signal electrons, the electron-photon conversion efficiency, and the photon conduction efficiency should be improved as much as possible. The existing electronic detector consists of an electronic collecting net, a scintillator, a light guide tube, a photomultiplier and an amplifying circuit, and the following signal loss behaviors usually exist in the process of collecting electronic signals: 1. the photons are refracted for multiple times in the scintillator and absorbed; 2. the photons are reflected back to the inside of the scintillator at the scintillator emergent surface; 3. the photons exit the scintillator side wall; 4. photons are absorbed inside the light pipe; 5. the photons are reflected back into the light pipe at the exit surface of the light pipe; 6. photons are reflected at the incidence surface of the photomultiplier; the exit angle of the 7 photons on the exit surface of the light guide pipe is too large, and the photons do not completely enter the photomultiplier.

Aiming at the technical problem that the signal-to-noise ratio of an image is reduced due to signal loss in the process of collecting an electronic signal to form the image by the existing electronic detector in the prior art, and further the image quality is influenced, an effective solution is not provided at present.

SUMMERY OF THE UTILITY MODEL

The utility model provides an electronic detector, which at least solves the technical problem that the signal-to-noise ratio of an image is reduced due to signal loss in the process of collecting electronic signals to form the image in the prior art, so that the image quality is influenced.

According to an aspect of the present application, there is provided an electronic detector comprising: a scintillator; an optical lens group disposed at a rear side of the scintillator; and a photomultiplier tube disposed behind the optical lens group, wherein the scintillator is configured to receive bombarded emitted photons of the electrons; the optical lens group is composed of at least one optical lens, and the optical lens group is used for projecting photons to the photomultiplier tube.

Optionally, the incident surface and/or the exit surface of the optical lens is provided with an antireflection film.

Optionally, an antireflection film is disposed on the exit surface of the scintillator.

Optionally, the method further comprises: an electron collection mesh disposed on a front side of the scintillator and configured to attract electrons.

Optionally, the method further comprises: and the vacuum window is arranged in the middle of the optical lens group and the photomultiplier, an antireflection film is arranged on two sides of the vacuum window, and the vacuum window is used for realizing vacuum sealing between the optical lens group and the photomultiplier.

Optionally, the method further comprises: and the flange is arranged on the back side surface of the photomultiplier, is a high-voltage lead flange and is configured to introduce voltage into a vacuum chamber on the front side of the electron detector.

Optionally, the method further comprises: a scintillator holder of electrically conductive material configured to hold a scintillator.

Optionally, the method further comprises: an optical lens group holder made of insulating material is configured to hold an optical lens group.

Therefore, through the electronic detector provided by the application, the optical lens group replaces the traditional light guide pipe to greatly reduce the signal loss of photons in the transmission process, the approximate lossless transmission of the photons is achieved, and the technical effect of improving the image quality is achieved. And an antireflection film is arranged on the incident surface and/or the emergent surface of the optical lens and the antireflection film is arranged on the emergent surface of the scintillator, so that the transmission loss of photons is reduced, the signal loss of the photons is further reduced, and the technical effect of improving the image quality is achieved. And the technical problem that the signal-to-noise ratio of the image is reduced due to signal loss in the process of collecting the electronic signal to form the image by the existing electronic detector in the prior art, and the image quality is further influenced is solved. The incident angle of the light beam at the incident window of the photomultiplier can be adjusted by adjusting the light path and the magnification of the optical lens group, so that the aim of better matching the photomultiplier is fulfilled, the incident photon proportion is improved, and the integral magnification is improved.

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 application will be described in detail hereinafter by way of illustration and not 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 an electronic detector according to an embodiment of the present application; and

FIG. 2 is a schematic diagram of an electron detector collecting and transmitting electrons according to an embodiment of the present application.

Detailed Description

It should be noted that 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 embodiments with reference to the attached drawings.

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances for describing embodiments of the utility model herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

FIG. 1 is a schematic diagram of an electronic detector 10 according to an embodiment of the present application. Referring to fig. 1, an electron probe 10 includes: a scintillator 120; an optical lens group 130 disposed at a rear side of the scintillator 120; and a photomultiplier tube 150 disposed behind the optical lens group 130, wherein the scintillator 120 is configured to receive bombarded emitted photons of electrons; the optical lens group 130 is composed of at least one optical lens 131, and the optical lens group 130 is used to project photons to the photomultiplier tube 150.

As described in the background, the existing electron detector is composed of an electron collecting net, a scintillator, a light guide, a photomultiplier tube and an amplifying circuit, and the following signal loss behaviors are generally present in the process of collecting the electron signals: 1. the photons are refracted for multiple times in the scintillator and absorbed; 2. the photons are reflected back to the inside of the scintillator at the scintillator emergent surface; 3. the photons exit the scintillator side wall; 4. photons are absorbed inside the light pipe; 5. the photons are reflected back into the light pipe at the exit surface of the light pipe; 6. photons are reflected at the incidence surface of the photomultiplier; the exit angle of the 7 photons on the exit surface of the light guide pipe is too large, and the photons do not completely enter the photomultiplier.

In view of this, fig. 2 shows a schematic diagram of the electron detector 10 for collecting and transmitting electrons, and referring to fig. 1 and 2, the embodiment of the present application provides an electron detector 10 including a scintillator 120, an optical lens group 130, and a photomultiplier tube 150. The scintillator 120 is added with 8-10 kV positive voltage to improve the energy of signal electrons, so that photons can be generated after the bombardment of the high-energy electrons. The generated photons are then sent through the optical lens group 130 to the photomultiplier tube 150. Wherein the magnification of the optical lens assembly 130 can be adjusted, and the optical lens assembly 130 can be used to replace the light pipe to converge or diverge the photons emitted from the scintillator 120. Therefore, the size of the light spot incident on the window of the photomultiplier tube 150 and the incident angle can be adjusted by the optical lens group 130. So that the incident photons satisfy the optimal operating conditions of the photomultiplier tube. Finally, the photomultiplier tube 150 may convert the incident photons into electrons, and then amplify the electrons several tens of thousands to several hundreds of thousands of times in stages.

Therefore, through the electronic detector 10 provided by the present application, the optical lens group 130 is used to replace the conventional light pipe, so as to avoid signal loss of photons in the transmission process, achieve the technical effects of lossless propagation of photons and improving image quality. And the technical problem that the signal-to-noise ratio of the image is reduced due to signal loss in the process of collecting the electronic signal to form the image by the existing electronic detector in the prior art, and the image quality is further influenced is solved.

In addition, by adjusting the optical path and the magnification of the optical lens assembly 130, the incident angle of the light beam at the incident window of the photomultiplier tube 150 can be adjusted, so as to achieve the purpose of better matching the photomultiplier tube 150, thereby improving the proportion of incident photons and the overall magnification.

In addition, the present application provides an electron detector 10 suitable for use in an electron microscope system.

Alternatively, as shown in fig. 2, the incident surface and/or the exit surface of the optical lens 131 is provided with an antireflection film. The antireflection film is arranged on the incident surface and/or the emergent surface of the optical lens 131, so that the transmittance of photons is increased, the photons are prevented from being reflected back on the incident surface and the emergent surface to cause signal loss of the photons, and the technical effect of increasing the image quality is achieved. And the technical problem that the signal-to-noise ratio of the image is reduced due to signal loss in the process of collecting the electronic signal to form the image by the existing electronic detector in the prior art, and the image quality is further influenced is solved.

Alternatively, as shown in fig. 1, the exit surface of the scintillator 120 is provided with an antireflection film. The anti-reflection film is arranged on the emergent surface of the scintillator 120, so that the transmittance of photons is increased, and the photons are prevented from being refracted for multiple times and absorbed in the scintillator 120. The nondestructive transmission of photons is realized, and the technical effect of increasing the image quality is achieved.

Optionally, as shown with reference to fig. 1, the electronic detector 10 further comprises: an electron collecting mesh 110 disposed at the front side of the scintillator 120 is configured to attract electrons. Wherein a positive voltage of 100-300v is applied to the surface of the electron collecting mesh 110 so as to attract electrons.

Optionally, as shown with reference to fig. 1, the electronic detector 10 further comprises: and a vacuum window 140 disposed at a middle position between the optical lens group 130 and the photomultiplier tube 150, wherein both sides of the vacuum window 140 are provided with an antireflection film, and the vacuum window 140 is used to achieve vacuum sealing between the optical lens group 130 and the photomultiplier tube 150. Wherein the vacuum window 140 is coated with anti-reflection coating on both sides of the high transmittance material to allow light to pass therethrough while isolating vacuum. And photons penetrate through the vacuum window 140 and enter the photomultiplier 150, so that physical contact is avoided, and the system installation of the electronic detector 10 in a complex environment is facilitated.

Optionally, as shown with reference to fig. 1, the electronic detector 10 further comprises: a flange 160 disposed on the back side of the photomultiplier tube 150, wherein the flange 160 is a high voltage lead flange configured to introduce a voltage into the vacuum chamber 190 on the front side of the electron detector 10. Among them, the electron collecting grid 110, the scintillator 120 and the optical lens group 130 in the electron detector 10 are disposed in a vacuum environment, and therefore a vacuum chamber 190 is disposed around the electron collecting grid 110, the scintillator 120 and the optical lens group 130. So that the positive high pressure required by the electron collection grid 110 and the scintillator 120 can be introduced into the vacuum chamber 190 through the high pressure lead flange 160. The technical effect of providing positive high voltage for the electron collecting grid 110 and the scintillator 120 is achieved.

Optionally, as shown with reference to fig. 1, the electronic detector 10 further comprises: the scintillator holder 170 of a conductive material is configured to hold the scintillator 120. The scintillator holder 170 may be made of a metal conductive material, so that the technical effect of stabilizing the scintillator 120 by the scintillator holder 170 is achieved.

Optionally, as shown with reference to fig. 1, the electronic detector 10 further comprises: an optical lens group holder 180 made of an insulating material is configured to hold the optical lens group 130. The optical lens assembly holder 180 may be made of a ceramic insulating material, so that the optical lens assembly holder 180 can stabilize the optical lens assembly 130.

Therefore, through the electronic detector 10 provided by the present application, the optical lens group 130 is used to replace the conventional light pipe, so as to avoid signal loss of photons in the transmission process, achieve the technical effects of lossless propagation of photons and improving image quality. And an antireflection film is arranged on the incident surface and/or the emergent surface of the optical lens 131 and an antireflection film is arranged on the emergent surface of the scintillator 120, so that the nondestructive transmission of photons is further achieved, the signal loss of the photons is avoided, and the technical effect of increasing the image quality is achieved. And the technical problem that the signal-to-noise ratio of the image is reduced due to signal loss in the process of collecting the electronic signal to form the image by the existing electronic detector in the prior art, and the image quality is further influenced is solved. In addition, by adjusting the optical path and the magnification of the optical lens assembly 130, the incident angle of the light beam at the incident window of the photomultiplier tube 150 can be adjusted, so as to achieve the purpose of better matching the photomultiplier tube 150, thereby improving the proportion of incident photons and the overall magnification.

In addition, in a typical scanning electron microscope system, an electron detector is usually used to collect an electron signal, and during the process, the scanning position and the collected electron signal are synchronized to constitute a microscopic image of the local part of the scanned sample. The structure is as follows:

1. the electron collecting net 110 is added with a voltage of-100-500V and used for attracting electrons, and the additional voltage of the electron collecting net 110 can be a voltage capable of attracting electrons in other ranges;

2. the scintillator 120 is added with 8-10 kV positive voltage to improve signal electron energy, photons can be generated after bombardment of high-energy electrons, and in addition, other voltages capable of providing electron capability can be added to the scintillator to generate photons;

3. an optical lens group 130 for converging or diverging the photons generated by the scintillator 120, and adjusting the size and the incident angle of the light spot incident on the photomultiplier tube 150;

4. the vacuum window 140 is made of a high-transmittance material with antireflection films coated on both sides, and allows light to pass through while isolating vacuum;

5. the photomultiplier 150 converts photons into electrons, and magnifies the electrons several tens of thousands to several hundreds of thousands of times step by step;

6. a high-pressure lead flange 160 for introducing two positive high pressures required by the electron collecting net 110 and the scintillator 120 into the vacuum chamber;

7. a scintillator holder 170, a metal conductive material;

8. lens group fixer 180, ceramic insulating material.

The system improves the processes of electron collection and photon transmission and improves the image signal-to-noise ratio. The specific implementation mode is as follows:

1. plating an antireflection film on the emergent surface of the scintillator 120;

2. the light guide pipe is eliminated, and absorption loss of photons in the light guide pipe is avoided;

3. the light pipe is replaced by an optical lens group 130, and the light emitted by the scintillator can be converged or diverged. Thus, the spot size and angle of incidence on the window of the photomultiplier tube 150 may be adjusted. So that the incident light meets the optimal operating conditions of the photomultiplier tube 150;

4. light rays penetrate through the vacuum window 140 and enter the photomultiplier 150, so that physical contact is avoided, and system installation under complex environments is facilitated.

Thus, the application has the following innovation points:

1. a scintillator 120 with an antireflection film on the exit surface;

2. an optical lens group 130 of one lens or a plurality of lenses replaces the traditional light guide;

3. the magnification of optical lens group 130 is adjustable;

4. the optical lens group 130 can be used to change the size of the light spot incident on the window of the photomultiplier tube 150 and the incident angle;

5. an optical lens group 130 with antireflection coating on both the incident surface and the exit surface;

6. the vacuum window 140 has a double-sided total reflection film.

The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

In the description of the present invention, it is to be understood that the orientation or positional relationship indicated by the orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc. are usually based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and in the case of not making a reverse description, these orientation words do not indicate and imply that the device or element being referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore, should not be considered as limiting the scope of the present invention; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

The above description is only for the preferred embodiment of the present application, but the scope of the present application 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 application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (8)

1. An electronic detector (10), comprising: a scintillator (120); an optical lens group (130) disposed at a rear side of the scintillator (120); and a photomultiplier tube (150) disposed at a rear side of the optical lens group (130), wherein

The scintillator (120) is used for receiving bombardment emission photons of electrons;

the optical lens group (130) is composed of at least one optical lens (131), and the optical lens group (130) is used for projecting the photons to the photomultiplier tube (150).

2. The electron detector (10) according to claim 1, characterized in that the entrance face and/or the exit face of the optical lens (131) is provided with an antireflection film.

3. The electron detector (10) of claim 1, wherein the exit face of the scintillator (120) is provided with an antireflection coating.

4. The electronic detector (10) of claim 1, further comprising: an electron collecting mesh (110) disposed in front of the scintillator (120) and configured to attract the electrons.

5. The electronic detector (10) of claim 1, further comprising: a vacuum window (140) disposed at an intermediate position between the optical lens group (130) and the photomultiplier tube (150), wherein an antireflection film is disposed on an incident surface and/or an exit surface of the vacuum window (140), and

the vacuum window (140) is used to achieve a vacuum seal between the optical lens group (130) and the photomultiplier tube (150).

6. The electronic detector (10) of claim 1, further comprising: a flange (160) disposed at a rear side of the photomultiplier tube (150), wherein

The flange (160) is a high voltage lead flange configured for introducing a voltage into a vacuum chamber (190) at the front side of the electronic detector (10).

7. The electronic detector (10) of claim 1, further comprising: a scintillator holder (170) of an electrically conductive material configured to hold the scintillator (120).

8. The electronic detector (10) of claim 1, further comprising: an optical lens group holder (180) made of an insulating material and configured to hold the optical lens group (130).

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