Electron emission device, electron detection device and their combination

Abstract

The present invention discloses an electron emission device, an electron detection device and a combination thereof. The electron emission device includes an insulating substrate and a metal surface, the metal surface covering one side of the insulating substrate, and a plurality of filaments being constructed on one side of the metal surface, the plurality of filaments being arranged at intervals and having parallel extending directions. The electron detection device includes a plurality of isolation layers, a plurality of PN junctions, a plurality of electron receiving layers, a plurality of conductive columns and a plurality of lead-out layers. The electron emission device and the electron detection device provided by the present invention are in the form of multi-electron emission source emission and multi-detection point reception, and can realize the arrayed acquisition of sample images, improving the sampling throughput and detection efficiency. The combination of the electron emission device and the electron detection device can realize emission-detection integration, and the volume of the vacuum chamber occupied by such an integrated device is greatly reduced, which is conducive to promoting the miniaturization and portability of scanning electron microscopes, that is, creating conditions for the realization of portable scanning electron microscopes.

Description

Technical Field

[0001] The present invention relates to the technical field of scanning electron microscopes, and in particular, to an electron emission device, an electron detection device, and a combination thereof. Background Art

[0002] A scanning electron microscope (Scanning Electron Microscope, abbreviated as SEM), hereinafter referred to as a scanning electron microscope, is a commonly used microscopic analysis instrument that uses various physical signals excited when a focused electron beam scans the surface of a sample to modulate and form an image.

[0003] The electron beam is generated by an electron emission device. The electron emission device is a device that generates an electron beam with a high energy density. The electron beam is emitted from its filament, generally a tungsten filament, and irradiates on the surface of the sample. Different physical signals generated when the electron beam irradiates on the surface of the sample are detected by different types of detection devices. The detection devices include an electron detection device, a cathode fluorescence detection device, an X-ray detection device, etc. Electron signals, such as secondary electrons and backscattered electrons, are detected by the electron detection device. Most of the electron detection devices used in high-throughput electron microscopes are semiconductor detection devices, such as silicon-based PN junction detection devices.

[0004] Currently, most of the electron emission devices used in scanning electron microscopes are single-beam emission sources, that is, single-point emission, and the detection device for detecting electron signals is single-point reception, which results in low efficiency, affects the sampling throughput, and cannot achieve array acquisition of images. In addition, the existing electron emission device also has problems such as complex filament processing and easy damage. In addition, the electron emission device and the electron detection device are relatively independently arranged, and the distances between the electron emission device and the sample and between the sample and the electron detection device are relatively macroscopic. Considering the need to improve the detection efficiency of secondary electrons and backscattered electrons on the surface of the sample, the receiving area of the existing electron detection device needs to be designed relatively large, and correspondingly, a larger internal space is required for the scanning electron microscope. Summary of the Invention

[0005] To solve the above deficiencies at least to some extent, the present invention provides an electron emission device, an electron detection device, and a combination thereof.

[0006] In a first aspect, the present invention provides an electron emission device, including an insulating substrate and a metal surface. The metal surface covers one side of the insulating substrate, and a plurality of filaments are formed on one side of the metal surface. The plurality of filaments are arranged at intervals and their extending directions are parallel to each other.

[0007] Optionally, a part of the metal surface is etched to form the filaments.

[0008] Optionally, an isolation groove is provided on one side of the insulating substrate close to the filament, so that there is at least a certain interval between the emission end portion of the filament and the insulating substrate.

[0009] In a second aspect, the present invention provides an electronic detection device, including a plurality of isolation layers, a plurality of PN junctions, a plurality of electron receiving layers, a plurality of conductive posts, and a plurality of lead-out layers. The plurality of isolation layers are stacked in a stepped manner along their thickness direction to form a plurality of stepped surfaces perpendicular to the thickness direction. A plurality of the lead-out layers are respectively covered on the plurality of stepped surfaces. A plurality of the PN junctions are arranged at intervals at the bottom of the isolation layer located at the bottom layer. A plurality of the conductive posts are arranged through at least one layer of the isolation layer to electrically connect the plurality of PN junctions and the plurality of lead-out layers in a one-to-one correspondence. The lead-out layer is used to connect a lead wire. A plurality of the electron receiving layers are respectively covered on the side of the PN junction away from the isolation layer.

[0010] Optionally, the PN junction is opposite to the corresponding lead-out layer in the thickness direction, and the conductive post extends along the thickness direction.

[0011] Optionally, it further includes a cushion layer and an electron receiving expansion layer. The cushion layer is an insulating layer, and the cushion layer is provided at the bottom of the isolation layer located at the bottom layer. The electron receiving expansion layer covers the side of the cushion layer away from the isolation layer and is electrically connected to each of the plurality of electron receiving layers.

[0012] Optionally, the electron receiving expansion layer is electrically connected to the plurality of electron receiving layers through a plurality of conductive transition segments, and the width of the conductive transition segment is smaller than the width of the electron receiving layer.

[0013] Optionally, the electron receiving expansion layer, the conductive transition segment, and the electron receiving layer are an integral metal layer.

[0014] Optionally, the projected area of the lead-out layer in the thickness direction is larger than the projected area of the PN junction in the thickness direction.

[0015] In a third aspect, the present invention provides a combination of an electron emission device and an electronic detection device, including the above-mentioned electron emission device and electronic detection device. Wherein, the electronic detection device is connected to the side of the insulating substrate away from the metal surface. A plurality of the filaments and a plurality of the PN junctions are located on the same side of the combination and are in one-to-one correspondence.

[0016] The electron emission device and electron detection device provided by the present invention are in the form of multi-electron emission source emission and multi-detection point reception, which can realize the array acquisition of sample images, improve the sampling throughput and detection efficiency. The combination of the electron emission device and the electron detection device can realize emission-detection integration, and the volume of the vacuum chamber occupied by this integrated device is greatly reduced, which is conducive to promoting the miniaturization and portability of the scanning electron microscope, that is, creating conditions for the realization of a portable scanning electron microscope.

[0017] Those skilled in the art will understand the above and other objects, advantages and features of the present invention more clearly according to the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Some specific embodiments of the present invention will be described in detail hereinafter with reference to the accompanying drawings in an exemplary but non-limiting manner. The same reference numerals in the drawings denote the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0019] Figure 1 is a schematic structural diagram of the combination of the electron emission device and the electron detection device in an embodiment of the present invention Figure 1 .

[0020] Figure 2 is a schematic structural diagram of the combination of the electron emission device and the electron detection device in an embodiment of the present invention Figure 2 .

[0021] Figure 3 is Figure 1 the front view of.

[0022] Figure 4 is Figure 1 the right view of.

[0023] Figure 5 is Figure 1 the left view of.

[0024] Figure 6 is Figure 3 the B-B cross-sectional view of.

[0025] Figure 7 is a partial structural schematic diagram of the electron detection device in an embodiment of the present invention.

[0026] Figure 8 is a schematic diagram of the working principle of the combination of the electron emission device and the electron detection device in an embodiment of the present invention Figure 1 .

[0027] Figure 9 is a schematic diagram of the working principle of the combination of the electron emission device and the electron detection device in an embodiment of the present inventionFigure 2 。

[0028] Reference Signs:

[0029] Assembly 100, Insulating Substrate 1, Isolation Groove 11, Metal Surface 2, Filament 3, Isolation Layer 4, Lead-out Layer 5, PN Junction 6, Conductive Column 7, Electron Receiving Layer 8, Sample 9, Cushion Layer 101, Electron Receiving Expansion Layer 102, Conductive Transition Section 103 Detailed Embodiment

[0030] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0031] In order to improve the sampling throughput and efficiency of a scanning electron microscope and change the current situation of single-point emission and single-point reception, the present invention provides an electron emission device, an electron detection device and their combination. The electron emission device can emit multiple electron beams simultaneously, the electron detection device can receive multiple electron signal beams simultaneously, and the combination of the electron emission device and the electron detection device can realize array multi-point acquisition of electron images.

[0032] The electron emission device provided by the present invention includes an insulating substrate 1 and a metal surface 2. The metal surface 2 covers one side of the insulating substrate 1. A plurality of filaments 3 are constructed on one side of the metal surface 2, that is, a plurality of filaments 3 are located on the same side of the metal surface 2. The plurality of filaments 3 are arranged at intervals and their extending directions are parallel to each other. Filament electrodes are led out on the metal surface 2, and each filament 3 can independently emit electrons as an electron emission source. The plurality of filaments 3 arranged at intervals are combined into a plurality of electron emission sources. Therefore, the electron emission device provided by the present invention can emit multiple electron beams simultaneously.

[0033] The electron detection device provided by the present invention includes a plurality of isolation layers 4, a plurality of PN junctions 6, a plurality of electron receiving layers 8, a plurality of conductive columns 7 and a plurality of lead-out layers 5. The plurality of isolation layers 4 are stacked in a stepped manner along their thickness directions to form a plurality of stepped surfaces perpendicular to the thickness direction. It can be understood that the planes where the plurality of stepped surfaces are located are spaced and parallel to each other in the thickness direction. The plurality of lead-out layers 5 are correspondingly covered on the plurality of stepped surfaces formed by the isolation layers 4. Or rather, the open parts (stepped surfaces) on the upper surfaces of each isolation layer 4 are covered with lead-out layers 5. The lead-out layers 5 are used to connect leads. It can be understood that since the lead-out layers 5 are respectively covered on different isolation layers 4 and are isolated from each other, signal crosstalk will not occur.

[0034] A plurality of PN junctions 6 are arranged at intervals at the bottom of the isolation layer 4 located at the bottom layer. A plurality of conductive posts 7 are arranged in at least one layer of the isolation layer 4 to electrically connect the plurality of PN junctions 6 to the plurality of lead-out layers 5 in one-to-one correspondence. A plurality of electron receiving layers 8 cover one side of the PN junctions 6 away from the isolation layer 4 in one-to-one correspondence. The electron receiving layer 8 is used to receive electrons and transmit signals to the PN junction 6. The PN junction 6 generates a current that is led to the corresponding lead-out layer 5 through the corresponding conductive post 7 and led out through the corresponding lead wire. After the signal is processed, a pixel is formed at the display end. It can be understood that the plurality of PN junctions 6 receive signals independently of each other.

[0035] The combination 100 of the electron emission device and the electron detection device provided by the present invention includes the above-mentioned electron emission device and the above-mentioned electron detection device, wherein the electron detection device is connected to the side of the insulating substrate 1 away from the metal surface 2, and a plurality of filaments 3 and a plurality of PN junctions 6 are located on the same side of the combination 100, and the plurality of filaments 3 and the plurality of PN junctions 6 are in one-to-one correspondence. The electron beam emitted by the filament 3 collides with the surface of the sample 9, exciting secondary electrons and backscattered electrons. The secondary electrons and backscattered electrons are reflected onto the electron receiving layer 8 below the corresponding PN junction 6 and received by the corresponding PN junction 6. The insulating substrate 1 isolates the filament 3 from the PN junction 6 to avoid the influence of electric field interference and electron beam sputtering on the signal receiving process of the PN junction 6.

[0036] The electron emission device and the electron detection device provided by the present invention are in the form of multi-electron emission source emission and multi-detection point reception, which can realize the array acquisition of sample images and improve the sampling throughput and detection efficiency. The combination of the electron emission device and the electron detection device can realize emission-detection integration. The volume of the vacuum chamber occupied by this integrated device is greatly reduced, which is conducive to promoting the miniaturization and portability of the scanning electron microscope, creating conditions for the realization of a portable scanning electron microscope.

[0037] The following Figures 1 - 7 describes a specific embodiment of the combination 100 of the electron emission device and the electron detection device provided by the present invention.

[0038] As Figure 1 shown, the metal surface 2 covers one side of the insulating substrate 1. The insulating substrate 1 plays a supporting role for the metal surface 2 and at the same time isolates the metal surface 2 from the acquisition end of the electron detection device. In this embodiment, the metal surface 2 is a tungsten metal surface, which is deposited on one side of the insulating substrate 1 by means of evaporation through semiconductor processing technology. A plurality of filaments 3 with parallel extension directions are formed at the bottom of the metal surface 2. It can be understood that in this embodiment, the filament 3 is a tungsten filament.

[0039] The filament 3 is formed by ion etching a part of the metal surface 2, that is, after the precipitation of the metal surface 2 is completed, the metal surface 2 is ion-etched to form a plurality of filaments 3 at the bottom of the metal surface 2. The processing difficulty of the filament 3 is relatively low, and since the filament 3 is etched from the metal surface 3 and is an integral structure with the rest of the metal surface 3, the filament 3 has strong structural strength and the advantage of being not easily damaged.

[0040] Both the insulating substrate 1 and the metal surface 2 are rectangular. As Figure 1 and Figure 2 shown, a plurality of filaments 3 are arranged at intervals along the extension direction of the bottom edge of the metal surface 2, and the extension direction of the filaments 3 is perpendicular to their arrangement direction. The emission end (the free end of the filament 3) of the filament 3 emits electrons downward along the extension direction of the filament 3.

[0041] Preferably, a plurality of filaments 3 are arranged at equal intervals, so that the electron emission device can uniformly emit an electron beam to the surface of the sample 9 and uniformly collect the surface information of the sample 9.

[0042] Furthermore, a isolation groove 11 is processed on the side of the insulating substrate 1 close to the filament 3 by an etching process, so that there is at least a certain interval between at least the emission end (the free end of the filament 3) of the filament 3 and the insulating substrate 1. Specifically, the side of the filament 3 facing the insulating substrate 1 after etching is in contact with the insulating substrate 1. As Figure 2 and Figure 3 shown, the isolation groove 11 is etched at the bottom of the side of the insulating substrate 1 close to the filament 3, so that a part of the filament 3 close to its emission end protrudes relative to the insulating substrate 1, that is, it is not in contact with the insulating substrate 1, to form an electron emission source. The part of the insulating substrate 1 corresponding to the isolation groove 11 can isolate the emission end of the filament 3 from the signal acquisition end of the electron detection device, avoid the electrons generated by the lateral sputtering when the filament 3 emits electrons from interfering with the detector signal, and also play a role in protecting the emission end of the filament 3.

[0043] In this embodiment, the bottom of the insulating substrate 1 is located below the bottom of the filament 3 to better isolate the filament 3 from the signal acquisition end and avoid interfering with the signal acquisition process.

[0044] Optionally, the electron detection device is connected to the insulating substrate 1 by an adhesion process.

[0045] As Figure 1 and Figure 5As shown, a plurality of isolation layers 4 of the electronic detection device are stacked in sequence along its thickness direction to form a stepped structure. In this embodiment, the thickness direction of the isolation layer 4 is parallel to the extending direction of the filament 3, and the number of the isolation layers 4 is equal to the number of the filaments 3. The upper surface areas of the plurality of isolation layers 4 decrease successively from bottom to top. The isolation layers 4 are stacked to form a plurality of upward stepped surfaces, and the arrangement direction of the plurality of stepped surfaces is the same as the arrangement direction of the filaments 3. Each stepped surface is covered with a corresponding lead-out layer 5. The lead-out layers 5 are isolated from each other and do not contact each other. The lead-out layer 5 is welded to the lead wire. Optionally, the lead-out layer 5 is formed by metal evaporation.

[0046] A plurality of PN junctions 6 are arranged on the lower surface of the lowermost isolation layer 4 and are electrically connected to the plurality of lead-out layers 5 one by one through a plurality of conductive posts 7.

[0047] Optionally, the PN junction 6 is manufactured by a semiconductor doping process and is constructed by different doped layers.

[0048] Optionally, the conductive post 7 is formed in the isolation layer 4 by means of metal implantation and is used to lead out the signal of the corresponding PN junction 6 to the lead-out layer 5. The contact between the conductive post 7 and the lead-out layer 5 extends the signal lead-out end to a surface, facilitating the welding between the lead wire and the lead-out layer 5.

[0049] In this embodiment, as Figure 6 shown, the PN junction 6 is opposite to the corresponding lead-out layer 5 in the thickness direction of the isolation layer 4. The conductive post 7 extends along the thickness direction of the isolation layer 4 and penetrates at least one isolation layer 4. Moreover, the projected area of the lead-out layer 5 in the thickness direction of the isolation layer 4 is larger than the projected area of the corresponding PN junction 6 in the thickness direction of the isolation layer 4, which is more convenient for the welding process of the lead wire.

[0050] The signal acquisition end of the electronic detection device is composed of the PN junction 6 and the electron receiving layer 8 covering the bottom surface of the PN junction 6. The electron receiving layer 8 is used to receive electrons and transmit the signal to the PN junction 6. The PN junction 6 generates current, which is led to the corresponding lead-out layer 5 through the corresponding conductive post 7. The stepped hierarchical design between the isolation layers 4 enables the lead-out layers 5 to be isolated from each other and not to contact each other, realizing the separate lead-out of the signal acquisition end, that is, realizing the isolation of the signal, and converting the small-area PN junction 6 into a large-area lead-out layer 5, which is convenient for the welding process of the lead wire.

[0051] It can be understood that in this embodiment, the numbers of the filament 3, the isolation layer 4, the lead-out layer 5, the PN junction 6, the conductive post 7, and the electron receiving layer 8 are all equal.

[0052] Furthermore, as Figure 2 and Figure 7As shown in the figure, the electronic detection device provided in this embodiment further includes a cushion layer 101 and an electronic reception amplification layer 102. The cushion layer 101 is an insulating layer, that is, the cushion layer 101 is non-conductive. The cushion layer 101 is provided at the bottom of the lowermost isolation layer 4 and can be formed by precipitation at the bottom of the lowermost isolation layer 4. The electronic reception amplification layer 102 is supported by the cushion layer 101, covers the side of the cushion layer 101 away from the isolation layer 4, and is electrically connected to each of a plurality of electronic reception layers 8. The arrangement of the electronic reception amplification layer 102 and the cushion layer 101 greatly increases the electronic reception area of the electronic detection device and improves the electronic detection efficiency.

[0053] In some embodiments, the electronic reception amplification layer 102 can be welded with a lead wire to serve as another lead-out end of the signal.

[0054] Specifically, as Figure 2 shown, the electronic reception amplification layer 102 is electrically connected to a plurality of electronic reception layers 8 through a plurality of conductive transition segments 103, and the width of the conductive transition segments 103 is smaller than the width of the electronic reception layers 8. And the conductive transition segments 103 also contact the cushion layer 101 and are supported by the cushion layer 101.

[0055] In this embodiment, as Figure 2 shown, the electronic reception amplification layer 102, the conductive transition segments 103 and the electronic reception layers 8 are an integral metal layer.

[0056] When processing the assembly 100 in this embodiment, a substrate is first deposited at the bottom of the lowermost isolation layer 4. Through the semiconductor doping process, a plurality of PN junctions 6 are directly formed on the substrate. The non-doped part of the substrate becomes the cushion layer 101, and the cushion layer 101 provides support for the subsequent deposition of the metal layer.

[0057] Next, according to Figure 8 and Figure 9 describe the working process and working principle of the assembly 100 of the electron emission device and the electron detection device provided in the embodiment of the present invention.

[0058] As Figure 8 shown, the filament 3 emits an electron beam as an electron source. The electron beam reacts with the sample 10 to excite secondary electrons and backscattered electrons. The secondary electrons and backscattered electrons are received by the corresponding PN junctions 6 through the electronic reception layers 8, and the scattered electrons are blocked by the insulating substrate 1 to avoid interfering with the signal.

[0059] As Figure 9 shown, the filaments 3 are numbered a - e. Taking the filament a as an example, the electrons emitted by the filament a are received through the signal acquisition terminal A, led out to the lead-out layer A' through the corresponding conductive column 7, and led out by the lead wire electrically connected to the lead-out layer A'. The signal is processed to form a pixel A" at the display terminal. Through the array arrangement of the filaments a - e, synchronous multi-point scanning imaging is realized.

[0060] As described above, it is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A combination of an electron emission device and an electron detection device, characterized in that, Comprising: An electron emission device, including an insulating substrate and a metal surface, the metal surface covering one side of the insulating substrate, and a plurality of filaments being constructed on one side of the metal surface, the plurality of filaments being arranged at intervals and having parallel extending directions; An electron detection device, including a plurality of isolation layers, a plurality of PN junctions, a plurality of electron receiving layers, a plurality of conductive posts, and a plurality of lead-out layers; The plurality of isolation layers are stacked in a stepped manner along their thickness direction to form a plurality of stepped surfaces perpendicular to the thickness direction, the plurality of lead-out layers respectively covering the plurality of stepped surfaces, the plurality of PN junctions being arranged at intervals at the bottom of the isolation layer at the lowermost layer, the plurality of conductive posts being inserted through at least one of the isolation layers so as to electrically connect the plurality of PN junctions and the plurality of lead-out layers in one-to-one correspondence, the lead-out layers being used for connecting leads, and the plurality of electron receiving layers respectively covering the sides of the PN junctions away from the isolation layers; Wherein, the electron detection device is connected to the side of the insulating substrate away from the metal surface, and the plurality of filaments and the plurality of PN junctions are located on the same side of the combination and are in one-to-one correspondence.

2. The combination of an electron emission device and an electron detection device according to claim 1, characterized in that, A part of the metal surface of the electron emission device is etched to form the filaments.

3. The combination of an electron emission device and an electron detection device according to claim 1, characterized in that, An isolation groove is provided on the side of the insulating substrate of the electron emission device close to the filaments, so that there is at least a certain interval between the emission end portions of the filaments and the insulating substrate.

4. The combination of an electron emission device and an electron detection device according to claim 1, characterized in that, The PN junctions of the electron detection device are opposite to the corresponding lead-out layers in the thickness direction, and the conductive posts extend along the thickness direction.

5. The combination of an electron emission device and an electron detection device according to claim 1, characterized in that, The electron detection device further includes a cushion layer and an electron receiving expansion layer, the cushion layer being an insulating layer, the cushion layer being provided at the bottom of the isolation layer at the lowermost layer, and the electron receiving expansion layer covering the side of the cushion layer away from the isolation layer and being electrically connected to each of the plurality of electron receiving layers.

6. The combination of an electron emission device and an electron detection device according to claim 5, characterized in that, The electron receiving expansion layer is electrically connected to the plurality of electron receiving layers through a plurality of conductive transition segments, and the width of the conductive transition segments is smaller than the width of the electron receiving layers.

7. The combination of an electron emission device and an electron detection device according to claim 6, characterized in that, The electron receiving expansion layer, the conductive transition segments, and the electron receiving layers are an integral metal layer.

8. The combination of an electron emission device and an electron detection device according to claim 1, characterized in that, The projected area of the lead-out layer of the electron detection device in the thickness direction is larger than the projected area of the PN junction in the thickness direction.

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