Semiconductor electron detection device and scanning electron microscope

Abstract

The application discloses a semiconductor electron detection device and a scanning electron microscope, which comprises two or more than two semiconductor detection units which are independent of each other, the two or more than two semiconductor detection units have the same detection area, and the detection surfaces of the semiconductor detection units are alternately and uniformly distributed in the same circumference. The technical scheme provided by the application can collect the electronic signals received by different semiconductor detection units through time sharing, reduce the restriction of signal residence time on sampling frequency, improve the limit sampling flux of the scanning electron microscope, and realize the multiplication of sampling efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electron microscopes, in particular to a semiconductor electron detection device and a scanning electron microscope with the same. BACKGROUND

[0002] Scanning Electron Microscope (SEM) is a commonly used microscopic analysis instrument that uses various physical signals excited by a focused electron beam when scanning the sample surface to modulate imaging. Different physical signals require different types of detection systems, which can be roughly divided into three categories, namely electron detector, cathodoluminescence detector and X-ray detector. Electron signals are detected by electron detectors, and the commonly used electron detectors include coaxial electron detectors and lateral electron detectors. The coaxial electron detector is installed above the sample stage and is used to detect secondary electrons and / or backscattered electrons. The electron detector currently used in high-throughput electron microscopes is mainly a semiconductor detector, such as a silicon-based PN junction type detector, but this type of detector is limited by its own electron-hole pair generation process, and the signal residence time of the detector is not more than 10 ns, which limits the acquisition frequency and becomes an important factor restricting the improvement of signal acquisition throughput. SUMMARY

[0003] In order to overcome the above shortcomings of the prior art, the present application provides a semiconductor electron detection device and a scanning electron microscope with the same.

[0004] According to a first aspect of the present application, a semiconductor electron detection device is provided, comprising two or more semiconductor detection units independent of each other, the two or more semiconductor detection units having the same detection area, and the detection surfaces of each semiconductor detection unit being uniformly distributed in sequence in the same circumference.

[0005] Optionally, the semiconductor electron detection device comprises a final-stage semiconductor detection unit and a front-stage semiconductor detection unit, the back surface of the front-stage semiconductor detection unit is attached to the front surface of the final-stage semiconductor detection unit, and a plurality of hollow parts are uniformly distributed on the front-stage semiconductor detection unit.

[0006] Optionally, the hollow part is a circular hole.

[0007] Optionally, the hollow part is a square hole.

[0008] Optionally, the hollow part is a fan-shaped hollow part.

[0009] Optionally, in the same radial direction, the fan-shaped hollow part is a continuous single fan-shaped hollow part or a plurality of fan-shaped hollow parts arranged at intervals.

[0010] Optionally, the front-stage semiconductor detection unit comprises two or more than two front-stage semiconductor detection units stacked in sequence, and the hollow part on the front-stage semiconductor detection unit with a relatively front position is larger than the hollow part on the front-stage semiconductor detection unit with a relatively rear position and is in communication with each other.

[0011] Optionally, the semiconductor detection device comprises an even number of sector-shaped semiconductor detectors with the same size, and the number is greater than or equal to 4, and the semiconductor detection device comprises two semiconductor detection units, and each semiconductor detection unit comprises two sector-shaped semiconductor detectors with opposite positions.

[0012] Optionally, the semiconductor electron detection device is provided with a center through hole.

[0013] According to the second aspect of the present application, a scanning electron microscope is provided, which comprises an electron gun and a sample stage, and further comprises the semiconductor electron detection device with a center through hole, and the semiconductor electron detection device is located between the electron gun and the sample stage.

[0014] The above technical solution provided by the present application can collect the electronic signals received by different semiconductor detection units by time sharing, reduce the restriction of signal residence time on sampling frequency, improve the limit sampling flux of the scanning electron microscope, and realize the multiplication of sampling efficiency.

[0015] The above and other objects, advantages and features of the present application will become more apparent from the following detailed description of some embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0016] Some specific embodiments of the present application will be described in detail hereinafter with reference to the accompanying drawings, which are presented by way of illustration and not by way of limitation. The same reference numbers in the drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that the drawings are not necessarily drawn to scale. In the drawings:

[0017] Figure 1 is an exploded structural schematic diagram of the semiconductor electron detection device in one embodiment of the present application.

[0018] Figure 2 is Figure 1 is a sectional structural schematic diagram of the semiconductor electron detection device.

[0019] Figure 3 is a schematic diagram of the time-sharing signal collection principle in one embodiment of the present application.

[0020] Figure 4 is a structural schematic diagram of the semiconductor electron detection device in another embodiment of the present application.

[0021] Reference signs:

[0022] 1. A front-stage semiconductor detection unit, 11. A hollowed part, 2. A final-stage semiconductor detection unit, 3. A central through hole, 4. A lead wire, 5. A fan-shaped semiconductor detector. DETAILED DESCRIPTION

[0023] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0024] First, the prior art related to the technical solutions provided by the embodiments of the present application will be briefly introduced as follows:

[0025] The so-called time division multiplexing refers to taking time as the parameter for signal segmentation transmission, so that the signals of different channels do not overlap on the time axis, so that different signals are transmitted in different time. The entire transmission time is divided into time intervals that do not overlap, also known as time slots. The time division multiplexing technology allocates these time slots to each signal source, and each time slot can only be occupied by one signal. By transmitting a part of each signal in time, a circuit transmits multiple signals, and each short moment on the circuit only has one signal.

[0026] The scanning electron microscope mainly includes the following components:

[0027] Electron optical system, which includes an electron gun and a lens system. The function of the electron gun is to generate an electron illumination source. The function of the lens system is (1) to reduce the size of the virtual light source from tens of microns to 5 nm (or smaller), and continuously variable from tens of microns to several nanometers, (2) to control the opening angle of the electron beam, which can be variable in the range of 10-2~10-3 rad, (3) the formed focused electron beam can be raster scanned on the surface of the sample, and the scanning angle range is variable. In order to obtain the above scanning 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 function of the scanning coil is to deflect the electron beam and make it regularly swing on the sample surface. The function of the diaphragm includes filtering the off-axis electrons in the electron beam and adjusting the image depth of field.

[0028] Mechanical system, which includes a support part and a sample chamber. The sample chamber has a sample stage, and the four walls are generally provided with several windows. In addition to installing an electron detector, other detectors and spectrometers can also be installed.

[0029] Vacuum system, the vacuum system is very important in the electron optical instrument, because the electron beam can only be generated and manipulated in vacuum. The commonly used high vacuum system includes dry pump system, turbo molecular pump system and ion pump system.

[0030] The signal collecting, processing and displaying system, the electron beam emitted by the electron gun of the scanning electron microscope is converged into a point light source after being focused, the point light source forms a high-energy electron beam under the acceleration voltage, the high-energy electron beam is focused into a light spot with a tiny diameter via an electromagnetic lens, after passing through the last stage electromagnetic lens with a scanning coil, the electron beam scans the sample surface point by point in a grating manner, and different depth physical signals are excited at the same time. The physical signals are received by different signal detectors and transmitted to the computer display screen through an amplifier in a synchronous manner to form a real-time imaging record. The sample will produce various physical signals under the action of the incident electron beam, such as Auger electrons (Au E), secondary electrons (SE), backscattered electrons (BSE), X-rays (characteristic X-rays, continuous X-rays), cathodoluminescence (CL), absorbed electrons (AE) and transmitted electrons. Different physical signals require different types of detection systems. Generally, they can be divided into three categories, namely, electron detectors, cathodoluminescence detectors and X-ray detectors.

[0031] The electron optical system is generally located in the lens barrel above the sample chamber, the signal detector is usually located in the sample chamber or the lens barrel, the electron gun, the lens system and the signal detector are connected with the external power supply, and the vacuum system provides a vacuum environment for the lens barrel and the sample chamber.

[0032] In order to improve the collection flux of the electron signal, the application provides a semiconductor electron detection device with time-sharing multiplexing characteristics and a scanning electron microscope with the semiconductor electron detection device. Through the combination application of multiple detection units, the collection flux can be doubled. The semiconductor electron detection device includes two or more semiconductor detection units which are independent of each other and have the same detection area. The detection surfaces of the semiconductor detection units are alternately and uniformly distributed in the same circumference. The semiconductor electron detection device can also have a central through hole as an incident electron beam channel. The uniform distribution includes radial uniform distribution and circumferential uniform distribution.

[0033] The above technical solution provided by the application can collect the electron signals received by different semiconductor detection units in a time-sharing manner, reduce the restriction of signal residence time on sampling frequency, improve the limit sampling flux of the scanning electron microscope, and double the sampling efficiency. The following will be described in detail through several specific embodiments.

[0034] Embodiment 1

[0035] As Figure 1 and Figure 2As shown, in the embodiment, the semiconductor electron detection device includes a front-stage semiconductor detection unit 1 and a final-stage semiconductor detection unit 2, both of which are independent semiconductor detectors and are connected to a signal acquisition circuit through respective lead wires 4. The back surface of the front-stage semiconductor detection unit 1 is attached to the front surface (i.e., the electron signal receiving surface) of the final-stage semiconductor detection unit 2, both of which are provided with a central through hole 3, and the two central through holes 3 are mutually penetrable. The front-stage semiconductor detection unit 1 is uniformly provided with a plurality of hollow parts 11, which are circular holes in the embodiment. The detection area of the front-stage semiconductor detection unit 1 is the same as that of the final-stage semiconductor detection unit 2, that is, the area of the front-stage semiconductor detection unit 1 available for detection after removing the hollow parts 11 is equal to the sum of the cross-sectional areas of the hollow parts 11. The sum of the cross-sectional areas of the hollow parts 11 is the area of the final-stage semiconductor detection unit 2 capable of receiving electron signals through the hollow parts 11.

[0036] When it is used in a scanning electron microscope, the semiconductor electron detection device is located between an electron gun and a sample stage, the front surface (i.e., the electron signal receiving surface) of the front-stage semiconductor detection unit 1 faces the sample stage, and an electron beam emitted by the electron gun passes through the central through hole 3 and hits an observed sample carried by the sample stage, and the generated secondary electrons and backscattered electrons are reflected from the sample to the semiconductor electron detection device, part of the electrons hit the electron signal receiving surface of the front-stage semiconductor detection unit 1 and are detected by the front-stage semiconductor detection unit 1, and part of the electron signals pass through the front-stage semiconductor detection unit 1 through the hollow parts 11 and hit the electron signal receiving surface of the final-stage semiconductor detection unit 2 and are detected by the final-stage semiconductor detection unit 2. The electron signals on the front-stage semiconductor detection unit 1 and the final-stage semiconductor detection unit 2 are respectively led out to the signal acquisition circuit through the respective lead wires 4. The signal acquisition circuit uses time-division multiplexing technology to collect the electron signals on the front-stage semiconductor detection unit 1 and the final-stage semiconductor detection unit 2 in time division, and the technology and the corresponding circuit structure are mature existing technologies, which will not be described here. As shown in the figure, Figure 3 As shown, assuming that the signal residence time of the front-stage semiconductor detection unit 1 and the final-stage semiconductor detection unit 2 is 10 ns, the highest limit sampling frequency in the traditional way is 100M, and by using the semiconductor electron detection device provided in the embodiment, the two semiconductor detection units can be periodically collected in time division within a time interval of 10 ns by using time-division multiplexing, so as to increase the limit sampling frequency to 200M.

[0037] Embodiment 2

[0038] The difference between this embodiment and Embodiment 1 is that, in this embodiment, the hollow parts 11 are square.

[0039] Embodiment 3

[0040] The difference between this embodiment and Embodiment 1 is that, in this embodiment, the hollow part 11 is a fan shape, and in the same radial direction, it can be a continuous single fan-shaped hollow part, or it can be a plurality of fan-shaped hollow parts arranged at intervals.

[0041] Embodiment 4

[0042] As shown in the figure, in this embodiment, the semiconductor electron detection device includes a center through hole 3 and four fan-shaped semiconductor detectors 5 of the same size arranged in a circle around the center through hole 3, and the two opposite fan-shaped semiconductor detectors 5 constitute a semiconductor detection unit. Figure 4

[0043] In addition, compared with Embodiment 1, in some embodiments, the hollow part 11 can also be of any other shape, and in some embodiments, the front-stage semiconductor detection unit 1 can include a plurality of layers, and the hollow part 11 on the front-stage semiconductor detection unit 1 in the front relative position is larger than the hollow part 11 on the front-stage semiconductor detection unit 1 in the rear relative position and is in communication with each other. Compared with Embodiment 2, in some embodiments, an even number of fan-shaped semiconductor detectors 5 greater than 4 can be included. When used for other purposes and without the need to reserve an electron beam channel, the center through hole on the semiconductor electron detection device can also be removed.

[0044] The signal acquisition principles of the semiconductor electron detection devices in the above embodiments are the same as those in Embodiment 1, and will not be repeated here.

[0045] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.​

Claims

1. A semiconductor electron detecting device, characterized by comprising: The semiconductor detecting device comprises two or more semiconductor detecting units which are independent of each other and have the same detecting area, and the detecting surfaces of the semiconductor detecting units are alternately and uniformly distributed in the same circumference. The two or more semiconductor detecting units comprise a final-stage semiconductor detecting unit and a front-stage semiconductor detecting unit, the back surface of the front-stage semiconductor detecting unit is attached to the front surface of the final-stage semiconductor detecting unit, and a plurality of hollow parts are uniformly distributed on the front-stage semiconductor detecting unit. The detecting area of the front-stage semiconductor detecting unit is the same as that of the final-stage semiconductor detecting unit, and the area available for detection of the front-stage semiconductor detecting unit after removing the hollow parts is equal to the sum of the cross-sectional areas of the hollow parts.

2. The semiconductor electron detection device according to claim 1, characterized in that, The hollow parts are circular holes.

3. The semiconductor electron detection device according to claim 1, wherein The hollow parts are square holes.

4. The semiconductor electron detection device according to claim 1, characterized by The hollow parts are fan-shaped hollow parts.

5. The semiconductor electron detection device according to claim 4, wherein In the same radial direction, the fan-shaped hollow parts are continuous single fan-shaped hollow parts or a plurality of fan-shaped hollow parts arranged at intervals.

6. The semiconductor electron detection device according to claim 1, wherein The front-stage semiconductor detecting unit comprises two or more front-stage semiconductor detecting units which are stacked in sequence, the hollow parts on the front-stage semiconductor detecting units in the front relative position are larger than the hollow parts on the front-stage semiconductor detecting units in the rear relative position, and the hollow parts on the front-stage semiconductor detecting units in the front relative position and the hollow parts on the front-stage semiconductor detecting units in the rear relative position are in communication with each other.

7. The semiconductor electron detection device according to claim 1, wherein The semiconductor electronic detecting device comprises an even number of fan-shaped semiconductor detectors which are the same in size and are arranged in a circle, and the semiconductor detecting device comprises four or more semiconductor detecting units.

8. The semiconductor electron detection device according to any one of claims 1 to 7, characterized by The semiconductor electronic detecting device is provided with a center through hole.

9. A scanning electron microscope comprising an electron gun and a sample stage, characterized in that, The semiconductor electronic detecting device according to claim 8 is further arranged between the electron gun and the sample table.

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