Scanning electron microscope apparatus

Abstract

This application discloses a scanning electron microscope device, comprising: an electron gun, the cavity of which is electrically connected to a first reference voltage terminal; a detector disposed inside the cavity of the electron gun and electrically connected to the first reference voltage terminal; an amplifier, the input terminal of which is electrically connected to the output terminal of the detector and electrically connected to the first reference voltage terminal; and an analog-to-digital converter (ADC), the input terminal of which is electrically connected to the output terminal of the amplifier, a first terminal of the ADC's power supply being electrically connected to the ADC, and a second terminal of the ADC's power supply being electrically connected to a second reference voltage terminal. The aforementioned scanning electron microscope device can improve the quality of semiconductor images generated by the scanning electron microscope.

Description

Technical Field

[0001] This application belongs to the field of semiconductor testing equipment, and in particular relates to a scanning electron microscope device. Background Technology

[0002] In the semiconductor inspection process, scanning electron microscopes (SEM) are often used to collect the signal of charged particle beams reflected by the semiconductor for imaging in order to detect semiconductor defects.

[0003] However, the aforementioned charged particle beam signals are often interfered with by various noises in the environment or signal circuits during signal transmission, which can cause the final generated image to be misaligned or blurred, affecting the detection of semiconductor defects. Utility Model Content

[0004] This application provides a data processing method, apparatus, device, medium, and product that can improve the quality of semiconductor images generated by a scanning electron microscope.

[0005] In a first aspect, embodiments of this application provide a scanning electron microscope apparatus, comprising:

[0006] The electron gun has its cavity electrically connected to the first reference voltage terminal.

[0007] The detector is located inside the cavity of the electron gun and is electrically connected to the first reference voltage terminal.

[0008] The amplifier has its input terminal electrically connected to the detector's output terminal and is also electrically connected to the first reference voltage terminal.

[0009] An analog-to-digital converter (ADC) is provided, with its input terminal electrically connected to the output terminal of an amplifier. A first terminal of the ADC's power supply is also electrically connected to the ADC, and a second terminal of the ADC's power supply is electrically connected to a second reference voltage terminal.

[0010] The scanning electron microscope device provided in this application eliminates the potential difference between the electron gun cavity, detector, and amplifier by electrically connecting them to a first reference voltage terminal in the electron beam detection module. This ensures that the potentials of the electron gun cavity, detector, and amplifier are the same, preventing interference to the charged particle beam signal caused by potential differences and improving the transmission accuracy of the charged particle beam signal. Simultaneously, the first terminal of the analog-to-digital converter's power supply is electrically connected to the converter, and its second terminal is electrically connected to a second reference voltage terminal. This allows for the extraction of noise generated by the converter. Consequently, the image generated after the charged particle beam signal detected by the detector is amplified by the amplifier and the analog signal is converted to a digital signal by the analog-to-digital converter exhibits high resolution, high contrast, and low distortion, facilitating the observation of semiconductor defects. Attached Figure Description

[0011] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of a scanning electron microscope apparatus provided for some embodiments of this application.

[0013] Figure 2 This is a schematic diagram of another scanning electron microscope device provided for some embodiments of this application.

[0014] Figure 3 This is a schematic diagram of another scanning electron microscope device provided for some embodiments of this application.

[0015] Figure 4 This is a partial schematic diagram of a noise shielding component provided for some embodiments of this application.

[0016] Figure 5 This is a schematic diagram showing the connection of the output terminal of an amplifier provided in some embodiments of this application. Detailed Implementation

[0017] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0018] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0019] Before describing the technical solutions provided in the embodiments of this application, in order to facilitate understanding of the embodiments of this application, this application first specifically explains the problems existing in the related technologies:

[0020] In the semiconductor inspection process, a charged particle beam is often emitted from the electron gun of a scanning electron microscope (SEM) and the signal of the charged particle beam reflected by the semiconductor is collected by a detector to form an image in order to detect semiconductor defects.

[0021] However, in the process of imaging charged particle beam signals based on semiconductor reflection, it is necessary to first amplify the acquired charged particle beam signals using an amplification circuit to obtain the amplified charged particle beam signals. Then, the amplified charged particle beam signals are converted from analog to digital by an analog-to-digital converter to generate an image.

[0022] The charged particle beam signal is often interfered with by various noises in the environment or signal circuit during the transmission process of the amplification circuit, which causes the final generated image to be misaligned or blurred, thus adversely affecting the defect detection of semiconductors.

[0023] Therefore, this application provides a scanning electron microscope device that can solve the above-mentioned problems. The following is a detailed description of the scanning electron microscope device provided in this application.

[0024] In some embodiments, such as Figure 1 As shown, this application provides a scanning electron microscope device, which may include:

[0025] An electron gun 101 is provided, with its cavity electrically connected to a first reference voltage terminal 10; a detector 102 is disposed inside the cavity of the electron gun 101 and is electrically connected to the first reference voltage terminal 10; an amplifier 103 is provided, with its input terminal electrically connected to the output terminal of the detector 102 and the amplifier electrically connected to the first reference voltage terminal; an analog-to-digital converter 104 is provided, with its input terminal electrically connected to the output terminal of the amplifier; a first terminal of a power supply 105 for the analog-to-digital converter is electrically connected to the analog-to-digital converter; and a second terminal of the power supply for the analog-to-digital converter is electrically connected to a second reference voltage terminal 20.

[0026] like Figure 1 As shown, the electron gun 101 is a device for emitting a beam of charged particles into a semiconductor. The cavity of the electron gun 101 can be electrically connected to the first reference voltage terminal 10, so that the voltage of the cavity of the electron gun 101 is consistent with that of the first reference voltage terminal.

[0027] like Figure 1 The detector 102 is disposed inside the cavity of the electron gun. The detector can receive the charged particle beam reflected by the semiconductor, such as secondary electrons or backscattered electrons reflected by the semiconductor. The detector 102 can be electrically connected to the first reference voltage terminal 10, so that the reference potential of the charged particle beam signal collected by the detector 102 is kept consistent with the first reference voltage terminal, which can reduce the interference of noise on the charged particle beam signal.

[0028] Please refer to Figure 1 The input terminal of amplifier 103 is electrically connected to the output terminal of detector 102. Amplifier 103 amplifies the charged particle beam signal acquired by detector 102 to obtain an amplified charged particle beam signal. At the same time, amplifier 103 can be electrically connected to the first reference voltage terminal 10, so that the potentials of amplifier 103, detector 102 and the cavity of electron gun 101 are kept consistent, avoiding common-mode noise and ensuring the stability of charged particle beam signal during transmission.

[0029] Please continue to refer to this. Figure 1 The input terminal of the analog-to-digital converter 104 can be electrically connected to the output terminal of the amplifier 103. The analog-to-digital converter 104 can convert the amplified charged particle beam signal from an analog signal to a digital signal to generate a semiconductor image. The first terminal of the power supply 105 of the analog-to-digital converter 104 is electrically connected to the analog-to-digital converter, and the second terminal of the power supply can be electrically connected to the second reference voltage terminal 20. This allows noise generated by the power supply 105 of the analog-to-digital converter 104 to be discharged through the second reference voltage terminal, avoiding its influence on the charged particle beam signal.

[0030] This embodiment of the application eliminates the potential difference between the electron gun cavity, detector, and amplifier in the electron beam detection module by electrically connecting them to the first reference voltage terminal. This ensures that the potentials of the electron gun cavity, detector, and amplifier are the same, avoiding common-mode noise and improving the transmission accuracy of the charged particle beam signal. Simultaneously, by electrically connecting the first terminal of the analog-to-digital converter's power supply to the converter and the second terminal to the second reference voltage terminal, noise generated by the converter can be extracted. This results in a clearer image generated after the charged particle beam signal detected by the detector is amplified by the amplifier and after the analog-to-digital converter converts the analog signal into a digital signal, facilitating the user's observation of semiconductor defects.

[0031] In some embodiments, such as Figure 2 As shown, amplifier 103 includes adder amplifier 202 and multiple differential amplifiers 201; the multiple differential amplifiers 201 are connected in parallel between the output terminal of detector 102 and the input terminal of adder amplifier 202; the output terminal of adder amplifier 202 is electrically connected to the input terminal of analog-to-digital converter 104, wherein the first terminal of the power supply 203 of adder amplifier 202 is electrically connected to adder amplifier 202, and the second terminal of the power supply 203 of adder amplifier 202 is electrically connected to the second reference voltage terminal 20.

[0032] Here, the aforementioned differential amplifiers 201 can amplify multiple sub-charged particle beams to obtain multiple amplified sub-charged particle beams, and the adder amplifier 202 can sum and superimpose the multiple amplified sub-charged particle beams to obtain an amplified charged particle beam.

[0033] For example, such as Figure 2 As shown, the first differential amplifier 2011 and the second differential amplifier 2012 are connected in parallel between the output of the detector 102 and the input of the adder amplifier 202. The two differential amplifiers can have the same gain. The two differential amplifiers can amplify the first charged particle beam signal and the second charged particle beam signal respectively, to obtain the first amplified charged particle beam signal and the second amplified charged particle beam signal. By setting the differential amplifier, common-mode noise can be suppressed to avoid affecting the charged particle beam signal.

[0034] like Figure 2The aforementioned adder amplifier 202 can sum and superimpose the first amplified charged particle beam signal and the second amplified charged particle beam signal to obtain the amplified charged particle beam signal. Furthermore, the first terminal of the power supply 203 of the adder amplifier 202 is electrically connected to the adder amplifier 202, and the second terminal of the power supply 203 is electrically connected to the second reference voltage terminal 20. This allows noise generated by the power supply 203 of the adder amplifier 202 to be discharged through the second reference voltage terminal, avoiding its influence on the charged particle beam signal.

[0035] In some examples, the power supply 203 of the adder amplifier 101 described above can be connected to the second reference voltage terminal 20 in a star topology isolated from the power supply 105 of the analog-to-digital converter 104.

[0036] This embodiment of the application uses an amplifier comprising multiple differential amplifiers and an adder amplifier. Multiple sub-charged particle beams are amplified using the differential amplifiers to obtain amplified sub-charged particle beams, which suppresses common-mode noise. Then, the multiple amplified sub-charged particle beams are summed and superimposed using the adder amplifier to obtain amplified charged particle beam. This achieves high-precision amplification of the charged particle beam signal, facilitating image generation. Simultaneously, the first terminal of the adder amplifier's power supply is electrically connected to the adder amplifier, and its second terminal is electrically connected to a second reference voltage terminal. This avoids the adder amplifier's power supply affecting the charged particle beam signal, improving image display quality.

[0037] In some embodiments, such as Figure 2 As shown, the scanning electron microscope apparatus may also include:

[0038] The variable gain amplifier 204 has its input terminal electrically connected to the output terminal of the adder amplifier 202, its output terminal electrically connected to the input terminal of the analog-to-digital converter 104, its power supply 2041 first terminal electrically connected to the analog-to-digital converter 302, and its power supply 2041 second terminal electrically connected to the second reference voltage terminal.

[0039] This embodiment of the application sets the input terminal of the variable gain amplifier to be electrically connected to the output terminal of the adder amplifier. Through the gain adjustment function of the variable gain amplifier, it can adapt to input signals of different amplitudes, avoid signal overload or signal-to-noise ratio degradation, improve the quantization accuracy of the analog-to-digital converter, and improve the quality of the generated image. Furthermore, the first terminal of the power supply of the variable gain amplifier is electrically connected to the variable gain amplifier, and the second terminal is electrically connected to the second reference voltage terminal, which can exhaust the noise generated by the power supply of the variable gain amplifier, thus improving the display effect of the image.

[0040] In some embodiments, such as Figure 2 As shown, the scanning electron microscope described above may further include:

[0041] The first filter 205 has its first end electrically connected to the first end of the power supply 105 of the analog-to-digital converter 104, and its second end electrically connected to the analog-to-digital converter 104.

[0042] In some examples, the first filter mentioned above can be a π-type LC filter. By setting the first filter, the noise of the power supply of the analog-to-digital converter can be effectively filtered out, the interference of the power supply of the analog-to-digital converter on the signal transmitted in the circuit can be reduced, and the conversion accuracy of the analog-to-digital converter can be improved when performing analog-to-digital conversion.

[0043] In some embodiments, such as Figure 2 As shown, the scanning electron microscope described above may further include:

[0044] The second filter 206 has its first terminal electrically connected to the first terminal of the power supply of the amplifier 103, and its second terminal electrically connected to the amplifier 103.

[0045] Here, the second filter mentioned above can be a π-type LC filter.

[0046] In some embodiments, such as Figure 2 As shown, the second filter 206 may include a first sub-filter 2061 and a second sub-filter 2062. The first terminal of the first sub-filter 2061 is electrically connected to the first terminal of the power supply 203 of the adder amplifier 202, and the second terminal of the first sub-filter 2061 is electrically connected to the adder amplifier 202. The first terminal of the second sub-filter 2062 is electrically connected to the first terminal of the power supply 2041 of the variable gain amplifier 204, and the second terminal of the second sub-filter 2062 is electrically connected to the variable gain amplifier 204.

[0047] In this embodiment of the application, by placing a second filter between the first terminal of the amplifier's power supply and the amplifier, noise from the amplifier's power supply can be filtered out, ensuring that the amplified charged particle beam signal obtained by the amplifier when amplifying the charged particle beam signal is undistorted.

[0048] In some embodiments, such as Figure 3 As shown, the scanning electron microscope also includes:

[0049] Noise shielding assembly 301, wherein the amplifier is disposed inside the noise shielding assembly.

[0050] In some examples, the aforementioned differential amplifiers 201, adder amplifiers 202, and variable gain amplifiers 204 can all be housed within the aforementioned noise shielding assembly.

[0051] like Figure 3 As shown, a noise shielding component 301 can be provided, and the amplifier 103 can be disposed inside the noise shielding component.

[0052] The embodiments of this application can shield external noise from interfering with the amplifier by setting a noise shielding component, so that the amplified charged particle beam signal obtained when the charged particle beam signal is amplified by the above amplifier is distortion-free.

[0053] In some embodiments, such as Figure 4 As shown, Figure 4 This is a partial schematic diagram of an exemplary noise shielding component, which includes a housing 302 and an electromagnetic shielding layer 303 disposed inside the housing.

[0054] In some examples, such as Figure 4 As shown, the housing 302 and the electromagnetic shielding layer 303 are electrically connected to the third reference voltage terminal 30.

[0055] Here, the aforementioned housing can be a metal housing. By setting an electromagnetic shielding layer inside the housing and connecting the housing and the metal shielding layer to the third reference voltage terminal 30, external noise can be isolated.

[0056] In some embodiments, the electromagnetic shielding layer includes a first metal layer 3031, an absorbing layer 3032, and a second metal layer 3033 stacked together. Here, the first metal layer 3031 can be a nickel-copper alloy layer with a thickness greater than or equal to 0.5 mm, the absorbing layer 3032 can be a ferrite absorbing material, and the second metal layer 3033 can be a nickel-copper alloy layer. By providing the above-described electromagnetic shielding layer, noise with a shielding effectiveness greater than or equal to 65 dB can be achieved.

[0057] In some embodiments, such as Figure 3 As shown, the scanning electron microscope also includes:

[0058] The connection terminal 304 includes a first port and a second port. The first port is electrically connected to the output terminal of the amplifier and the noise shielding component, and the second port is electrically connected to the input terminal of the analog-to-digital converter.

[0059] By electrically connecting the first port to the amplifier's output and the noise shielding component, the potential at the amplifier's output can be made the same as the potential of the noise shielding component, thus suppressing spatial radiation coupling.

[0060] Here, the connection end can be a spring-loaded finger contact, which can achieve 360° equipotential connection between the amplifier's output and the noise shielding component.

[0061] In some examples, such as Figure 5 As shown, Figure 5 This is a schematic diagram illustrating the connection of an exemplary amplifier output terminal. The connection cable for the amplifier output terminal can be a coaxial shielded cable, such as... Figure 5 As shown, the coaxial shielded cable may include an inner conductor layer 501 and an outer braided layer 502. The inner conductor layer may be electrically connected to the noise shielding assembly 301 via spring finger contacts 304.

[0062] In some embodiments, such as Figure 3 As shown, the scanning electron microscope also includes:

[0063] An isolation structure 305 is disposed on the side of the electron gun power supply 306 near the analog-to-digital converter. For example... Figure 3 As shown, an isolation structure can be provided on the side of the electron gun power supply 306 near the analog-to-digital converter. The isolation structure can be a metal partition.

[0064] In some examples, the isolation structure described above can be a silver-plated isolation structure with a surface thickness greater than or equal to 5 μm. The isolation structure can be electrically connected to the third reference voltage terminal 30. By setting the isolation structure, the noise of the power supply of the electron gun can be avoided from affecting the charged particle beam signal, thereby improving the quality of the image generated by the charged particle beam signal based on semiconductor reflection.

[0065] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in the details for the sake of brevity.

[0066] The functional blocks shown in the above-described structural diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. Programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried on a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0067] It should also be noted that the exemplary embodiments mentioned in this application describe methods or apparatuses based on a series of steps or devices. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0068] The aspects of this application have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (devices), and computer program products according to embodiments of this application. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that these instructions, executable via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by dedicated hardware performing the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0069] The above description is merely a specific embodiment of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the devices, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A scanning electron microscope device, characterized in that, include: An electron gun, wherein the cavity of the electron gun is electrically connected to a first reference voltage terminal; A detector is disposed inside the cavity of the electron gun and is electrically connected to the first reference voltage terminal; An amplifier, wherein the input terminal of the amplifier is electrically connected to the output terminal of the detector, and the amplifier is electrically connected to the first reference voltage terminal; An analog-to-digital converter (ADC) is provided, wherein the input terminal of the ADC is electrically connected to the output terminal of the amplifier, the first terminal of the ADC's power supply is electrically connected to the ADC, and the second terminal of the ADC's power supply is electrically connected to a second reference voltage terminal.

2. The scanning electron microscope apparatus according to claim 1, characterized in that, The amplifier includes an adder amplifier and multiple differential amplifiers; The plurality of differential amplifiers are connected in parallel between the output of the detector and the input of the adder amplifier; The output terminal of the adder amplifier is electrically connected to the input terminal of the analog-to-digital converter. The first terminal of the power supply of the adder amplifier is electrically connected to the adder amplifier, and the second terminal of the power supply of the adder amplifier is electrically connected to the second reference voltage terminal.

3. The scanning electron microscope apparatus according to claim 2, characterized in that, Also includes: A variable gain amplifier, wherein the input terminal of the variable gain amplifier is electrically connected to the output terminal of the adder amplifier, the output terminal of the variable gain amplifier is electrically connected to the input terminal of the analog-to-digital converter, the first terminal of the power supply of the variable gain amplifier is electrically connected to the analog-to-digital converter, and the second terminal of the power supply of the variable gain amplifier is electrically connected to the second reference voltage terminal.

4. The scanning electron microscope apparatus according to claim 1, characterized in that, Also includes: A first filter, wherein a first end of the first filter is electrically connected to a first end of the power supply of the analog-to-digital converter, and a second end of the first filter is electrically connected to the analog-to-digital converter.

5. The scanning electron microscope apparatus according to claim 1, characterized in that, Also includes: The second filter has a first terminal electrically connected to the first terminal of the power supply of the amplifier, and a second terminal electrically connected to the amplifier.

6. The scanning electron microscope apparatus according to claim 1, characterized in that, Also includes: A noise shielding assembly, wherein the amplifier is disposed inside the noise shielding assembly.

7. The scanning electron microscope apparatus according to claim 6, characterized in that, The noise shielding assembly includes a housing and an electromagnetic shielding layer, wherein the electromagnetic shielding layer is disposed inside the housing; The housing and the electromagnetic shielding layer are electrically connected to the third reference voltage terminal.

8. The scanning electron microscope apparatus according to claim 7, characterized in that, The electromagnetic shielding layer comprises a first metal layer, a wave-absorbing layer, and a second metal layer stacked together.

9. The scanning electron microscope apparatus according to claim 6, characterized in that, Also includes: The connection terminal includes a first port and a second port. The first port is electrically connected to the output terminal of the amplifier and the noise shielding component, and the second port is electrically connected to the input terminal of the analog-to-digital converter.

10. The scanning electron microscope apparatus according to claim 1, characterized in that, Also includes: An isolation structure is provided on the side of the electron gun's power supply near the analog-to-digital converter.

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